Perception of prosodic and linguistic material in depression
This study compared 27 depressed patients and 27 control participants on the lateralization of prosodic and linguistic comprehension using a dichotic listening task. The comprehension of linguistic material is a left hemisphere process, whereas the comprehension of emotional prosody is a right hemisphere process. Previous studies provide evidence for reduced left anterior (relative to right) and right posterior cortical activation in depression; it was therefore predicted that depressed patients would show different patterns of lateralization for these two processes. This study was the first to examine the lateralization of prosodic and linguistic comprehension using identical stimuli for both tasks in depressed patients. All subjects demonstrated a right ear advantage (left hemisphere) for linguistic processing and a left ear advantage (right hemisphere) for prosodic processing. Depression was not associated with significant differences in the lateralization of linguistic or prosodic comprehension. Some of the results were suggestive of reduced left anterior cortical activation but did not reach statistical significance. Results also suggest that depression and anxiety may have opposing effects on cerebrallateralization.