DICHOTIC-LISTENING DURING AUDITORY HALLUCINATIONS IN PATIENTS WITH SCHIZOPHRENIA

Objective: Auditory hallucinations are a serious problem for a large s ubgroup of psychotic patients who do not respond optimally to neurolep tic medication. It has been hypothesized that hearing imaginary voices involves the same physiological processes as those involved in hearin g real voices, but this hypothesis has not been conclusively confirmed . Method: In this study a consonant-vowel version of the Dichotic List ening Test was used to assess the functional integration of the left h emisphere in hallucinating and nonhallucinating psychotic patients. Th e test was administered under three conditions: a nonforced attention condition, a condition in which attention was forced to the left ear, and one in which attention was forced to the right ear. Results: The n onhallucinating patients showed the normal right ear advantage, which indicates a left hemisphere superiority in the processing of linguisti c stimuli. In contrast, the hallucinating patients showed no ear advan tage, Neither group was able to modify its performance when instructed to attend to either the left or the right ear. A subgroup of patients was tested in both hallucinating and nonhallucinating states, but the ear asymmetry was not noticeably different between these states. Conc lusions: The results suggest that auditory hallucinations are associat ed with abnormalities in left hemisphere functioning and that these ab normalities might not be limited to the time of the auditory hallucina tions. It is hypothesized that a relatively enduring left hemisphere a bnormality may leave some patients at risk for auditory hallucinations .