Alexithymic features in stroke: effects of laterality and gender

Stroke patients suffer from a high rate of behavioral disorders, and the laterality of the lesion may affect the expression of emotional disturbances. This study tested the hypothesis that stroke patients with a lesion in the right hemisphere are at high risk of developing alexithymic features.

Forty-eight patients were interviewed with the Structured Clinical Interview for DSM-IV (patient edition), the Mini-Mental State Examination, the State-Trait Anxiety Inventory (state form), the Beck Depression Inventory, and the Toronto Alexithymia Scale (20-item version). Alexithymic differences between stroke patients with a lesion in the right hemisphere and those with a lesion in the left hemisphere were computed by analysis of covariance, using scores on the Mini-Mental State Examination, Beck Depression Inventory (psychic subscore), and State-Trait Anxiety Inventory as covariates and the score on the Toronto Alexithymia Scale as the dependent variable. A multivariate analysis of covariance and a series of follow-up analyses of covariance with the same covariates were used to discriminate differences in subscores on the Toronto Alexithymia Scale. An exploratory analysis of covariance was also performed to determine the effect of gender on alexithymic features in both groups of stroke patients.

The 21 stroke patients with a lesion in the right hemisphere were more alexithymic than the 27 patients with a lesion in the left hemisphere. This evidence was strengthened by the categorical analysis: 48% of the patients with a right-hemisphere lesion had alexithymia, compared with 22% of patients with a left-hemisphere lesion. Univariate analyses of covariance showed significant differences between the two groups in difficulty identifying feelings and difficulty describing feelings, but not in externally oriented thinking. The last exploratory analysis of covariance suggested that gender may influence alexithymic features.

This study provides direct evidence that alexithymia, and more specifically difficulty identifying feelings and difficulty describing feelings, is more common in stroke patients with a right-hemisphere lesion than in those with a left-hemisphere lesion. It also provides preliminary evidence that gender may affect alexithymic expression.