The atypical antipsychotic drug olanzapine has been proposed for treatment of dopaminergic psychosis in Parkinson's disease (PD). We report on a 68-year-old patient who developed a severe akinetic-rigid extrapyramidal syndrome, accompanied by additional paranoid symptoms, following olanzapine treatment of optic hallucinosis in PD. Olanzapine may also induce clinically relevant extrapyramidal side effects in PD patients.

Research into the processing of lexical ambiguities has provided a valuable paradigm for investigating the functional architecture of the language processing system in normal and neurologically impaired populations and specifically, how basal ganglia circuits and the neurotransmitter dopamine may act to enhance and/or suppress various meanings relative to the context in which the lexical ambiguity appears. In this review, we develop the hypothesis that an integrated basal ganglia thalamocortical circuit linking the striatum and inferior frontal cortex is involved in the enhancement and suppression of ambiguous word meanings when a lexical ambiguity is presented within a linguistic context. Reference to behavioral, neurophysiological, and neurochemical studies of subcortical function in both healthy populations and people with Parkinson's disease will be used to provide further support for the proposal that the subcortex is integrally involved in ambiguous word processing. (JINS, 2008, 14, 351–364.)