Behavioral and electrophysiological indices of temporal processing dysfunction in schizophrenia.

Timing deficits in schizophrenia have been noted in several behavioral studies. However, the involvement of mediating factors, such as inattention, has not been ruled out as contributing to these effects. Mismatch negativity (MMN), an electrophysiological measure, may provide a more direct index of stimulus processing ability in individuals with schizophrenia. The current study explored the relationship between behavioral time judgments and a time-based MMN paradigm. Participants were administered two MMN paradigms consisting of an "easy" or "difficult" deviant and an analogous behavioral measure of time processing. Matched against a healthy comparison group, patients exhibited decreased MMN amplitude on the "difficult" deviant interval only. However, on the behavioral paradigm, the patients made significantly more errors across all conditions. These results suggest that behavioral measures of time processing may reflect different processes than those captured by preattentive physiological measures in this population.