Abstract:
We investigated the likelihood that hypokinesia/bradykinesia coexist with druginduced
dyskinesias (DID) in patients with Parkinson's disease (PD). The influence of
dyskinesias on rapid alternating movements (RAM) was investigated in ten dyskinetic
patients (DPD). Their motor performance was compared to that of ten age/gendermatched
non-dyskinetic patients (NDPD) and ten healthy control subjects. Whole-body
magnitude (WBM) and fast pronation-supination at the wrist were recorded using 6-
degrees of freedom magnetic motion tracker and forearm rotational sensors, respectively.
Subjects were asked to pronate-supinate their dominant hand for 10s. Pre- and postmeasures
were taken in a neutral position for 20s. RANGE (measure of hypokinesia),
DURATION (measure of bradykinesia). VELOCITY (measure of bradykinesia) and
IRREGULARITY (measure of fluctuations in movement amplitude) were used to assess
RAM performance. Results showed that DPD patients had greater WBM than NDPD and
control groups during rest and RAM performance. There were no differences in
performance between NDPD and DPD groups for RANGE, DURATION and
VELOCITY, despite significant longer disease duration for the DPD group (DPD = 15.5
± 6.2 years versus NDPD = 6.6 ± 2.6 years). However, both the NDPD and DPD groups
showed lower RANGE, longer DURATION, and reduced VELOCITY compared to
controls,, suggesting the presence of bradykinesia and hypokinesia. In the case of
IRREGULARITY, DPD patients showed clear fluctuations in movement amplitude
compared to the NDPD and control groups. However, the lack of correlation between
WBM and IRREGULARITY within the DPD group (Spearman's rank order, Rho - 0.31,
p > 0.05), suggests that DID was not the primary cause of the fluctuating movementamplitude observed in that group. In conclusion, these findings suggest that DID may
coexists with bradykinesia and hypokinesia, but that they are not inevitably accompanied
with worsening motor performance.
