Dopaminergic dysfunction in midbrain dystonia: anatomoclinical study using 3-dimensional magnetic resonance imaging and fluorodopa F 18 positron emission tomography.
OBJECTIVE
To determine the role of damage to neuronal systems, especially the dopaminergic system, in patients with symptomatic dystonia and mesencephalic lesions.


METHODS
Stereotaxic magnetic resonance imaging analysis and positron emission tomography after the administration of fluorodopa F 18.


METHODS
Of a group of 48 patients with unilateral dystonia following a stroke, 7 patients with a well-defined midbrain lesion were selected.


RESULTS
All patients had unilateral dystonic posture of an upper extremity and cerebellar dysmetria or hypotonia. Cerebellar tremor was present in 1 patient. Two patients had resting and postural tremor, which showed a marked improvement with treatment with levodopa. In patients with dystonia only, dopaminergic lesions were mostly confined to the ventromesial mesencephalon and red nucleus area, including the substantia nigra and nigrostriatal and cerebellothalamic fibers. Dystonia was severe and did not resolve with time in patients with lesions involving the nigrostriatal pathway, and the degree of dopaminergic denervation revealed by positron emission tomography was correlated with the severity of dystonia. In patients with resting and postural tremor, lesions of the dopaminergic structures were larger and located more laterally and dorsally in the pars compacta, the perirubral and retrorubral areas, and extending to the central tegmental tract.


CONCLUSIONS
Dopaminergic dysfunction plays a role in the occurrence and severity of midbrain dystonia, and additional lesions to dopaminergic neurons in the perirubral and retrorubral areas result in tremor that responds to levodopa treatment.
Vidailhet
M
M
The French Institute of Health and Medical Research INSERM U289, Paris. marie.vidailhet@sat.ap-hop-paris.fr
Dupel
C
C
Lehéricy
S
S
Remy
P
P
Dormont
D
D
Serdaru
M
M
Jedynak
P
P
Veber
H
H
Samson
Y
Y
Marsault
C
C
Agid
Y
Y
D000293:Adolescent; D000368:Aged; D002531:Cerebellum / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D002561:Cerebrovascular Disorders / Q000473:pathology; D003342:Corpus Striatum / Q000378:metabolism; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D004298:Dopamine / Q000378:metabolism*; D004421:Dystonia / Q000000981:diagnostic imaging / Q000378:metabolism*; D005260:Female; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008636:Mesencephalon / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D008875:Middle Aged; D013238:Stereotaxic Techniques; D013378:Substantia Nigra / Q000378:metabolism; D014055:Tomography, Emission-Computed / Q000379:methods*
D005462:Fluorine Radioisotopes; C043437:fluorodopa F 18; D004295:Dihydroxyphenylalanine; D004298:Dopamine