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The effect of finger joint hypomobility on precision grip force
Journal of Hand Therapy 26 (2013) 323e329
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Scientific/Clinical Article
The effect of finger joint hypomobility on precision grip force Cesar de Souza Campos Jr. PT a, Marcelo Anderson Bracht PT a, Marcio José dos Santos PhD a, b, * a b
Department of Physical Therapy, Center of Health Sciences and Sport, Santa Catarina State University, Santa Catarina, Brazil Department of Physical Therapy and Rehabilitation Sciences, School of Health Professions, Kansas University Medical Center, Kansas City, KS, USA
a r t i c l e i n f o
a b s t r a c t
Article history: Received 13 November 2012 Received in revised form 14 May 2013 Accepted 19 May 2013 Available online 16 July 2013
Study design: Repeated measures experiment. Introduction: Traumatic injuries and certain other diseases of the hand typically affect mobility of the finger joints. Decreased mobility may alter grip force control while one is grasping and lifting objects. However, the effect of finger joint hypomobility on grip force control has not yet been systematically investigated. Purpose of the study: The aim of this study was to investigate the effects of limited finger joint mobility, without other associated symptoms like pain, or sensory/proprioceptive deficits, on precision grip force control. Methods: Fifteen healthy subjects performed a pinching and lifting task of an object equipped with a force sensor and an accelerometer, via opposition of the thumb and index finger, in the following experimental conditions: unrestricted finger joint movement (UJM), restricted finger flexion (RFF), restricted finger extension (RFE), mock restricted flexion (MRF), mock restricted extension (MRE). The following pinch force variables were measured and analyzed: grip force at lift off, grip force peak, load force peak, latency, and static force. Results: A significant increase in latency (F ¼ 4.41, p < 0.01) was noted during RFE relative to UJM and MRF conditions. There were no statistically-significant differences between the conditions among the other variables of precision grip force control. Conclusions: Limited joint mobility of the thumb and index finger may cause temporal changes in precision grip force control, which can lead to reduced manual dexterity. Restoring range of motion might be an important priority to improve thumb-index pinch force control during manipulative tasks. Published by Elsevier Inc. on behalf of Hanley & Belfus, an imprint of Elsevier Inc.
Keywords: Restriction Limited motion Prehension Latency Lifting
Introduction To successfully manipulate objects during daily manual activities, humans must have accurate control of their grip force.1 This control consists of applying adequate force to neither deform the object in hand nor allow it to slip from the grasping fingers. The strength of this force is determined by the object’s characteristics, such as its weight, shape, and weight distribution, as well as the friction coefficient that exists between the object’s contact surface and the person’s fingertips.2e4 Furthermore, precise control during object manipulation requires accurate coordination between the grip force and the object’s load force (tangential force) which, in turn, depends upon the mass and acceleration of the object.5e7 Therefore, grip and load forces are coupled in terms of time and * Corresponding author. Mail Stop 2002, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA. Tel.: þ1 913 588 4343; fax: þ1 913 588 84568. E-mail addresses: [email protected], [email protected] (M.J. dos Santos).
magnitude and during dynamic manual tasks, and are usually generated in a predictable way (feed-forward) and adjusted via feedback as the object is lifted. It is known that grip force control is impaired in older adults and in individuals with neurological disease. For example, increased grip force during object manipulation has been described in patients with Parkinson’s disease,8 multiple scleroses,9 cerebral stroke,10,11 chronic somatosensory deafferentation,12 and carpal tunnel syndrome.13 On the other hand, increased grip force when handling objects also has been reported in patients without apparent neurological disease, such as those with neck and upper limb pain14,15 and hand osteoarthritis.16 For the latter, since such individuals have no decreased sensitivity in the fingertips, it has been suggested that the change in grip force control might be due either to joint pain, decreased proprioception, or limitations in finger joint mobility, all common symptoms in these patients. The joint hypomobility/stiffness of the fingers that is commonly observed in patients with traumatic hand injury or orthopedic or rheumatic diseases may cause a mechanical disadvantage while
0894-1130/$ e see front matter Published by Elsevier Inc. on behalf of Hanley & Belfus, an imprint of Elsevier Inc. http://dx.doi.org/10.1016/j.jht.2013.05.007
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someone is grasping or handling objects. This, in turn, prevents patients with limited joint mobility of the hand or fingers, or both, from performing manipulative tasks with the same dexterity as non-disabled individuals. In fact, recent studies have demonstrated, in patients with hand osteoarthritis, that certain parameters of grip force control e like grip force at the moment of object lift-off and lift latency (the duration of time between the instant of grip force application and the time of object lift-off from the contact surface) e are correlated with results of the Moberg Pickup Test17; the latter evaluates precision grip and functional performance of the hand.18 It is not well understood, however, whether these changes in grip force control are caused by limited finger joint mobility itself or by pain. Therefore, the aim of this study was to investigate whether decreased mobility of finger joints, without other associated factors like pain, decreased sensation, and diminished proprioception, affects precision grip force control. To accomplish this, fifteen healthy subjects performed the task of lifting an object equipped with a force sensor and an accelerometer, both with and without different forms of thumb and index finger joint restriction. Based upon the studies mentioned above, our hypothesis was that thumb-index pinch force control would be affected by restricted joint mobility. We felt that the results of this study might help to guide and support future research and interventions in the field of hand rehabilitation. Methods Subjects Fifteen participants (7 males and 8 females; age range: 19e26 years old) were recruited for this study. This sample size was chosen by performing a power analysis based upon previouslyrecorded data and published research17: only 8 subjects were needed to detect statistically-significant differences between the conditions in the precision grip force control variables (see below) with 80% power and 95% confidence. The exclusion criteria were: 1) any upper limb fracture within the last six months; 2) restricted range of motion of the hand or finger joints; 3) loss or decreased sensitivity of the fingertips; 4) neurological disease; 5) neck and/or upper extremity pain; or 6) any other involvement of the upper extremity that could prevent execution of the tasks. Inclusion criteria were: 1) good health; and 2) willingness to participate in the research. All participants were informed about the study objectives and procedures and signed a consent form approved by the local ethics committee (protocol 206/2011). Instrumentation For the experiments, a cylindrical, plastic object (6 cm in diameter, 16 cm in height, and 325 g in weight) was used to evaluate precision grip force control (Fig. 1). The object, designed in the shape of a cup, was equipped with a piezoelectric force sensor
(model 208CO3, PCB Piezotronics Inc.; Depew, New York, USA) installed at its center. Two aluminum pads (2.5 cm wide and 9 cm long) connected to the force sensor with two metallic projections were used as grasping surfaces. A triaxial piezoelectric accelerometer (model 333B32, PCB Piezotronics Inc.; Depew, NY, USA) was affixed to the cup to register acceleration in the x-, y-, and z-planes. Accelerometer and force sensor data were powered with two signal conditioners (ICP R Sensor Signal Conditioner, model Y482A22, and Line-Powered ICP R Signal Conditioner, model 484B06, respectively, PCB Piezotronics Inc.; Depew, NY, USA). The force and accelerometer signals were sampled at 100 Hz with a 16-bit analogdigital converter (National Instruments; Austin, TX, USA) and stored for further analysis. Data collection was performed using the LabView Signal Express software program (version 2.5.1 for Windows, National Instruments; Austin, TX, USA). Clinical examination Using a finger goniometer (Baseline stainless, North Coast Medical Inc.; Gilroy, CA, USA), range of motion was measured for the following joints: 1) thumb (first finger): trapeziometacarpal (TMC) and interphalangeal (IPT); 2) index finger (second finger): proximal interphalangeal (PIP) and distal interphalangeal (DIP). These measurements were taken with and without finger joints restricted. Fingers sensitivity was evaluated using Semmes-Weinstein nylon monofilaments (Touch-TestÔ 5 Piece Hand Kit Sensory Evaluators, North Coast Medical Inc.; Gilroy, CA, USA). The monofilaments were applied three times at each of the following sites: to the skin of the DIP and PIP joint regions, to the pulp of all fingers, and to the metacarpophalangeal joint of the thumb. Accurate detection of touch with a given filament in two out of three trials was considered to be a given tested area’s sensory threshold. The average scores of all sites were used for analysis.16 Experimental procedure Subjects were asked to sit in an adjustable chair with their feet on the floor, their trunk in a vertical position with their xiphoid process about 30 cm from a table where the test object was positioned. Prior to performing the lifting tasks, the subject’s fingertips and the object’s grasping surfaces were cleaned with alcohol swabs to remove any grease or fat. Subjects were required to handle the test object by opposing their thumb and index finger while placed centrally on the grasping surfaces, which had been marked previously. The subject’s initial position was with their shoulder in a neutral position, elbow flexed to approximately 90 , forearm pronated, and wrist in a neutral position while resting on the table. During the lifting tasks, individuals were asked to keep the other three fingers of the same hand in neutral position and not touching the grasping surfaces. The task consisted of lifting the test object vertically from the table; holding it at a point 10 cm above the table; and then, after 5 s,
Fig. 1. (A) Unrestricted finger joint movement (UJM); goniometric evaluation of the index finger with (B) restricted finger flexion (RFF); (C) restricted finger extension (RFE); (D) hand position relative to the test object.
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After creating the restricted joint conditions, which simulated “tissue stretch” end feel, joint angles were measured to quantify the degree of restriction in the assessed joints. Before starting data collection and orthotic placement, each subject performed 10 trials (without joint restriction) to become familiar with the test object and procedure. Data processing
Fig. 2. Grip and load force curves and grip force control variables.
returning the object to its initial position. Subjects were instructed to perform the lifting tasks as naturally as possible, starting with the experimenter’s verbal command “go” and returning the object to its starting position with the command “return.” A series of eight trials of this procedure was performed in five different conditions, which were assigned in a random order. These five conditions were: 1) unrestricted finger joint movement (UJM); 2) restricted finger flexion (RFF); for this, subjects were asked to fully extent their thumb and index fingers (TMC, IPT, PIP, and DIP joints) while an orthotic device (2 pieces of elastic tape 1 cm wide one fingerlength long) (Kinesio Tex Gold, Kinesio Holding Corp.; Albuquerque, NM, USA) was placed with maximum tension, fixed to the dorsal aspect of each finger joint; 3) mock restricted flexion (MRF); subjects were instructed to fully extend their thumb and index fingers (TMC, IPT, PIP, and DIP joints) while the same orthosis was applied to the same location as in the RFF condition, but without tension; 4) restricted finger extension (RFE): this condition involved maximal flexion of the thumb and index fingers (TMC, IPT, PIP, and DIP joints), with the same orthosis (4 pieces) positioned with maximum tension, fixed to the lateral aspects of these finger joints on both the medial and lateral side; 5) mock restricted extension (MRE); for this, subjects were asked to maximally flex their thumb and index fingers (TMC, IPT, PIP, and DIP joints) while the orthosis (4 strips) was applied to the same locations as for the RFE condition, but without tension (Fig. 1). The mock restriction conditions were used to discard potential effects of the orthotic intervention on fingers sensitivity, which might influence thumbindex pinch force control. These joints were selected based on the finger joint restrictions observed in patients with osteoarthritis of the hand, according to criteria established by the American College of Rheumatology.19 To avoid any loss or decrease in tactile sensitivity, which might influence grip force control,20,21 the orthosis was never affixed to the ventral aspect of the fingertips.
The collected force sensor and accelerometer signals were visualized and inspected on a computer screen using the software program Matlab (version 7.12, The MathWorks Inc.; Natick, MA, USA). This program identified and measured the following variables: 1) Grip Force at the Moment of Lift-off (GFLO), which is the thumb-index pinch force applied at the instant the object leaves the surface of the table and represents anticipatory grip force control (planned forces)22; the moment of object lift-off was indicated by the acceleration signal; 2) Load Force Peak (LFP), defined as the maximum Load Force achieved during object lifting, calculated as LF¼m*(AccZ þ g)23,24 where Load Force Peak (LF) in Newtons (N) was calculated by multiplication of the object’s mass (m), in kilograms, by the addition of the recorded vertical acceleration (AccZ) and gravity (g).12 Because the tasks consisted of vertical lifting trials without object tilting, loading components acting in the direction of the applied grip forces (x-axis) and sagittal (y-axis) to it were not included in the calculation; 3) Grip Force Peak (GFP), defined as the maximum thumb-index pinch force achieved during object lifting, indicating somatosensory feedback-based grip force control during the dynamic phase (lifting)11; 4) Latency, calculated as the duration of time between the onset of thumb-index pinch force application and the moment of object lift-off from the table, which indicates the coordination of grip and load forces25; and 5) Static Force (SF), defined as the mean thumb-index pinch force from the point where movement velocity becomes approximately zero after the object’s vertical lifting to 4 s, when individuals were asked to hold it statically; this variable represents somatosensory feedback-based grip force control during the static phase (post lifting)11; the last second of the task was removed from analysis to ensure that all individuals were still in a static phase (Fig. 2). Statistical analysis Repeated measures analysis of variance (ANOVA) with a General Linear Model option (polynomial) was performed to compare the precision grip force control variables (GFLO, GFP, LFP, latency, and SF) across the five test conditions (UJM, RFF, MRF, RFE, MRE). Within subject correlation structure was taken to be compound symmetry, a standard choice. Post hoc analysis was performed to determine which pair or pairs of conditions were statistically different. The Bonferroni correction was used to adjust for multiple
Table 1 Normal range of motion and amount of applied restriction (means and standard deviations) Joint
Range of motion (degree)
PIP
Extensioneflexion 0e102
DIP
0e87.7
Percentage of restriction (%) SD
Flexion 45.78
SD 17.69
Extension 58.14
SD 16.24
29.65
15.38
51.54
14.56
34.39
20.61
44.31
18.11
Opponency 45.73
SD 5.9
Abduction 31.61
SD 4.21
4.14 7.99 IPT TMC
0e88.7 Opponency 0e36.6
SD 3.13
2.97 Abduction 0e44.6
SD 4.77
Proximal interphalangeal joint (PIP), distal interphalangeal joint (DIP), interphalangeal joint of thumb (IPT), and trapeziometacarpal joint (TMC).
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Force Peak (F ¼ 1.04, p ¼ 0.39) or Static Force (F ¼ 1.6, p ¼ 0.18) (Fig. 4). Discussion
Fig. 3. Means and standard errors for latency recorded under the following conditions: unrestricted joint movement (UJM); mock restricted flexion (MRF); mock restricted extension (MRE); restricted finger flexion (RFF); restricted finger extension (RFE). * represents a statistically-significant difference between RFE and UJM (p < 0.05). ** represents a statistically-significant difference between the RFE and MRF (p 0.05).
comparisons. SPSS software (Statistical Package for the Social Sciences, version 13.0) was used for all statistical analysis. The adopted significance level was p < 0.05 and all tests were twotailed.
Results The orthotic intervention we used to restrict the range of motion of finger joints was effective. The orthosis applied to the index and thumb finger joints caused clinically relevant limitations in all target joints (PIP, DIP, IPT, TMC) (Table 1). Repeated measures ANOVA identified latency as significantly different (F ¼ 4.41, p < 0.01) between the five conditions, with post hoc analysis detecting a significant increase in latency during RFE relative to two control conditions. In particular, Latency during RFE was significantly longer than with UJM (p < 0.01) and MRF (p ¼ 0.02) (Fig. 3). No statistically-significant differences between the conditions were noted for the other variables of precision grip force control: GFLO (F ¼ 2.03, p ¼ 0.1); Grip Force Peak (F ¼ 2.97, p ¼ 0.90); Load
In a recent study, patients with osteoarthritis of the hand were discovered to apply greater grip forces and exhibit increased latency while grasping and lifting a test object.16 Since these subjects had no deficits of tactile sensitivity in their fingertips, it was suggested that changes in their grip force control were caused by limited joint mobility of the fingers, due to erosion and edema, which is common in patients with hand osteoarthritis. However, in addition to important finger joint restrictions, these patients may experience other symptoms like pain, lost sensation, proprioceptive deficits, and muscular weakness, which also can affect grip force control.15 Consequently, the aim of the current study was to investigate the effects of isolated finger joint hypomobility on precision grip force control. To our knowledge, this is the first reported study to demonstrate that limited range of motion of the finger joints, in itself, can adversely affect thumb-index pinch force control. Our most striking result was that limited extension of the thumb and index fingers significantly increased latency while pinching and lifting the test object. Given that our study subjects were healthy and tested normal for sensitivity, this change in latency might be attributed to the restrictions in finger joint movement. Latency is considered a measure of coordination between the muscles of the hand used to grab an object, and the proximal muscles of the arm, which are used to lift and hold it without support.26,27 Others have investigated this variable, dividing latency into two phases, preload and load, which represent the time taken for grasp stabilization and the time needed to develop appropriate lifting forces, respectively. These two phases together (as latency) represent the temporal coordination of grip and load forces25 and are usually disrupted in neurologically-impaired patients; for example, those with hemiparesis,25,26 cerebellar dysfunction27,28 or Parkinson’s disease.8,29 Various factors might explain why changes in latency also have been observed in patients without neurological problems16 or in healthy individuals with isolated limited finger joint mobility. Decreased range of motion of the finger joints may cause
Fig. 4. Means and standard errors for load force peak, grip force at lift-off (GFLO), grip force peak and static force recorded under the following conditions: unrestricted joint movement (UJM), mock restricted flexion (MRF), mock restricted extension (MRE), restricted finger flexion (RFF), restricted finger extension (RFE).
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a biomechanical disadvantage grasping objects, which inherently makes tasks like holding and lifting them difficult. For instance, it is possible that joint restriction, especially of finger extension, makes individuals alter the placement of their fingers on the object, and adjusting their finger position could delay the lift. In fact, studies involving kinematic analysis of the finger joints have demonstrated that healthy individuals change their digit placement on objects to compensate for asymmetrical tangential forces while lifting an object with its center of mass deviated from the center.30,31 In one study by Fu et al, subjects learned to minimize the variability in compensatory torque by modulating digit force as a function of digit position. Therefore, in all likelihood, digit placement on objects contributes to better distribution of digit force in the case of asymmetric digit load forces30 or when ‘correct/usual’ placement is no longer available, as in the present study. Despite proper modulations in grip force, the time required to accomplish the grasping and lifting tasks was adversely affected, which could influence one’s functional capacity to grasp and lift objects. For example, a strong positive correlation between the Moberg Peak-Up Test (MPUT), a test used to evaluate manual dexterity, and latency has been identified in patients with osteoarthritis; i.e., the higher the latency, the more time individuals took to complete the MPUT.17 This suggests that limitations in finger range of motion increase latency that, in turn, leads to a decline in manual dexterity. Conversely, the finger movement restrictions imposed in this study did not affect any of the force control variables. For instance, the grip force at the moment of lift-off (GFLO), grip force peak (GFP), and static force (SF) were no different in any of the experimental conditions. This suggests that the central nervous system compensates for decreased movement of finger joints to adjust precision grip force adequately, both before (GFLO) and during the lift as feedback on weight and other forces are received (GFP and SF). In addition, the finger joint restrictions imposed in this study did not cause the subjects to significantly change their precision grip strategy (pinch type), which could generate changes in the variables of grip force control.32 Furthermore, it seems that the small changes induced by lengthening the muscles involved in our experimental task, in certain conditions, did not affect precision grip force control. It is known that changes in a muscle’s length influences the magnitude of tension that muscle generates.33 For example, Werremeyer and Cole34 demonstrated that different positions of the wrist that considerably alter the length of the extrinsic flexor and extensor muscles of the fingers, both in flexion and extension, lead to changes in precision grip force control in healthy subjects. Therefore, the differences in muscular length due to our orthotic intervention seem to be not substantial enough to induce changes in the force control variables. Limitations of this study and recommendations for future research Admittedly, our study has certain limitations that are important to mention. First, while the outcomes of this study provide important information on the effects of hypomobility on control of precision grip force, it might not be generalizable to clinic populations, given that this study was conducted only on healthy individuals. It is known, however, that patients suffering from musculoskeletal diseases, in addition to having joint hypomobility, often experience other associated symptoms like pain, swelling, proprioceptive deficits and muscular weakness. Including them in this study would have conflicted with our purpose of isolating joint hypomobility to determine its unique role in lost hand function. Clearly, further research to determine the relative importance of these diverse factors in precision grip force control is warranted. Second, our experimental task involved the precision grip force
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applied by the thumb and index finger. While this approach has been used in a number of studies involving healthy individuals and clinical populations,3,11,25,35 investigating the effect of hypomobility in all fingers of the hand using a device with five individual sensors might better demonstrate the effects of hand hypomobility on grip force control. Further studies are needed to address this issue. Conclusions To our knowledge, this is the first report demonstrating how limited range of motion of the finger joints adversely affects precision grip force control. More specifically, such limitations appear to mostly prolong the time between the beginning of applied thumb-index pinch force on an object and its lift-off. This, in essence, represents increased difficulty pinching and lifting objects promptly, which can adversely affect manual dexterity and cause limitations in any activities of daily living that involve object manipulation. Thus, treatment strategies that aim to restore range of motion in finger joints might improve the temporal aspects of precision grip force control and, consequently, manual dexterity. References 1. Johansson RS, Westling G. Coordinated isometric muscle commands adequately and erroneously programmed for the weight during lifting task with precision grip. Exp Brain Res. 1988;71(1):59e71. 2. Bensmail D, Sarfeld AS, Fink GR, Nowak DA. Intermanual transfer of sensorimotor memory for grip force when lifting objects: the role of wrist angulation. Clin Neurophysiol. 2010;121(3):402e407. 3. Johansson RS. Dynamic use of tactile afferent signals in control of dexterous manipulation. Adv Exp Med Biol. 2002;508:397e410. 4. Cole KJ, Abbs JH. Grip force adjustments evoked by load force perturbations of a grasped object. J Neurophysiol. 1988;60(4):1513e1522. 5. Johansson RS, Westling G. Roles of glabrous skin receptors and sensorimotor memory in automatic control of precision grip when lifting rougher or more slippery objects. Exp Brain Res. 1984;56(3):550e564. 6. Johansson RS, Westling G. Significance of cutaneous input for precise hand movements. Electroencephalogr Clin Neurophysiol Suppl. 1987;39:53e57. 7. de Gruijl JR, van der Smagt P, De Zeeuw CI. Anticipatory grip force control using a cerebellar model. Neuroscience. 2009;162(3):777e786. 8. Fellows SJ, Noth J, Schwarz M. Precision grip and Parkinson’s disease. Brain. 1998;121(Pt 9):1771e1784. 9. Iyengar V, Santos MJ, Ko M, Aruin AS. Grip force control in individuals with multiple sclerosis. Neurorehabil Neural Repair. 2009;23(8):855e861. 10. Hermsdörfer J, Hagl E, Nowak DA, Marquardt C. Grip force control during object manipulation in cerebral stroke. Clin Neurophysiol. 2003;114(5): 915e929. 11. Quaney BM, Perera S, Maletsky R, Luchies CW, Nudo RJ. Impaired grip force modulation in the ipsilesional hand after unilateral middle cerebral artery stroke. Neurorehabil Neural Repair. 2005;19(4):338e349. 12. Hermsdörfer J, Elias Z, Cole JD, Quaney BM, Nowak DA. Preserved and impaired aspects of feed-forward grip force control after chronic somatosensory deafferentation. Neurorehabil Neural Repair. 2008;22(4):374e384. 13. Lowe BD, Freivalds A. Effect of carpal tunnel syndrome on grip force coordination on hand tools. Ergonomics. 1999;42(4):550e564. 14. Seo NJ, Sindhu BS, Shechtman O. Influence of pain associated with musculoskeletal disorders on grip force timing. J Hand Ther. 2011;24(4):335e343. quiz 344. 15. Huysmans MA, Hoozemans MJ, Visser B, van Dieën JH. Grip force control in patients with neck and upper extremity pain and healthy controls. Clin Neurophysiol. 2008;119(8):1840e1848. 16. de Oliveira DG, Nunes PM, Aruin AS, Dos Santos MJ. Grip force control in individuals with hand osteoarthritis. J Hand Ther. 2011;24(4):345e354. quiz 355. 17. Nunes PM, Oliveira DG, Aruin AS, dos Santos MJ. Relationship between hand function and grip force control in women with hand osteoarthritis. J Rehabil Res Dev. 2012;49:12. 18. Moberg E. Objective methods for determining the functional value of sensibility in the hand. J Bone Jt Surg Br. 1958;40-B(3):454e476. 19. Altman R, Alarcón G, Appelrouth D, et al. The American college of rheumatology criteria for the classification and reporting of osteoarthritis of the hand. Arthritis Rheum. 1990;33(11):1601e1610. 20. Nowak DA, Hermsdörfer J. Selective deficits of grip force control during object manipulation in patients with reduced sensibility of the grasping digits. Neurosci Res. 2003;47(1):65e72. 21. Nowak DA, Hermsdörfer J, Glasauer S, Philipp J, Meyer L, Mai N. The effects of digital anaesthesia on predictive grip force adjustments during vertical movements of a grasped object. Eur J Neurosci. 2001;14(4):756e762.
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22. Gordon AM, Westling G, Cole KJ, Johansson RS. Memory representations underlying motor commands used during manipulation of common and novel objects. J Neurophysiol. 1993;69(6):1789e1796. 23. Hermsdörfer J, Hagl E, Nowak DA. Deficits of anticipatory grip force control after damage to peripheral and central sensorimotor systems. Hum Mov Sci. 2004;23(5):643e662. 24. Nowak DA, Glasauer S, Meyer L, Mait N, Hermsdörfer J. The role of cutaneous feedback for anticipatory grip force adjustments during object movements and externally imposed variation of the direction of gravity. Somatosens Mot Res. 2002;19(1):49e60. 25. Raghavan P, Krakauer JW, Gordon AM. Impaired anticipatory control of fingertip forces in patients with a pure motor or sensorimotor lacunar syndrome. Brain. 2006;129(Pt 6):1415e1425. 26. Aruin AS. Support-specific modulation of grip force in individuals with hemiparesis. Arch Phys Med Rehabil. 2005;86(4):768e775. 27. Fellows SJ, Ernst J, Schwarz M, Töpper R, Noth J. Precision grip deficits in cerebellar disorders in man. Clin Neurophysiol. 2001;112(10):1793e 1802.
28. Brandauer B, Timmann D, Häusler A, Hermsdörfer J. Influences of load characteristics on impaired control of grip forces in patients with cerebellar damage. J Neurophysiol. 2010;103(2):698e708. 29. Fellows SJ, Noth J. Grip force abnormalities in de novo Parkinson’s disease. Mov Disord. 2004;19(5):560e565. 30. Fu Q, Zhang W, Santello M. Anticipatory planning and control of grasp positions and forces for dexterous two-digit manipulation. J Neurosci. 2010;30(27): 9117e9126. 31. Salimi I, Hollender I, Frazier W, Gordon AM. Specificity of internal representations underlying grasping. J Neurophysiol. 2000;84(5):2390e2397. 32. McDonnell MN, Ridding MC, Flavel SC, Miles TS. Effect of human grip strategy on force control in precision tasks. Exp Brain Res. 2005;161(3):368e373. 33. Gordon AM, Huxley AF, Julian FJ. The variation in isometric tension with sarcomere length in vertebrate muscle fibres. J Physiol. 1966;184(1):170e192. 34. Werremeyer MM, Cole KJ. Wrist action affects precision grip force. J Neurophysiol. 1997;78(1):271e280. 35. Westling G, Johansson RS. Factors influencing the force control during precision grip. Exp Brain Res. 1984;53(2):277e284.
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JHT Read for Credit Quiz: #284
Record your answers on the Return Answer Form found on the tear-out coupon at the back of this issue or to complete online and use a credit card, go to JHTReadforCredit.com. There is only one best answer for each question. #1. The strength of grip force used to manipulate objects is mostly determined by a. force at the moment of lift off b. movement velocity and direction c. object’s characteristics and friction coefficient d. object’s velocity and t rajectory #2. Which of the grip force control variables below have been shown by previous studies to be adversely affected due to decreased mobility of the fingers joints a. latency b. grip force peak c. time lag d. time to grip force peak #3. Individuals with finger joint restriction, especially finger extension, showed prolonged latency during pinching and
lifting the instrumented object used in this study. The authors suggested this alteration can be attributed respectively to a. decreased sensitivity of the fingers tip and decreased proprioception b. proprioceptive deficits and increased pain c. asymmetrical tangential forces and increased rotator toques d. biomechanical disadvantage and unusual finger placement #4. The grip force control variable denominated latency represents a. somatosensory feedback-based grip force control b. anticipatory grip force control c. coordination between grip and load force d. compensatory grip force control #5. Limited ROM was found to not affect pinch control a. true b. false When submitting to the HTCC for re-certification, please batch your JHT RFC certificates in groups of 3 or more to get full credit.
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JHT READ
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CREDIT ARTICLE #284.
Scientific/Clinical Article
The effect of finger joint hypomobility on precision grip force Cesar de Souza Campos Jr. PT a, Marcelo Anderson Bracht PT a, Marcio José dos Santos PhD a, b, * a b
Department of Physical Therapy, Center of Health Sciences and Sport, Santa Catarina State University, Santa Catarina, Brazil Department of Physical Therapy and Rehabilitation Sciences, School of Health Professions, Kansas University Medical Center, Kansas City, KS, USA
a r t i c l e i n f o
a b s t r a c t
Article history: Received 13 November 2012 Received in revised form 14 May 2013 Accepted 19 May 2013 Available online 16 July 2013
Study design: Repeated measures experiment. Introduction: Traumatic injuries and certain other diseases of the hand typically affect mobility of the finger joints. Decreased mobility may alter grip force control while one is grasping and lifting objects. However, the effect of finger joint hypomobility on grip force control has not yet been systematically investigated. Purpose of the study: The aim of this study was to investigate the effects of limited finger joint mobility, without other associated symptoms like pain, or sensory/proprioceptive deficits, on precision grip force control. Methods: Fifteen healthy subjects performed a pinching and lifting task of an object equipped with a force sensor and an accelerometer, via opposition of the thumb and index finger, in the following experimental conditions: unrestricted finger joint movement (UJM), restricted finger flexion (RFF), restricted finger extension (RFE), mock restricted flexion (MRF), mock restricted extension (MRE). The following pinch force variables were measured and analyzed: grip force at lift off, grip force peak, load force peak, latency, and static force. Results: A significant increase in latency (F ¼ 4.41, p < 0.01) was noted during RFE relative to UJM and MRF conditions. There were no statistically-significant differences between the conditions among the other variables of precision grip force control. Conclusions: Limited joint mobility of the thumb and index finger may cause temporal changes in precision grip force control, which can lead to reduced manual dexterity. Restoring range of motion might be an important priority to improve thumb-index pinch force control during manipulative tasks. Published by Elsevier Inc. on behalf of Hanley & Belfus, an imprint of Elsevier Inc.
Keywords: Restriction Limited motion Prehension Latency Lifting
Introduction To successfully manipulate objects during daily manual activities, humans must have accurate control of their grip force.1 This control consists of applying adequate force to neither deform the object in hand nor allow it to slip from the grasping fingers. The strength of this force is determined by the object’s characteristics, such as its weight, shape, and weight distribution, as well as the friction coefficient that exists between the object’s contact surface and the person’s fingertips.2e4 Furthermore, precise control during object manipulation requires accurate coordination between the grip force and the object’s load force (tangential force) which, in turn, depends upon the mass and acceleration of the object.5e7 Therefore, grip and load forces are coupled in terms of time and * Corresponding author. Mail Stop 2002, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA. Tel.: þ1 913 588 4343; fax: þ1 913 588 84568. E-mail addresses: [email protected], [email protected] (M.J. dos Santos).
magnitude and during dynamic manual tasks, and are usually generated in a predictable way (feed-forward) and adjusted via feedback as the object is lifted. It is known that grip force control is impaired in older adults and in individuals with neurological disease. For example, increased grip force during object manipulation has been described in patients with Parkinson’s disease,8 multiple scleroses,9 cerebral stroke,10,11 chronic somatosensory deafferentation,12 and carpal tunnel syndrome.13 On the other hand, increased grip force when handling objects also has been reported in patients without apparent neurological disease, such as those with neck and upper limb pain14,15 and hand osteoarthritis.16 For the latter, since such individuals have no decreased sensitivity in the fingertips, it has been suggested that the change in grip force control might be due either to joint pain, decreased proprioception, or limitations in finger joint mobility, all common symptoms in these patients. The joint hypomobility/stiffness of the fingers that is commonly observed in patients with traumatic hand injury or orthopedic or rheumatic diseases may cause a mechanical disadvantage while
0894-1130/$ e see front matter Published by Elsevier Inc. on behalf of Hanley & Belfus, an imprint of Elsevier Inc. http://dx.doi.org/10.1016/j.jht.2013.05.007
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someone is grasping or handling objects. This, in turn, prevents patients with limited joint mobility of the hand or fingers, or both, from performing manipulative tasks with the same dexterity as non-disabled individuals. In fact, recent studies have demonstrated, in patients with hand osteoarthritis, that certain parameters of grip force control e like grip force at the moment of object lift-off and lift latency (the duration of time between the instant of grip force application and the time of object lift-off from the contact surface) e are correlated with results of the Moberg Pickup Test17; the latter evaluates precision grip and functional performance of the hand.18 It is not well understood, however, whether these changes in grip force control are caused by limited finger joint mobility itself or by pain. Therefore, the aim of this study was to investigate whether decreased mobility of finger joints, without other associated factors like pain, decreased sensation, and diminished proprioception, affects precision grip force control. To accomplish this, fifteen healthy subjects performed the task of lifting an object equipped with a force sensor and an accelerometer, both with and without different forms of thumb and index finger joint restriction. Based upon the studies mentioned above, our hypothesis was that thumb-index pinch force control would be affected by restricted joint mobility. We felt that the results of this study might help to guide and support future research and interventions in the field of hand rehabilitation. Methods Subjects Fifteen participants (7 males and 8 females; age range: 19e26 years old) were recruited for this study. This sample size was chosen by performing a power analysis based upon previouslyrecorded data and published research17: only 8 subjects were needed to detect statistically-significant differences between the conditions in the precision grip force control variables (see below) with 80% power and 95% confidence. The exclusion criteria were: 1) any upper limb fracture within the last six months; 2) restricted range of motion of the hand or finger joints; 3) loss or decreased sensitivity of the fingertips; 4) neurological disease; 5) neck and/or upper extremity pain; or 6) any other involvement of the upper extremity that could prevent execution of the tasks. Inclusion criteria were: 1) good health; and 2) willingness to participate in the research. All participants were informed about the study objectives and procedures and signed a consent form approved by the local ethics committee (protocol 206/2011). Instrumentation For the experiments, a cylindrical, plastic object (6 cm in diameter, 16 cm in height, and 325 g in weight) was used to evaluate precision grip force control (Fig. 1). The object, designed in the shape of a cup, was equipped with a piezoelectric force sensor
(model 208CO3, PCB Piezotronics Inc.; Depew, New York, USA) installed at its center. Two aluminum pads (2.5 cm wide and 9 cm long) connected to the force sensor with two metallic projections were used as grasping surfaces. A triaxial piezoelectric accelerometer (model 333B32, PCB Piezotronics Inc.; Depew, NY, USA) was affixed to the cup to register acceleration in the x-, y-, and z-planes. Accelerometer and force sensor data were powered with two signal conditioners (ICP R Sensor Signal Conditioner, model Y482A22, and Line-Powered ICP R Signal Conditioner, model 484B06, respectively, PCB Piezotronics Inc.; Depew, NY, USA). The force and accelerometer signals were sampled at 100 Hz with a 16-bit analogdigital converter (National Instruments; Austin, TX, USA) and stored for further analysis. Data collection was performed using the LabView Signal Express software program (version 2.5.1 for Windows, National Instruments; Austin, TX, USA). Clinical examination Using a finger goniometer (Baseline stainless, North Coast Medical Inc.; Gilroy, CA, USA), range of motion was measured for the following joints: 1) thumb (first finger): trapeziometacarpal (TMC) and interphalangeal (IPT); 2) index finger (second finger): proximal interphalangeal (PIP) and distal interphalangeal (DIP). These measurements were taken with and without finger joints restricted. Fingers sensitivity was evaluated using Semmes-Weinstein nylon monofilaments (Touch-TestÔ 5 Piece Hand Kit Sensory Evaluators, North Coast Medical Inc.; Gilroy, CA, USA). The monofilaments were applied three times at each of the following sites: to the skin of the DIP and PIP joint regions, to the pulp of all fingers, and to the metacarpophalangeal joint of the thumb. Accurate detection of touch with a given filament in two out of three trials was considered to be a given tested area’s sensory threshold. The average scores of all sites were used for analysis.16 Experimental procedure Subjects were asked to sit in an adjustable chair with their feet on the floor, their trunk in a vertical position with their xiphoid process about 30 cm from a table where the test object was positioned. Prior to performing the lifting tasks, the subject’s fingertips and the object’s grasping surfaces were cleaned with alcohol swabs to remove any grease or fat. Subjects were required to handle the test object by opposing their thumb and index finger while placed centrally on the grasping surfaces, which had been marked previously. The subject’s initial position was with their shoulder in a neutral position, elbow flexed to approximately 90 , forearm pronated, and wrist in a neutral position while resting on the table. During the lifting tasks, individuals were asked to keep the other three fingers of the same hand in neutral position and not touching the grasping surfaces. The task consisted of lifting the test object vertically from the table; holding it at a point 10 cm above the table; and then, after 5 s,
Fig. 1. (A) Unrestricted finger joint movement (UJM); goniometric evaluation of the index finger with (B) restricted finger flexion (RFF); (C) restricted finger extension (RFE); (D) hand position relative to the test object.
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After creating the restricted joint conditions, which simulated “tissue stretch” end feel, joint angles were measured to quantify the degree of restriction in the assessed joints. Before starting data collection and orthotic placement, each subject performed 10 trials (without joint restriction) to become familiar with the test object and procedure. Data processing
Fig. 2. Grip and load force curves and grip force control variables.
returning the object to its initial position. Subjects were instructed to perform the lifting tasks as naturally as possible, starting with the experimenter’s verbal command “go” and returning the object to its starting position with the command “return.” A series of eight trials of this procedure was performed in five different conditions, which were assigned in a random order. These five conditions were: 1) unrestricted finger joint movement (UJM); 2) restricted finger flexion (RFF); for this, subjects were asked to fully extent their thumb and index fingers (TMC, IPT, PIP, and DIP joints) while an orthotic device (2 pieces of elastic tape 1 cm wide one fingerlength long) (Kinesio Tex Gold, Kinesio Holding Corp.; Albuquerque, NM, USA) was placed with maximum tension, fixed to the dorsal aspect of each finger joint; 3) mock restricted flexion (MRF); subjects were instructed to fully extend their thumb and index fingers (TMC, IPT, PIP, and DIP joints) while the same orthosis was applied to the same location as in the RFF condition, but without tension; 4) restricted finger extension (RFE): this condition involved maximal flexion of the thumb and index fingers (TMC, IPT, PIP, and DIP joints), with the same orthosis (4 pieces) positioned with maximum tension, fixed to the lateral aspects of these finger joints on both the medial and lateral side; 5) mock restricted extension (MRE); for this, subjects were asked to maximally flex their thumb and index fingers (TMC, IPT, PIP, and DIP joints) while the orthosis (4 strips) was applied to the same locations as for the RFE condition, but without tension (Fig. 1). The mock restriction conditions were used to discard potential effects of the orthotic intervention on fingers sensitivity, which might influence thumbindex pinch force control. These joints were selected based on the finger joint restrictions observed in patients with osteoarthritis of the hand, according to criteria established by the American College of Rheumatology.19 To avoid any loss or decrease in tactile sensitivity, which might influence grip force control,20,21 the orthosis was never affixed to the ventral aspect of the fingertips.
The collected force sensor and accelerometer signals were visualized and inspected on a computer screen using the software program Matlab (version 7.12, The MathWorks Inc.; Natick, MA, USA). This program identified and measured the following variables: 1) Grip Force at the Moment of Lift-off (GFLO), which is the thumb-index pinch force applied at the instant the object leaves the surface of the table and represents anticipatory grip force control (planned forces)22; the moment of object lift-off was indicated by the acceleration signal; 2) Load Force Peak (LFP), defined as the maximum Load Force achieved during object lifting, calculated as LF¼m*(AccZ þ g)23,24 where Load Force Peak (LF) in Newtons (N) was calculated by multiplication of the object’s mass (m), in kilograms, by the addition of the recorded vertical acceleration (AccZ) and gravity (g).12 Because the tasks consisted of vertical lifting trials without object tilting, loading components acting in the direction of the applied grip forces (x-axis) and sagittal (y-axis) to it were not included in the calculation; 3) Grip Force Peak (GFP), defined as the maximum thumb-index pinch force achieved during object lifting, indicating somatosensory feedback-based grip force control during the dynamic phase (lifting)11; 4) Latency, calculated as the duration of time between the onset of thumb-index pinch force application and the moment of object lift-off from the table, which indicates the coordination of grip and load forces25; and 5) Static Force (SF), defined as the mean thumb-index pinch force from the point where movement velocity becomes approximately zero after the object’s vertical lifting to 4 s, when individuals were asked to hold it statically; this variable represents somatosensory feedback-based grip force control during the static phase (post lifting)11; the last second of the task was removed from analysis to ensure that all individuals were still in a static phase (Fig. 2). Statistical analysis Repeated measures analysis of variance (ANOVA) with a General Linear Model option (polynomial) was performed to compare the precision grip force control variables (GFLO, GFP, LFP, latency, and SF) across the five test conditions (UJM, RFF, MRF, RFE, MRE). Within subject correlation structure was taken to be compound symmetry, a standard choice. Post hoc analysis was performed to determine which pair or pairs of conditions were statistically different. The Bonferroni correction was used to adjust for multiple
Table 1 Normal range of motion and amount of applied restriction (means and standard deviations) Joint
Range of motion (degree)
PIP
Extensioneflexion 0e102
DIP
0e87.7
Percentage of restriction (%) SD
Flexion 45.78
SD 17.69
Extension 58.14
SD 16.24
29.65
15.38
51.54
14.56
34.39
20.61
44.31
18.11
Opponency 45.73
SD 5.9
Abduction 31.61
SD 4.21
4.14 7.99 IPT TMC
0e88.7 Opponency 0e36.6
SD 3.13
2.97 Abduction 0e44.6
SD 4.77
Proximal interphalangeal joint (PIP), distal interphalangeal joint (DIP), interphalangeal joint of thumb (IPT), and trapeziometacarpal joint (TMC).
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Force Peak (F ¼ 1.04, p ¼ 0.39) or Static Force (F ¼ 1.6, p ¼ 0.18) (Fig. 4). Discussion
Fig. 3. Means and standard errors for latency recorded under the following conditions: unrestricted joint movement (UJM); mock restricted flexion (MRF); mock restricted extension (MRE); restricted finger flexion (RFF); restricted finger extension (RFE). * represents a statistically-significant difference between RFE and UJM (p < 0.05). ** represents a statistically-significant difference between the RFE and MRF (p 0.05).
comparisons. SPSS software (Statistical Package for the Social Sciences, version 13.0) was used for all statistical analysis. The adopted significance level was p < 0.05 and all tests were twotailed.
Results The orthotic intervention we used to restrict the range of motion of finger joints was effective. The orthosis applied to the index and thumb finger joints caused clinically relevant limitations in all target joints (PIP, DIP, IPT, TMC) (Table 1). Repeated measures ANOVA identified latency as significantly different (F ¼ 4.41, p < 0.01) between the five conditions, with post hoc analysis detecting a significant increase in latency during RFE relative to two control conditions. In particular, Latency during RFE was significantly longer than with UJM (p < 0.01) and MRF (p ¼ 0.02) (Fig. 3). No statistically-significant differences between the conditions were noted for the other variables of precision grip force control: GFLO (F ¼ 2.03, p ¼ 0.1); Grip Force Peak (F ¼ 2.97, p ¼ 0.90); Load
In a recent study, patients with osteoarthritis of the hand were discovered to apply greater grip forces and exhibit increased latency while grasping and lifting a test object.16 Since these subjects had no deficits of tactile sensitivity in their fingertips, it was suggested that changes in their grip force control were caused by limited joint mobility of the fingers, due to erosion and edema, which is common in patients with hand osteoarthritis. However, in addition to important finger joint restrictions, these patients may experience other symptoms like pain, lost sensation, proprioceptive deficits, and muscular weakness, which also can affect grip force control.15 Consequently, the aim of the current study was to investigate the effects of isolated finger joint hypomobility on precision grip force control. To our knowledge, this is the first reported study to demonstrate that limited range of motion of the finger joints, in itself, can adversely affect thumb-index pinch force control. Our most striking result was that limited extension of the thumb and index fingers significantly increased latency while pinching and lifting the test object. Given that our study subjects were healthy and tested normal for sensitivity, this change in latency might be attributed to the restrictions in finger joint movement. Latency is considered a measure of coordination between the muscles of the hand used to grab an object, and the proximal muscles of the arm, which are used to lift and hold it without support.26,27 Others have investigated this variable, dividing latency into two phases, preload and load, which represent the time taken for grasp stabilization and the time needed to develop appropriate lifting forces, respectively. These two phases together (as latency) represent the temporal coordination of grip and load forces25 and are usually disrupted in neurologically-impaired patients; for example, those with hemiparesis,25,26 cerebellar dysfunction27,28 or Parkinson’s disease.8,29 Various factors might explain why changes in latency also have been observed in patients without neurological problems16 or in healthy individuals with isolated limited finger joint mobility. Decreased range of motion of the finger joints may cause
Fig. 4. Means and standard errors for load force peak, grip force at lift-off (GFLO), grip force peak and static force recorded under the following conditions: unrestricted joint movement (UJM), mock restricted flexion (MRF), mock restricted extension (MRE), restricted finger flexion (RFF), restricted finger extension (RFE).
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a biomechanical disadvantage grasping objects, which inherently makes tasks like holding and lifting them difficult. For instance, it is possible that joint restriction, especially of finger extension, makes individuals alter the placement of their fingers on the object, and adjusting their finger position could delay the lift. In fact, studies involving kinematic analysis of the finger joints have demonstrated that healthy individuals change their digit placement on objects to compensate for asymmetrical tangential forces while lifting an object with its center of mass deviated from the center.30,31 In one study by Fu et al, subjects learned to minimize the variability in compensatory torque by modulating digit force as a function of digit position. Therefore, in all likelihood, digit placement on objects contributes to better distribution of digit force in the case of asymmetric digit load forces30 or when ‘correct/usual’ placement is no longer available, as in the present study. Despite proper modulations in grip force, the time required to accomplish the grasping and lifting tasks was adversely affected, which could influence one’s functional capacity to grasp and lift objects. For example, a strong positive correlation between the Moberg Peak-Up Test (MPUT), a test used to evaluate manual dexterity, and latency has been identified in patients with osteoarthritis; i.e., the higher the latency, the more time individuals took to complete the MPUT.17 This suggests that limitations in finger range of motion increase latency that, in turn, leads to a decline in manual dexterity. Conversely, the finger movement restrictions imposed in this study did not affect any of the force control variables. For instance, the grip force at the moment of lift-off (GFLO), grip force peak (GFP), and static force (SF) were no different in any of the experimental conditions. This suggests that the central nervous system compensates for decreased movement of finger joints to adjust precision grip force adequately, both before (GFLO) and during the lift as feedback on weight and other forces are received (GFP and SF). In addition, the finger joint restrictions imposed in this study did not cause the subjects to significantly change their precision grip strategy (pinch type), which could generate changes in the variables of grip force control.32 Furthermore, it seems that the small changes induced by lengthening the muscles involved in our experimental task, in certain conditions, did not affect precision grip force control. It is known that changes in a muscle’s length influences the magnitude of tension that muscle generates.33 For example, Werremeyer and Cole34 demonstrated that different positions of the wrist that considerably alter the length of the extrinsic flexor and extensor muscles of the fingers, both in flexion and extension, lead to changes in precision grip force control in healthy subjects. Therefore, the differences in muscular length due to our orthotic intervention seem to be not substantial enough to induce changes in the force control variables. Limitations of this study and recommendations for future research Admittedly, our study has certain limitations that are important to mention. First, while the outcomes of this study provide important information on the effects of hypomobility on control of precision grip force, it might not be generalizable to clinic populations, given that this study was conducted only on healthy individuals. It is known, however, that patients suffering from musculoskeletal diseases, in addition to having joint hypomobility, often experience other associated symptoms like pain, swelling, proprioceptive deficits and muscular weakness. Including them in this study would have conflicted with our purpose of isolating joint hypomobility to determine its unique role in lost hand function. Clearly, further research to determine the relative importance of these diverse factors in precision grip force control is warranted. Second, our experimental task involved the precision grip force
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applied by the thumb and index finger. While this approach has been used in a number of studies involving healthy individuals and clinical populations,3,11,25,35 investigating the effect of hypomobility in all fingers of the hand using a device with five individual sensors might better demonstrate the effects of hand hypomobility on grip force control. Further studies are needed to address this issue. Conclusions To our knowledge, this is the first report demonstrating how limited range of motion of the finger joints adversely affects precision grip force control. More specifically, such limitations appear to mostly prolong the time between the beginning of applied thumb-index pinch force on an object and its lift-off. This, in essence, represents increased difficulty pinching and lifting objects promptly, which can adversely affect manual dexterity and cause limitations in any activities of daily living that involve object manipulation. Thus, treatment strategies that aim to restore range of motion in finger joints might improve the temporal aspects of precision grip force control and, consequently, manual dexterity. References 1. Johansson RS, Westling G. Coordinated isometric muscle commands adequately and erroneously programmed for the weight during lifting task with precision grip. Exp Brain Res. 1988;71(1):59e71. 2. Bensmail D, Sarfeld AS, Fink GR, Nowak DA. Intermanual transfer of sensorimotor memory for grip force when lifting objects: the role of wrist angulation. Clin Neurophysiol. 2010;121(3):402e407. 3. Johansson RS. Dynamic use of tactile afferent signals in control of dexterous manipulation. Adv Exp Med Biol. 2002;508:397e410. 4. Cole KJ, Abbs JH. Grip force adjustments evoked by load force perturbations of a grasped object. J Neurophysiol. 1988;60(4):1513e1522. 5. Johansson RS, Westling G. Roles of glabrous skin receptors and sensorimotor memory in automatic control of precision grip when lifting rougher or more slippery objects. Exp Brain Res. 1984;56(3):550e564. 6. Johansson RS, Westling G. Significance of cutaneous input for precise hand movements. Electroencephalogr Clin Neurophysiol Suppl. 1987;39:53e57. 7. de Gruijl JR, van der Smagt P, De Zeeuw CI. Anticipatory grip force control using a cerebellar model. Neuroscience. 2009;162(3):777e786. 8. Fellows SJ, Noth J, Schwarz M. Precision grip and Parkinson’s disease. Brain. 1998;121(Pt 9):1771e1784. 9. Iyengar V, Santos MJ, Ko M, Aruin AS. Grip force control in individuals with multiple sclerosis. Neurorehabil Neural Repair. 2009;23(8):855e861. 10. Hermsdörfer J, Hagl E, Nowak DA, Marquardt C. Grip force control during object manipulation in cerebral stroke. Clin Neurophysiol. 2003;114(5): 915e929. 11. Quaney BM, Perera S, Maletsky R, Luchies CW, Nudo RJ. Impaired grip force modulation in the ipsilesional hand after unilateral middle cerebral artery stroke. Neurorehabil Neural Repair. 2005;19(4):338e349. 12. Hermsdörfer J, Elias Z, Cole JD, Quaney BM, Nowak DA. Preserved and impaired aspects of feed-forward grip force control after chronic somatosensory deafferentation. Neurorehabil Neural Repair. 2008;22(4):374e384. 13. Lowe BD, Freivalds A. Effect of carpal tunnel syndrome on grip force coordination on hand tools. Ergonomics. 1999;42(4):550e564. 14. Seo NJ, Sindhu BS, Shechtman O. Influence of pain associated with musculoskeletal disorders on grip force timing. J Hand Ther. 2011;24(4):335e343. quiz 344. 15. Huysmans MA, Hoozemans MJ, Visser B, van Dieën JH. Grip force control in patients with neck and upper extremity pain and healthy controls. Clin Neurophysiol. 2008;119(8):1840e1848. 16. de Oliveira DG, Nunes PM, Aruin AS, Dos Santos MJ. Grip force control in individuals with hand osteoarthritis. J Hand Ther. 2011;24(4):345e354. quiz 355. 17. Nunes PM, Oliveira DG, Aruin AS, dos Santos MJ. Relationship between hand function and grip force control in women with hand osteoarthritis. J Rehabil Res Dev. 2012;49:12. 18. Moberg E. Objective methods for determining the functional value of sensibility in the hand. J Bone Jt Surg Br. 1958;40-B(3):454e476. 19. Altman R, Alarcón G, Appelrouth D, et al. The American college of rheumatology criteria for the classification and reporting of osteoarthritis of the hand. Arthritis Rheum. 1990;33(11):1601e1610. 20. Nowak DA, Hermsdörfer J. Selective deficits of grip force control during object manipulation in patients with reduced sensibility of the grasping digits. Neurosci Res. 2003;47(1):65e72. 21. Nowak DA, Hermsdörfer J, Glasauer S, Philipp J, Meyer L, Mai N. The effects of digital anaesthesia on predictive grip force adjustments during vertical movements of a grasped object. Eur J Neurosci. 2001;14(4):756e762.
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22. Gordon AM, Westling G, Cole KJ, Johansson RS. Memory representations underlying motor commands used during manipulation of common and novel objects. J Neurophysiol. 1993;69(6):1789e1796. 23. Hermsdörfer J, Hagl E, Nowak DA. Deficits of anticipatory grip force control after damage to peripheral and central sensorimotor systems. Hum Mov Sci. 2004;23(5):643e662. 24. Nowak DA, Glasauer S, Meyer L, Mait N, Hermsdörfer J. The role of cutaneous feedback for anticipatory grip force adjustments during object movements and externally imposed variation of the direction of gravity. Somatosens Mot Res. 2002;19(1):49e60. 25. Raghavan P, Krakauer JW, Gordon AM. Impaired anticipatory control of fingertip forces in patients with a pure motor or sensorimotor lacunar syndrome. Brain. 2006;129(Pt 6):1415e1425. 26. Aruin AS. Support-specific modulation of grip force in individuals with hemiparesis. Arch Phys Med Rehabil. 2005;86(4):768e775. 27. Fellows SJ, Ernst J, Schwarz M, Töpper R, Noth J. Precision grip deficits in cerebellar disorders in man. Clin Neurophysiol. 2001;112(10):1793e 1802.
28. Brandauer B, Timmann D, Häusler A, Hermsdörfer J. Influences of load characteristics on impaired control of grip forces in patients with cerebellar damage. J Neurophysiol. 2010;103(2):698e708. 29. Fellows SJ, Noth J. Grip force abnormalities in de novo Parkinson’s disease. Mov Disord. 2004;19(5):560e565. 30. Fu Q, Zhang W, Santello M. Anticipatory planning and control of grasp positions and forces for dexterous two-digit manipulation. J Neurosci. 2010;30(27): 9117e9126. 31. Salimi I, Hollender I, Frazier W, Gordon AM. Specificity of internal representations underlying grasping. J Neurophysiol. 2000;84(5):2390e2397. 32. McDonnell MN, Ridding MC, Flavel SC, Miles TS. Effect of human grip strategy on force control in precision tasks. Exp Brain Res. 2005;161(3):368e373. 33. Gordon AM, Huxley AF, Julian FJ. The variation in isometric tension with sarcomere length in vertebrate muscle fibres. J Physiol. 1966;184(1):170e192. 34. Werremeyer MM, Cole KJ. Wrist action affects precision grip force. J Neurophysiol. 1997;78(1):271e280. 35. Westling G, Johansson RS. Factors influencing the force control during precision grip. Exp Brain Res. 1984;53(2):277e284.
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JHT Read for Credit Quiz: #284
Record your answers on the Return Answer Form found on the tear-out coupon at the back of this issue or to complete online and use a credit card, go to JHTReadforCredit.com. There is only one best answer for each question. #1. The strength of grip force used to manipulate objects is mostly determined by a. force at the moment of lift off b. movement velocity and direction c. object’s characteristics and friction coefficient d. object’s velocity and t rajectory #2. Which of the grip force control variables below have been shown by previous studies to be adversely affected due to decreased mobility of the fingers joints a. latency b. grip force peak c. time lag d. time to grip force peak #3. Individuals with finger joint restriction, especially finger extension, showed prolonged latency during pinching and
lifting the instrumented object used in this study. The authors suggested this alteration can be attributed respectively to a. decreased sensitivity of the fingers tip and decreased proprioception b. proprioceptive deficits and increased pain c. asymmetrical tangential forces and increased rotator toques d. biomechanical disadvantage and unusual finger placement #4. The grip force control variable denominated latency represents a. somatosensory feedback-based grip force control b. anticipatory grip force control c. coordination between grip and load force d. compensatory grip force control #5. Limited ROM was found to not affect pinch control a. true b. false When submitting to the HTCC for re-certification, please batch your JHT RFC certificates in groups of 3 or more to get full credit.