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226 TEMPORAL–SPATIAL CHARACTERISTICS AND THE STRIDE LENGTH–CADENCE RELATIONSHIP OF PEOPLE WITH PROGRESSIVE SUPRANUCLEAR PALSY
Posters / Parkinsonism and Related Disorders 16S1 (2010) S11–S86
Results: Postural control in both axes was affected by sensory perturbation. PD exhibited continued postural deficits during REINTEGRATION following visual and proprioceptive perturbations. Constraining plot analysis to a two cluster solution revealed between-group spatiotemporal differences in postural control strategy. Conclusions: Composite tests and analyses of balance may target rehabilitation therapies for PD posture. 226 TEMPORAL–SPATIAL CHARACTERISTICS AND THE STRIDE LENGTH–CADENCE RELATIONSHIP OF PEOPLE WITH PROGRESSIVE SUPRANUCLEAR PALSY T. Egerton1 , R. Iansek1 , D.R. Williams2 . 1 Clinical Research Centre for Movement Disorders and Gait, Southern Health, 2 Faculty of Medicine (Neurosciences), Monash University, Melbourne, Australia Background and Aims: Gait changes are a feature of people with progressive supranuclear palsy (PSP). While clinical features can be similar in people with Parkinson’s Disease (PD), there are pathological differences with PSP and different brain regions subserving gait are affected. Systematically assessing the temporal– spatial characteristics of gait, and comparing to PD and healthy older adults (HOA), may identify distinguishing features of PSP and permit further understanding of normal gait control. Methods: Gait characteristics in PSP (n = 7) were recorded using a GAITRite® walkway system at a range of self-selected speeds. Data were compared to PD of similar disease duration (n = 8) and HOAs (n = 19). Mann–Whitney U tests were used to compare group medians. Results: The PSP group had reduced stride length (SL) but similar cadence at preferred speed compared with HOA (median SL 1.07 m v 1.39 m, p = 0.01). The PD group had a greater range of SLs than PSP, which may reflect the improvement gained from medications. Double support percentage of gait cycle (DS%) was increased in PSP compared with both PD (p = 0.01) and HOA (p = 0.001) (median DS% 32.6% vs 26.7% vs 22.4% respectively). Base width and stride-tostride variability data had greater between-individual variability, and differences between groups were not significant. Conclusions: People with PSP had consistently reduced SL for their cadences indicating an alteration in the gain of the normal SL– cadence relationship. Decreased postural stability is known to be a feature of PSP. Other gait changes found in this investigation suggest compensations to enhance postural stability, with increased DS% the most notable. 227 SLEEP INDUCED BY ELECTRICAL STIMULATION OF THE PEDUNCULOPONTINE NUCLEUS IN PARKINSON’S DISEASE PATIENTS M. Ferraye1,2 , I. Arnulf3,4 , V. Fraix1,2,5 , S. Chabardes ` 1,2,5 , L. Goetz1,2 , 2 1,2,5 1,2 1 A.-L. Benabid , P. Pollak , B. Debuˆ . INSERM, U836, Grenoble Institute of Neurosciences, France; 2 J. Fourier University, Grenoble, France; 3 Disorders Unit, Piti´e-Salpˆetri`ere Hospital, Paris, France; 4 INSERM, CRICM-UMR975, Paris, France; 5 University Hospital of Grenoble, Grenoble, France Background: The pedunculopontine nucleus (PPN) belongs to the reticular ascending arousal system. We studied the effects of PPN area (PPNa) stimulation on gait disorders in seven Parkinsonian patients with previous STN surgery. At one-year follow-up, while testing PPNa electrical parameters settings, four patients became very drowsy or even fell asleep at high-frequency stimulation. The effects of low- and high-frequency stimulation on vigilance were tested. Methods: Daytime sleepiness was assessed in all patients using the Epworth daytime sleepiness scale. Two of the four patients were tested off medication during daytime video-polysomnography. Five to 10-min PPNa stimulation conditions [off, unilateral and
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bilateral on, at low (15–25 Hz) and high (60–80 Hz) frequencies] were randomly applied, repeated, in a double-blind manner, with 3-min washout periods in between, while patients resisted sleep or not. Results: In six patients, sleepiness was lower under low- than under high-frequency stimulation. The two patients studied by video-polysomnography were fully alert and spontaneously active under low-frequency unior bi-lateral PPNa stimulation. Conversely, uni- or bi-lateral high-frequency PPNa stimulation caused a marked feeling of sleepiness and induced 0.5 to 10 min episodes of behavioral and electrophysiological non rapid eye movement sleep stage N1, and more rarely stage N2. Switching PPNa off was consistently followed by rapid eye movement sleep episodes in one patient. Conclusions: Electrical stimulation of the PPNa can change alertness and sleep, corroborating physiological studies in animals. Thus, gait improvement following low-frequency PPNa stimulation might partly rest on increased alertness. 228 A METHODOLOGY FOR ASSESSING RISK OF FALLING BASED ON DATA FROM WEARABLE SENSORS E. Sazonov1 , Z. Sun1 , S. Zeigler2 , S. Marocco2 , G. Fulk2 . 1 Electrical and Computer Engineering, 2 Physical Therapy, Clarkson University, Potsdam, NY, USA Description and Aims: Postural control and falls risk can be assessed using a variety of different methods from the complex (forceplate and kinematic data) to more simple functional measures (Berg Balance Scale, BBS, or Timed Up and Go, TUG). Neither of these methods provides information regarding falls risk during potential high-risk behaviors in an individual’s natural environment. The purpose of this study was to test a sensor-based methodology for identifying elders who are at risk for falls. Methods: 9 individuals >60 living in an independent living community completed two clinical falls risk tools (BBS and TUG) while wearing sensors that detected plantar pressures, heel and body sway accelerations. They also completed the Activitiesspecific Balance Confidence Scale (ABC). Subjects were identified as at risk (AR) or not at risk (NR) of fall based on BBS, TUG and ABC scores. Differences in sensor signal patterns between the two groups were compared. Results: Significant differences (p < 0.05) between AR and NR of fall groups were found with anterior–posterior body sway during eyes closed, duration of weight transfer and weight bearing on the stool leg during alternate foot on stool, and duration of swing and stance phase, stride length and ratio of swing to stance with walking. Conclusions: Using plantar pressure, heel acceleration and body sway acceleration a shoe and body based sensor was able to differentiate between elders who were AR and NR for falls. This sensor may be able to detect falls risk in elders as they function in their natural environment. 229 GAIT AND POSTURE STRATEGY IN PERSONS WITH DOWN SYNDROME DURING THEIR LIFESPAN G. Albertini1 , C. Rigoldi2 , L. Mainardi2 , G. Santambrogio2 , M. Galli2 . 1 IRCCS ‘San Raffaele Pisana’, TOSINVEST Sanita, San Raffaele SPA, Roma, 2 Bioengineering Department, Politecnico di Milano, Milan, Italy Background and Aims: Individuals with Down syndrome (DS) have a myriad of factors thought to inhibit their locomotion skills. All these types of impairments contribute in large manner to the development of different components of motor behavior that lead to difficulties in motion and posture in everyday life. The aim of the study was to analyze the evolution of gait and posture strategies of subjects with DS during their lifespan. Methods: Data on 37 children, 58 teenagers and 45 adults with DS were collected. Posture data were collected asking subjects to
Results: Postural control in both axes was affected by sensory perturbation. PD exhibited continued postural deficits during REINTEGRATION following visual and proprioceptive perturbations. Constraining plot analysis to a two cluster solution revealed between-group spatiotemporal differences in postural control strategy. Conclusions: Composite tests and analyses of balance may target rehabilitation therapies for PD posture. 226 TEMPORAL–SPATIAL CHARACTERISTICS AND THE STRIDE LENGTH–CADENCE RELATIONSHIP OF PEOPLE WITH PROGRESSIVE SUPRANUCLEAR PALSY T. Egerton1 , R. Iansek1 , D.R. Williams2 . 1 Clinical Research Centre for Movement Disorders and Gait, Southern Health, 2 Faculty of Medicine (Neurosciences), Monash University, Melbourne, Australia Background and Aims: Gait changes are a feature of people with progressive supranuclear palsy (PSP). While clinical features can be similar in people with Parkinson’s Disease (PD), there are pathological differences with PSP and different brain regions subserving gait are affected. Systematically assessing the temporal– spatial characteristics of gait, and comparing to PD and healthy older adults (HOA), may identify distinguishing features of PSP and permit further understanding of normal gait control. Methods: Gait characteristics in PSP (n = 7) were recorded using a GAITRite® walkway system at a range of self-selected speeds. Data were compared to PD of similar disease duration (n = 8) and HOAs (n = 19). Mann–Whitney U tests were used to compare group medians. Results: The PSP group had reduced stride length (SL) but similar cadence at preferred speed compared with HOA (median SL 1.07 m v 1.39 m, p = 0.01). The PD group had a greater range of SLs than PSP, which may reflect the improvement gained from medications. Double support percentage of gait cycle (DS%) was increased in PSP compared with both PD (p = 0.01) and HOA (p = 0.001) (median DS% 32.6% vs 26.7% vs 22.4% respectively). Base width and stride-tostride variability data had greater between-individual variability, and differences between groups were not significant. Conclusions: People with PSP had consistently reduced SL for their cadences indicating an alteration in the gain of the normal SL– cadence relationship. Decreased postural stability is known to be a feature of PSP. Other gait changes found in this investigation suggest compensations to enhance postural stability, with increased DS% the most notable. 227 SLEEP INDUCED BY ELECTRICAL STIMULATION OF THE PEDUNCULOPONTINE NUCLEUS IN PARKINSON’S DISEASE PATIENTS M. Ferraye1,2 , I. Arnulf3,4 , V. Fraix1,2,5 , S. Chabardes ` 1,2,5 , L. Goetz1,2 , 2 1,2,5 1,2 1 A.-L. Benabid , P. Pollak , B. Debuˆ . INSERM, U836, Grenoble Institute of Neurosciences, France; 2 J. Fourier University, Grenoble, France; 3 Disorders Unit, Piti´e-Salpˆetri`ere Hospital, Paris, France; 4 INSERM, CRICM-UMR975, Paris, France; 5 University Hospital of Grenoble, Grenoble, France Background: The pedunculopontine nucleus (PPN) belongs to the reticular ascending arousal system. We studied the effects of PPN area (PPNa) stimulation on gait disorders in seven Parkinsonian patients with previous STN surgery. At one-year follow-up, while testing PPNa electrical parameters settings, four patients became very drowsy or even fell asleep at high-frequency stimulation. The effects of low- and high-frequency stimulation on vigilance were tested. Methods: Daytime sleepiness was assessed in all patients using the Epworth daytime sleepiness scale. Two of the four patients were tested off medication during daytime video-polysomnography. Five to 10-min PPNa stimulation conditions [off, unilateral and
S65
bilateral on, at low (15–25 Hz) and high (60–80 Hz) frequencies] were randomly applied, repeated, in a double-blind manner, with 3-min washout periods in between, while patients resisted sleep or not. Results: In six patients, sleepiness was lower under low- than under high-frequency stimulation. The two patients studied by video-polysomnography were fully alert and spontaneously active under low-frequency unior bi-lateral PPNa stimulation. Conversely, uni- or bi-lateral high-frequency PPNa stimulation caused a marked feeling of sleepiness and induced 0.5 to 10 min episodes of behavioral and electrophysiological non rapid eye movement sleep stage N1, and more rarely stage N2. Switching PPNa off was consistently followed by rapid eye movement sleep episodes in one patient. Conclusions: Electrical stimulation of the PPNa can change alertness and sleep, corroborating physiological studies in animals. Thus, gait improvement following low-frequency PPNa stimulation might partly rest on increased alertness. 228 A METHODOLOGY FOR ASSESSING RISK OF FALLING BASED ON DATA FROM WEARABLE SENSORS E. Sazonov1 , Z. Sun1 , S. Zeigler2 , S. Marocco2 , G. Fulk2 . 1 Electrical and Computer Engineering, 2 Physical Therapy, Clarkson University, Potsdam, NY, USA Description and Aims: Postural control and falls risk can be assessed using a variety of different methods from the complex (forceplate and kinematic data) to more simple functional measures (Berg Balance Scale, BBS, or Timed Up and Go, TUG). Neither of these methods provides information regarding falls risk during potential high-risk behaviors in an individual’s natural environment. The purpose of this study was to test a sensor-based methodology for identifying elders who are at risk for falls. Methods: 9 individuals >60 living in an independent living community completed two clinical falls risk tools (BBS and TUG) while wearing sensors that detected plantar pressures, heel and body sway accelerations. They also completed the Activitiesspecific Balance Confidence Scale (ABC). Subjects were identified as at risk (AR) or not at risk (NR) of fall based on BBS, TUG and ABC scores. Differences in sensor signal patterns between the two groups were compared. Results: Significant differences (p < 0.05) between AR and NR of fall groups were found with anterior–posterior body sway during eyes closed, duration of weight transfer and weight bearing on the stool leg during alternate foot on stool, and duration of swing and stance phase, stride length and ratio of swing to stance with walking. Conclusions: Using plantar pressure, heel acceleration and body sway acceleration a shoe and body based sensor was able to differentiate between elders who were AR and NR for falls. This sensor may be able to detect falls risk in elders as they function in their natural environment. 229 GAIT AND POSTURE STRATEGY IN PERSONS WITH DOWN SYNDROME DURING THEIR LIFESPAN G. Albertini1 , C. Rigoldi2 , L. Mainardi2 , G. Santambrogio2 , M. Galli2 . 1 IRCCS ‘San Raffaele Pisana’, TOSINVEST Sanita, San Raffaele SPA, Roma, 2 Bioengineering Department, Politecnico di Milano, Milan, Italy Background and Aims: Individuals with Down syndrome (DS) have a myriad of factors thought to inhibit their locomotion skills. All these types of impairments contribute in large manner to the development of different components of motor behavior that lead to difficulties in motion and posture in everyday life. The aim of the study was to analyze the evolution of gait and posture strategies of subjects with DS during their lifespan. Methods: Data on 37 children, 58 teenagers and 45 adults with DS were collected. Posture data were collected asking subjects to