Behavioral measures and event-related potentials reveal different aspects of sentence processing and comprehension in patients with major depression.

BACKGROUND

We used the method of event-related potentials (ERPs) during standard semantic judgment task to explore the functional relationship between the deficit in semantic comprehension in women with depression and the potential dysfunction of brain processes mediating language comprehension.

METHOD

Eleven patients with major depression and 13 healthy participants were required to read congruous and incongruous sentences and to judge if they made sense. Accuracy and reaction times for semantic judgment were analyzed conjointly with the latency and the peak amplitudes of N100, P200, N400 and LPC components which were recorded at the final word of correctly judged sentences.

RESULTS

Patients were less accurate in semantic judgment in comparison to healthy participants. They exhibited slower reaction times and prolonged latency of the N400 and the LPC. A congruity effect was observed in both groups in P200, N400 and LPC interval. The peak amplitude of the ERP components did not differ between patients and healthy participants. In patients lower accuracy was correlated with more prolonged N400 latency and more negative N400 amplitude for congruous sentence endings. Age correlated with prolonged latency and amplitude reduction of the LPC component.

LIMITATIONS

Small number of participants, exclusively female patients.

CONCLUSIONS

Combined analyses of behavior and ERP measures of semantic processes in depression showed that semantic impairments, motor slowness and a delay in the timing of neural processes which mediate language comprehension might be functionally related and may be influenced by the age of the patients.