Mechanism and treatment of dropped head syndrome associated with parkinsonism.
Dropped head syndrome (DHS) associated with parkinsonism is not frequent, but it markedly reduces the activities of daily living and is refractory. To elucidate the mechanism and treatment of DHS associated with parkinsonism, we assessed 28 parkinsonian patients with DHS (2 men and 26 women) by examining their clinical features and cervical-muscle-needle and surface electromyographic (EMG) recordings. We also evaluated the effects of lidocaine, muscle afferent block (MAB; 1% lidocaine mixed with ethanol), and botulinum toxin injected into the bilateral sternocleidomastoid muscles (SCMs), which were considered to be the affected muscles. In some patients, DHS occurred after the initiation or loading of dopamine agonists (less common after pergolide than cabergoline and pramipexole). Improvement was noted after a reduction in the dopamine agonist dose in some patients, and loading of l-dopa in others. Needle EMG revealed no evidence for weakness of the dorsal neck muscles. Surface EMG showed a gradual increase in SCMs activity upon passive head lifting. Lidocaine injection into SCMs markedly improved DHS, but the effect was temporary. The effect of botulinum toxin and MAB was not satisfactory. Whereas DHS could have a heterogeneous etiology, dopamine receptor sensitivity may play a role in its pathogenesis. For the treatment of DHS in parkinsonian patients, an increase in the dosage of l-dopa and a decrease in that of the dopamine agonist should be considered. Lidocaine injection (lidocaine test) could be useful for determining the most affected muscle before using botulinum toxin or MAB. Further studies are needed to examine the outcome of such treatments that include GPi-DBS.
Department of Neurology, Juntendo University, Tokyo, Japan.
Genko
G
Oyama
Akito
A
Hayashi
Yoshikuni
Y
Mizuno
Nobutaka
N
Hattori
D000368:Aged; D000369:Aged, 80 and over; D000779:Anesthetics, Local / Q000627:therapeutic use; D001905:Botulinum Toxins / Q000627:therapeutic use; D002492:Central Nervous System Depressants / Q000627:therapeutic use; D015259:Dopamine Agents / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D004576:Electromyography; D000431:Ethanol / Q000627:therapeutic use; D005260:Female; D019416:Head Movements / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008012:Lidocaine / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000209:etiology* / Q000628:therapy*; D009334:Neck Muscles / Q000187:drug effects / Q000503:physiopathology; D020734:Parkinsonian Disorders / Q000150:complications*; D012720:Severity of Illness Index
D000779:Anesthetics, Local; D002492:Central Nervous System Depressants; D015259:Dopamine Agents; D000431:Ethanol; D008012:Lidocaine; D001905:Botulinum Toxins