Changes induced by levodopa and subthalamic nucleus stimulation on parkinsonian speech.
Levodopa (L-dopa) and subthalamic nucleus (STN) stimulation treatments have been associated with both improvement and exacerbation of dysarthria in Parkinson's disease (PD). We report four cases illustrating variant responses of dysarthria to dopaminergic and STN stimulation therapies. Patients' motor disability and dysarthria were perceptually rated by the Unified Parkinson's Disease Rating Scale (UPDRS) in four conditions according to medication and STN stimulation. Dedicated software packages allowed acquisition and analysis of acoustic recordings. Case 1, who had a severe off period aphonia, experienced improvement of speech induced by both levodopa and STN stimulation. In Case 2, both treatments worsened speech due to the appearance of dyskinesias. Case 3 had a dysarthria exacerbation induced by STN stimulation with parameters above optimal levels, interpreted as current diffusion from the STN to corticobulbar fibers. In Case 4, dysarthria exacerbation occurred with stimulation at an electrode contact located caudally to the target, also arguing for current diffusion as a potential mechanism of speech worsening. The presented cases demonstrated variant effects in relation to L-dopa and STN stimulation on speech. It seems that motor speech subcomponents can be improved like other limb motor aspect, but that complex coordination of all speech anatomical substrates is not responsive to STN stimulation. These hypotheses may be helpful for better understanding and management of STN stimulation effects on motor speech and skeleton-motor subsystems.
Pinto
Serge
S
Neurosciences Précliniques, INSERM Unité 318, Grenoble, France. s.pinto@ion.ucl.ac.uk
Gentil
Michèle
M
Krack
Paul
P
Sauleau
Paul
P
Fraix
Valérie
V
Benabid
Alim-Louis
AL
Pollak
Pierre
P
D000328:Adult; D004401:Dysarthria / Q000209:etiology*; D020820:Dyskinesias / Q000209:etiology; D004599:Electric Stimulation Therapy / Q000009:adverse effects*; D007839:Functional Laterality; D006801:Humans; D007980:Levodopa / Q000009:adverse effects*; D008875:Middle Aged; D020734:Parkinsonian Disorders / Q000503:physiopathology* / Q000628:therapy*; D012720:Severity of Illness Index; D020531:Subthalamic Nucleus / Q000503:physiopathology* / Q000528:radiation effects
D007980:Levodopa