Alexithymia, depression, and cognition in patients with Parkinson's disease

Basal ganglia are connected to dorsal prefrontal and orbitofrontal structures, which have an important role in emotional experience. Alexithymia is defined as the inability to recognize and verbalize emotions. There is little known about alexithymia and cognitive dysfunction and its relationship with depression. In this study, we examined the relation of alexithymia with cognition and depression in non-demented patients with Parkinson's disease (PD).

Fort-two consecutive non-demented patients PD and 40 healthy controls were enrolled in the study. The Turkish version of the Montreal Cognitive Assessment scale (MOCA-TR), 20-item Toronto Alexithymia Scale (TAS-20) (F1, F2, F3 subgroups), and Beck Depression Inventory (BDI-I) were used to evaluate cognitive functions, alexithymia, and depression, respectively, in both groups.

The total TAS-20 score was 55.71 ± 19 in the PD group and 46.33 ± 8.21 in the control group. There was a statistically significant difference in the total TAS-20 scores between the groups (p < 0.001). In subgroups of alexithymia, all mean scores of F1, F2, and F3 were higher in the PD group (p = 0.019, p < 0.001, and p = 0.005, respectively). In the MOCA-TR test, the mean scores in visuospatial and delayed recall of patients with PD were statistically lower than in the control group (p = 0.044 and p = 0.04, respectively). The MOCA-TR and BDI total scores were significantly correlated with TAS-20 total scores. In subgroup analysis, we only found an association between the visuospatial domain of MOCA-TR and the F3 subgroup of TAS-20 (r = - 0.22, p = 0.03). There was no relation between alexithymia and disease duration or total levodopa dose (p < 0.05).

Alexithymia is not a rare symptom in PD. It should be accepted as an independent non-motor symptom, and patients should be interrogated accordingly.