Effects of central dopaminergic stimulation by apomorphine on speech in Parkinson's disease.
OBJECTIVE
To determine the effect of central dopaminergic stimulation with apomorphine on speech in PD.


BACKGROUND
Most patients with PD have a speech disorder. Of those, 89% have involvement of laryngeal function, and 45% have additional articulatory dysfunction. The effect of dopaminergic medications on these two dimensions of speech impairment in PD has not been selectively studied.


METHODS
In a randomized, double-blind, placebo-controlled crossover design, patients with PD and speech impairment, Hoehn and Yahr stages 2 to 4 "off," and without severe dyskinesias were given placebo or apomorphine injections 0.05 mg/kg subcutaneously during two consecutive outpatient visits. They were pretreated with domperidone for 48 hours and were tested off their parkinsonian medications for 12 hours. Laryngeal function was assessed by maximum sustained vowel phonations and comfortable vowel phonations. Articulatory function was evaluated by speech intelligibility score, speaking rate, and efficiency ratio.


RESULTS
Ten patients, mean age 73.4 years (SD = 6.6), disease duration 8.7 years (SD = 6.3), were tested. The baseline motor score on the Unified Parkinson's Disease Rating Scale (UPDRSm) and all experimental speech variables were equivalent on both placebo and apomorphine days. At a dose of apomorphine that provoked improvement in UPDRSm (p = 0.0078), no index of either laryngeal or articulatory function improved significantly after apomorphine administration.


CONCLUSIONS
Laryngeal and articulatory speech components are not under prominent dopaminergic control in PD. Treatment regimens should focus on nondopaminergic pharmacology and other therapies.
Kompoliti
K
K
Department of Neurological Sciences, Rush-Presbyterian-St. Luke's Medical Center, Rush University, Chicago, IL, USA. kkompoli@rush.edu
Wang
Q E
QE
Goetz
C G
CG
Leurgans
S
S
Raman
R
R
D000368:Aged; D000369:Aged, 80 and over; D000978:Antiparkinson Agents / Q000008:administration & dosage*; D001058:Apomorphine / Q000008:administration & dosage*; D004298:Dopamine / Q000502:physiology*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007830:Larynx / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000188:drug therapy* / Q000503:physiopathology; D013060:Speech / Q000187:drug effects*; D016896:Treatment Outcome
D000978:Antiparkinson Agents; D001058:Apomorphine; D004298:Dopamine