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P389 Three-dimensional movement analysis of hand function in preschool children
Poster Session: Motor Control HOMOGENEOUS AND MODULATED SEGMENTS IN EEG PRIOR TO VOLUNTARY MOVEMENTS R. Draganova. Institute of Physiology, Sofia, Bulgaria
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367
MODULATIONOF THE QUADRICEPS TENDON JERK REFLEX DURING GAIT IN HEMISPASTICPATIENTS
M. Faist, M. Ertel, W. Berger. Department of Clinical Neurology and Neurophysiology, University of Freiburg, Germany
Two methods for separating the homogeneous and modulated segments in EEG prior to voluntary movements were investigated. The method of linear transformation allows for eliciting harmonic components preserving their shape and initial phase and was used for recognizing the possible carrier (CF) and side-band frequencies participating in the modulation process. In many cases the modulation frequencies are wrongly interpreted as particular harmonic components. With this method it could be deference the type of modulation, i,e. amplitude (AM) or frequency (FM), and distinguish between modulation and additive components. The method of complex demodulation was used for confirming the availability of FM or AM by tracking the time-dependant changes in the amplitude and phase of a particular frequency component, in this case, the determined CE The method is also suitable for nonstationary processes. Segments with homogenous frequency contents as well as changes in time of a given frequency (CF) were found in the EEG signals before voluntary finger movements, recorded from the supplementary and primary motor areas. Thus the movement preparatory process consists of consecutive phases with different dynamic structure. The way of tracking their onset and development was shown.
~-8"9-] THREE-DIMENSIONALMOVEMENT ANALYSIS OF HAND FUNCTION IN PRESCHOOL CHILDREN
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R. Blank, S. Flett, W. Hcizer. Kinderzentrum Miinchen, Abt. Klinische Neurophysiologie, Heiglhofstr. 63, 81377 Miinchen, Germany
KINEMATICANALYSIS OF HAND MOVEMENTS DURING PAINTING IN PRESCHOOL CHILDREN
R. Blank, N. Pill. Kinderzentrum Miinchen, Abt. Klinische
Neurophysiologie, Heiglhofstr 63, 81377 Miinchen, German). The use of a pencil is one of the highest fine motor function. The development of this ability mainly takes place during preschool age. This is the basis for fluent writing in elementary school. The kinematics of pencil movements were examined by a commercial digitizer tablet and a special analysing software. Different patterns of elementary und complex movements had to be carried out. The results showed typical developmental differences in controlled and automatic motor processes. The patterns of healthy children showed striking differences to children with disorders of motor functions. This diagnostic tool may be used in combination with or in addition to EMG or evoked potentials in order to elicit the development of motor control.
-P-3~
MODULATION OF RECURRENT INHIBITION IN SOLEUS AND TIBIALIS ANTERIOR MUSCLE DURING HUMAN GAIT
Modulation of the quadriceps tendon jerk reflex was investigated during the stepcycle in 10 hemiparetic patients and 10 healthy control subjects. Reflexes were evoked by a tendon tap during treadmill walking. In healthy subjects a clear modulation of the tendon reflex can be observed. A similar pattern of modulation of the H-reflex during gait has been ascribed at least partly to modulation of presynaptic inhibition. In the hemiparetic patients there was no or only a weak modulation of the tendon reflex amplitude on the affected side and a stronger modulation on the unaffected side with a larger variance of the results compared to healthy subjects. In a previous study it has been shown that in hemispastie patients the tonic level of presynaptic inhibition of la afferents to soleus seems to be unaffected at rest. It is argued that this lack of reflex modulation in hemiparetic patients during locomotion could reflect a reduced or disturbed supraspinal modulation of presynaptic inhibition of la afferents to quadriceps during a functional task.
In preschool age dramatic development of distinct hand functions take place. So far, the hand function of children was mainly examined by qualitative or semi-quantitative methods. Quantitative movement analysis became feasable with the technical development of information processing. With an ultrasound based system, elementary and complex motor functions of the hand were examined in preschool children (3 to 5 years). The following functions were examined: l. tapping of finger and hand, 2. aiming to nose and to an object, 3. repetitive movements up and down as well as back and forward (with defined grip object), 4. grasping, 5. producing different serial movements in special order (serial praxia), 6. imitating gestures (ideomotor praxia). The results show clear age dependent differences. Further, healthy children and children with movement disorders could be differentiated. The children develop automatic and controlled movement patterns which show typical general and individual profiles for speed, acceleration and for precision. The profiles can be used for differential diagnostic purposes. As the instruments can be combined with EMG and EEG new insight of the development of hand function may be expected.
M. Faist, C. Blahak, W. Berger. Department of Clinical Neurology and
Neurophysiology, University of Freiburg, Germany Modulation of recurrent inhibition from quadriceps onto soleus (SOL) and tibialis anterior (TA) motoneurons was investigated during treadmill walking in 12 healthy subjects and compared to the level of inhibition obtained during tonic voluntary contraction. We used averaged unrectified and rectified EMG of SOL and TA conditioned by a supramaximal stimulation of the femoral nerve. The inhibition (lasting 20-40 ms) that follows the monosynaptic Ia-facilitation in both muscles is argued 'to be most likely recurrent inhibition. During the stepcycle there was a clear phase dependent modulation of this inhibition which was not simply dependent on the EMG activity of the respective muscle. In SOL there was a clear reduction of the inhibition at the transition from swing to stance and at the end of the stance phase but an unchanged level during the stance phase. In TA inhibition was strongly reduced at the beginning and at the end of the swing phase and reached the control level only in the middle of the swing phase. It is argued that the observed modulation of recurrent inhibition could play a role in activating the leg muscles in a characteristic pattern during gait. Abnormalities of this control could contribute to disturbances of motor control.
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EFFECT OF THALAMIC STIMULATION ON GAIT IN PARKINSON'S DISEASE
L. Defebvre 1,4, J.L. Blatt 2,4, S. Blond 3.4, J.L. Bourriez 2,4, J.D. Guieu 2,4, A. Destte 1.4. i Department of Neurology, Lille, France; 2 Department of
Neurophysiology, Lille, France; 3 Department of Neurosurgery, Lille, France; 4 Department of Gait Analysis, Lille, France The thalamic stimulation of the ventralis intermedialis (Vim) nucleus has been proposed for the treatment of refractory parkinsonian tremor. The effect of thalamic stimulation on gait disturbances is still discussed. The aim of the study was to evaluate the influence of thalamic stimulation on gait in Parkinson's disease. Seven patients who had a thalamic stimulation of the Vim nucleus to control a large amplitude tremor were studied. The gait kinematic parameters were automatically recorded using optoelectric Vicon system for movements analysis. Measures of locomotor displacements: cadence, walking speed, stride and step times, single and double supports, stride and step lengths were computed successively during two conditions: stimulation on and off. Traces of ankle joint position were also analyzed for the left and the right lower limbs and the affected and unaffected lower limbs. No difference of the mean values between the two conditions were observed both for the local displacements and the ankle joint positions. This
•
367
MODULATIONOF THE QUADRICEPS TENDON JERK REFLEX DURING GAIT IN HEMISPASTICPATIENTS
M. Faist, M. Ertel, W. Berger. Department of Clinical Neurology and Neurophysiology, University of Freiburg, Germany
Two methods for separating the homogeneous and modulated segments in EEG prior to voluntary movements were investigated. The method of linear transformation allows for eliciting harmonic components preserving their shape and initial phase and was used for recognizing the possible carrier (CF) and side-band frequencies participating in the modulation process. In many cases the modulation frequencies are wrongly interpreted as particular harmonic components. With this method it could be deference the type of modulation, i,e. amplitude (AM) or frequency (FM), and distinguish between modulation and additive components. The method of complex demodulation was used for confirming the availability of FM or AM by tracking the time-dependant changes in the amplitude and phase of a particular frequency component, in this case, the determined CE The method is also suitable for nonstationary processes. Segments with homogenous frequency contents as well as changes in time of a given frequency (CF) were found in the EEG signals before voluntary finger movements, recorded from the supplementary and primary motor areas. Thus the movement preparatory process consists of consecutive phases with different dynamic structure. The way of tracking their onset and development was shown.
~-8"9-] THREE-DIMENSIONALMOVEMENT ANALYSIS OF HAND FUNCTION IN PRESCHOOL CHILDREN
~-~
R. Blank, S. Flett, W. Hcizer. Kinderzentrum Miinchen, Abt. Klinische Neurophysiologie, Heiglhofstr. 63, 81377 Miinchen, Germany
KINEMATICANALYSIS OF HAND MOVEMENTS DURING PAINTING IN PRESCHOOL CHILDREN
R. Blank, N. Pill. Kinderzentrum Miinchen, Abt. Klinische
Neurophysiologie, Heiglhofstr 63, 81377 Miinchen, German). The use of a pencil is one of the highest fine motor function. The development of this ability mainly takes place during preschool age. This is the basis for fluent writing in elementary school. The kinematics of pencil movements were examined by a commercial digitizer tablet and a special analysing software. Different patterns of elementary und complex movements had to be carried out. The results showed typical developmental differences in controlled and automatic motor processes. The patterns of healthy children showed striking differences to children with disorders of motor functions. This diagnostic tool may be used in combination with or in addition to EMG or evoked potentials in order to elicit the development of motor control.
-P-3~
MODULATION OF RECURRENT INHIBITION IN SOLEUS AND TIBIALIS ANTERIOR MUSCLE DURING HUMAN GAIT
Modulation of the quadriceps tendon jerk reflex was investigated during the stepcycle in 10 hemiparetic patients and 10 healthy control subjects. Reflexes were evoked by a tendon tap during treadmill walking. In healthy subjects a clear modulation of the tendon reflex can be observed. A similar pattern of modulation of the H-reflex during gait has been ascribed at least partly to modulation of presynaptic inhibition. In the hemiparetic patients there was no or only a weak modulation of the tendon reflex amplitude on the affected side and a stronger modulation on the unaffected side with a larger variance of the results compared to healthy subjects. In a previous study it has been shown that in hemispastie patients the tonic level of presynaptic inhibition of la afferents to soleus seems to be unaffected at rest. It is argued that this lack of reflex modulation in hemiparetic patients during locomotion could reflect a reduced or disturbed supraspinal modulation of presynaptic inhibition of la afferents to quadriceps during a functional task.
In preschool age dramatic development of distinct hand functions take place. So far, the hand function of children was mainly examined by qualitative or semi-quantitative methods. Quantitative movement analysis became feasable with the technical development of information processing. With an ultrasound based system, elementary and complex motor functions of the hand were examined in preschool children (3 to 5 years). The following functions were examined: l. tapping of finger and hand, 2. aiming to nose and to an object, 3. repetitive movements up and down as well as back and forward (with defined grip object), 4. grasping, 5. producing different serial movements in special order (serial praxia), 6. imitating gestures (ideomotor praxia). The results show clear age dependent differences. Further, healthy children and children with movement disorders could be differentiated. The children develop automatic and controlled movement patterns which show typical general and individual profiles for speed, acceleration and for precision. The profiles can be used for differential diagnostic purposes. As the instruments can be combined with EMG and EEG new insight of the development of hand function may be expected.
M. Faist, C. Blahak, W. Berger. Department of Clinical Neurology and
Neurophysiology, University of Freiburg, Germany Modulation of recurrent inhibition from quadriceps onto soleus (SOL) and tibialis anterior (TA) motoneurons was investigated during treadmill walking in 12 healthy subjects and compared to the level of inhibition obtained during tonic voluntary contraction. We used averaged unrectified and rectified EMG of SOL and TA conditioned by a supramaximal stimulation of the femoral nerve. The inhibition (lasting 20-40 ms) that follows the monosynaptic Ia-facilitation in both muscles is argued 'to be most likely recurrent inhibition. During the stepcycle there was a clear phase dependent modulation of this inhibition which was not simply dependent on the EMG activity of the respective muscle. In SOL there was a clear reduction of the inhibition at the transition from swing to stance and at the end of the stance phase but an unchanged level during the stance phase. In TA inhibition was strongly reduced at the beginning and at the end of the swing phase and reached the control level only in the middle of the swing phase. It is argued that the observed modulation of recurrent inhibition could play a role in activating the leg muscles in a characteristic pattern during gait. Abnormalities of this control could contribute to disturbances of motor control.
~-~
EFFECT OF THALAMIC STIMULATION ON GAIT IN PARKINSON'S DISEASE
L. Defebvre 1,4, J.L. Blatt 2,4, S. Blond 3.4, J.L. Bourriez 2,4, J.D. Guieu 2,4, A. Destte 1.4. i Department of Neurology, Lille, France; 2 Department of
Neurophysiology, Lille, France; 3 Department of Neurosurgery, Lille, France; 4 Department of Gait Analysis, Lille, France The thalamic stimulation of the ventralis intermedialis (Vim) nucleus has been proposed for the treatment of refractory parkinsonian tremor. The effect of thalamic stimulation on gait disturbances is still discussed. The aim of the study was to evaluate the influence of thalamic stimulation on gait in Parkinson's disease. Seven patients who had a thalamic stimulation of the Vim nucleus to control a large amplitude tremor were studied. The gait kinematic parameters were automatically recorded using optoelectric Vicon system for movements analysis. Measures of locomotor displacements: cadence, walking speed, stride and step times, single and double supports, stride and step lengths were computed successively during two conditions: stimulation on and off. Traces of ankle joint position were also analyzed for the left and the right lower limbs and the affected and unaffected lower limbs. No difference of the mean values between the two conditions were observed both for the local displacements and the ankle joint positions. This