[Abstract Title]. - Society for Neuroscience

Poster
272. Kinematics and EMG: Diseases
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 272.7/II6
Topic: D.12.b. Diseases
Support: Creighton University School of Pharmacy and Health Professions Faculty
Development Grant
Title: Quantitative relationship between bradykinesia and rigidity in Parkinson‟s disease
Authors: *R. XIA 1 , H. HAIDER 2 ;
1 Dept of Physical Therapy, Creighton Univ., Omaha, NE; 2 Dept. of Orthopaedic Surgery and
Rehabil., Univ. of Nebraska Med. Ctr., Omaha, NE
Abstract: Bradykinesia and rigidity are primary motor symptoms in Parkinson‟s disease (PD).
Both symptoms are responsive to therapeutic treatment. Thus, bradykinesia and rigidity are used
as criteria for clinical diagnosis and as tools for evaluating the efficacy of treatment. The
objective of this study was to examine the relationship between bradykinesia and rigidity using
physiological and biomechanical quantification of the two symptoms. Five subjects with PD
participated in the study under a temporary withdrawal from the treatment. Subject‟s more
impaired hand was tested while each subject sat on an adjustable chair. To assess bradykinesia,
subjects were instructed to perform voluntary wrist flexion and extension movements, from 30°
extended position to 30° flexed position and back to original position, for 10 seconds. Each
subject conducted movements either at the fastest pace or by following a metronome at 0.4 Hz.
Subjects were provided with visual feedback regarding their wrist positions. To evaluate rigidity,
a servomotor generated wrist flexion and extension movement within the same range of motion
at 50°/sec and 280°/sec. Joint position, wrist torque and electromyograms (EMGs) of the flexor
and extensor muscles of the wrist and fingers were recorded during both voluntary and
servomotor-induced movements. Bradykinesia was quantified by the number of voluntary
flexion/extension cycles completed within 10s duration. Performance of the voluntary movement
was assessed by the movement error, measured as average degree of over- and under-shooting
compared to peak amplitude (30°). Rigidity was measured by integrating torque resistance with
time during movement phases. Pearson‟s correlation coefficients were calculated between
variables characterizing bradykinesia and rigidity. Moderate correlations exist between
movement error and torque integral (r = 0.682 for the slower motion; r = 0.564 for the faster
one). Correlation between the number of movement cycle and torque integral was r = -0.424
(applicable for the faster movement only). Pilot data suggest that there are correlations between