Objectives: Previous studies have linked alexithymia to an inability to process emotions appropriately. Older persons show changes in emotion processing and have higher alexithymia scores. Because the anterior cingulate cortex (ACC) is one of the regions showing earlier decline in late-life, and alexithymia seems to be related to a dysfunction in right hemisphere regions including the ACC subserving affective processes, the present study sought to test the hypothesis that reduced ACC volume accounts for the association between older age and alexithymia.
Design: Correlation analyses between functionally distinct ACC subregions, age and alexithymia features.
Setting: University of Iowa.
Participants: Twenty-four healthy volunteers aged between 24 and 79 years.
Measurements: Psychiatric and neuropsychological assessment and assessment of alexithymia using the 20-item Toronto Alexithymia Scale. High-resolution magnetic resonance imaging, and in-house developed methods for ACC parcellation.
Results: Older age directly correlated with higher overall alexithymia and reduced bilateral rostral and right dorsal ACC gray matter volume. Furthermore, higher alexithymia scores correlated with reduced right rostral ACC volume. This correlation seems to be influenced primarily by Factor 3 of the alexithymia scale measuring diversion of attention to external details in place of internal feelings.
Conclusions: These results suggest that alexithymia in older age may be a result of structural changes in the right rostral ACC.