An Initial Study of Alexithymia and Its Relationship With Cognitive Abilities Among Mild Cognitive Impairment, Mild Alzheimer's Disease, and Healthy Volunteers

The present study examined the degree to which alexithymia is greater in mild Alzheimer's disease (AD) and mild cognitive impairment (MCI) relative to healthy volunteers (healthy comparison [HC]), and investigated relationships between alexithymia and cognition. Eighty-five participants (MCI = 30, AD = 21, HC = 34) underwent a comprehensive neuropsychological examination and completed the 20-item Toronto Alexithymia Scale (TAS-20). Relative to HC, MCI and AD reported greater alexithymia total scores and higher scores on the TAS factor difficulty in identifying feelings (DIF). The remaining two factors, difficulty in describing feelings (DDF) and externally oriented thinking showed no significant group differences. In MCI, TAS-20 and DIF were negatively correlated with working and long-term verbal memory. In AD, TAS-20 was negatively correlated with general cognition, attention, memory, and visual spatial constructive and executive abilities. Also in AD, DIF was negatively correlated with general cognition, memory, and executive abilities. The correlation between DIF and long-term verbal memory in both MCI and AD suggests a potential common mechanism for alexithymia in these neurocognitive disorders. Declines in verbal memory may hinder a patient's ability to recall an association between a given sensation and the episodic experience of that sensation, thus leading to difficulty identifying feelings, as measured by the DIF factor of the TAS-20.