Plasma homocysteine levels in patients treated with levodopa: motor and cognitive associations.
OBJECTIVE
The aim of this study was to determine whether hyperhomocysteinemia caused by levodopa used in idiopathic Parkinson's disease (IPD) is associated with cognitive or physical impairments. The role of folate and vitamin B12 levels in this context was also ascertained.


METHODS
Thirty-nine patients who had been followed with the diagnosis of IPD in our clinic for > 2 years and 28 healthy control subjects with similar demographic features were included in the study. The homocysteine, folic acid and vitamin B12 levels and the results of the short test of mental status (STMS) and the clock drawing test of IPD patients were compared with those of the controls. Subsequently, the patients with a homocysteine level of >14 micromol/l were compared with those having a homocysteine level of <14 micromol/l by means of detailed neuropsychometric test batteries.


RESULTS
Homocysteine levels were significantly higher in the patient group in comparison with the controls. There was a negative correlation between hyperhomocysteinemia and the levels of vitamin B12 and folate. On the other hand, a positive correlation between hyperhomocysteinemia and the levodopa dose was detected. There was a positive correlation between hyperhomocysteinemia and unified Parkinson's disease rating scale (UPDRS) motor section. The critical dose of levodopa was observed to be 300 mg/d. In terms of cognitive and frontal functions, no significant difference was detected between the patients and control group. The subgroup with a homocysteine level of >14 micromol/l had a significantly poorer performance in frontal and memory tests.


CONCLUSIONS
In patients with IPD who are detected to have hyperhomocysteinemia, the assessment of the cognitive performance, folic acid and vitamin B12 levels and the supplementation of folic acid and vitamin B12 to the treatment regimen might be appropriate.
Ozer
Feriha
F
Department of Neurology, Haseki Educational and Research Hospital, Turkey. ffozer@yahoo.com
Meral
Hasan
H
Hanoglu
Lutfu
L
Aydemir
Tuba
T
Yilsen
Meral
M
Cetin
Sibel
S
Ozturk
Oya
O
Seval
Hatice
H
Koldas
Macit
M
D000368:Aged; D000369:Aged, 80 and over; D000978:Antiparkinson Agents / Q000009:adverse effects*; D016022:Case-Control Studies; D003071:Cognition / Q000187:drug effects*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005492:Folic Acid / Q000097:blood; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007980:Levodopa / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000187:drug effects*; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology; D018709:Statistics, Nonparametric; D014805:Vitamin B 12 / Q000097:blood
D000978:Antiparkinson Agents; D006710:Homocysteine; D007980:Levodopa; D005492:Folic Acid; D014805:Vitamin B 12