Pallidal deep brain stimulation and L-dopa do not improve qualitative aspects of skilled reaching in Parkinson's disease.
OBJECTIVE
To determine effects of dopaminergic medication and pallidal deep brain stimulation (DBS) on skilled reach in Parkinson's disease (PD).


BACKGROUND
PD is a neurodegenerative disorder affecting motor control. While speed and execution of movements are improved by L-dopa, not all motor symptoms are alleviated. Little is known about the effects of DBS or medication on reaching.


METHODS
Eight PD patients with unilateral pallidal DBS reached with the contra-lateral hand for a piece of food, placing it in the mouth, and returning to starting position. Testing was performed on no treatment, medication only, DBS only, and combined treatment. Reaches were digitally recorded and analyzed on a 21 point scale adapted from Eshkol-Wachman Notation. Analysis was blinded, with patients compared to age-matched controls.


RESULTS
Patients were tested 6-13 months after surgery. All showed significant improvement clinically and in UPDRS (III) scores. The following data were obtained on the reaching scale: normal controls 16.5-21.0 (mean 18.3), no treatment 3.0-12.5 (mean 7.4), medication only 7.0-14.0 (mean 10.3), DBS only 4.5-16.0 (mean 9.2), combined treatment 4.0-15.0 (mean 9.5). The difference between controls and all treatment groups was statistically significant (P<0.005). All aspects of reach were compromised. No significant differences were found among the four conditions.


CONCLUSIONS
This study is consistent with accumulating evidence that some aspects of motor performance in PD patients, such as reaching, are resistant to L-dopa. Also, pallidal DBS does not improve those parameters that are resistant to L-dopa, either alone or in combination with medication.
Melvin
Kyle G
KG
Department of Clinical Neurosciences, Faculty of Medicine, Movement Disorders Program, Foothills Hospital, University of Calgary, Area 33350, Hospital Dr NW, Calgary, Alta., Canada T2N 4N1. kgmelvin@ucalgary.ca
Doan
Jon
J
Pellis
Sergio M
SM
Brown
Lesley
L
Whishaw
Ian Q
IQ
Suchowersky
Oksana
O
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000978:Antiparkinson Agents / Q000627:therapeutic use*; D016022:Case-Control Studies; D046690:Deep Brain Stimulation / Q000379:methods*; D005500:Follow-Up Studies; D007839:Functional Laterality; D005917:Globus Pallidus / Q000187:drug effects / Q000503:physiopathology / Q000528:radiation effects; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use*; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology / Q000628:therapy*; D011446:Prospective Studies; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D018709:Statistics, Nonparametric; D016896:Treatment Outcome
D000978:Antiparkinson Agents; D007980:Levodopa