The authors assessed tardive dyskinesia and the structure and physiology
of speech apparatus, phonation, and articulation speech abnormalities in 27
chronically ill male psychiatric patients. Tardive dyskinesia was
associated with impairment in phonation, intelligibility, and rate of
speech production. Patients with and without tardive dyskinesia had similar
rates of structural and physiological abnormalities of speech apparatus.
The authors conclude that tardive dyskinesia is associated with substantial
impairment in speech.