Pharmakologische Zusatzbehandlung in der Aphasietherapie

Short-term prognosis for speech and language in first stroke patients

OBJECTIVE: To evaluate the factors that can influence evolution of communication after a first stroke. METHOD: Thirty-seven adult patients were evaluated for speech and language within 72 hours after a single first-ever ischemic brain injury and later on. Patients who were comatose, with decompensated systemic diseases, or history of chronic alcoholism or illicit drug use were not included. Brain CT and/or 2T-MR exams were solicited for topographic correlation. Size of infarct was classified as large or small according to the TOAST classification. RESULTS: Patients who survived had lesser chances of presenting with aphasia or dysarthria 3 months after the stroke if the infarct size was small (p=0.017). Gender, age, schooling, aphasia subtype, infarct side and topography were non-significant in our sample. Subjects with global aphasia or lone cortical dysarthria had a slower evolution. CONCLUSION: Brain injury size was the most influential factor for neurological outcome at 3 months post-stroke.

Tonic dopaminergic stimulation impairs associative learning in healthy subjects

Endogenous dopamine plays a central role in salience coding during associative learning. Administration of the dopamine precursor levodopa enhances learning in healthy subjects and stroke patients. Because levodopa increases both phasic and tonic dopaminergic neurotransmission, the critical mechanism mediating the enhancement of learning is unresolved. We here probed how selective tonic dopaminergic stimulation affects associative learning. Forty healthy subjects were trained in a novel vocabulary of 45 concrete nouns over the course of 5 consecutive training days in a prospective, randomized, double-blind, placebo-controlled design. Subjects received the tonically stimulating dopamine-receptor agonist pergolide (0.1 mg) vs placebo 120 min before training on each training day. The dopamine agonist significantly impaired novel word learning compared to placebo. This learning decrement persisted up to the last follow-up 4 weeks post-training. Subjects treated with pergolide also showed restricted emotional responses compared to the PLACEBO group. The extent of 'flattened' affect with pergolide was related to the degree of learning inhibition. These findings suggest that tonic occupation of dopamine receptors impairs learning by competition with phasic dopamine signals. Thus, phasic signaling seems to be the critical mechanism by which dopamine enhances associative learning in healthy subjects and stroke patients.