Alexithymia in Parkinson's Disease: A Meta-analysis

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor and non-motor manifestations, including alexithymia. This condition is defined by difficulty in recognizing, articulating, and expressing one's emotional states. In this study, we conducted a systematic review and meta-analysis to compare the prevalence of alexithymia in PD patients and a healthy population, and to identify associated demographic and clinical factors. We identified 16 observational studies through Pubmed, EMBASE, PsycINFO, and SCOPUS, selecting articles published since 2002. Data were analyzed using a random-effects model. We conducted additional prevalence meta-analyses and correlation meta-analyses. We found that PD patients exhibit higher levels of alexithymia compared to the general population (combined effect size 0.65 [95% CI = 0.49-0.81; P <0.05]), and moderate but significant heterogeneity (I² = 52.42%, Q = 29.42, P <0.05), partially explained by regional differences, levodopa equivalent dosage (positive regression coefficient of 0.0006 [95% CI = 0.0001; 0.0011, P <0.05]); and cognitive scores (negative regression coefficient of -0.14 [95% CI = -0.24; -0.04, P<0.05]), after adjusting for covariates. The additional meta-analysis reported higher prevalence of alexithymia in PD and a pooled correlation coefficient of 0.496 (95% CI = 0.40-0.59, P <0.05) when we analyzed alexithymia and depression scores. To our knowledge, there are no previous meta-analysis applied to alexithymia in PD patients. Even though we could not determine whether alexithymia is a primary characteristic of PD, we found an association of higher levels of alexithymia with depression and higher levodopa equivalent daily dose. Furthermore, there are not enough studies to draw clear conclusions about the influence of cognitive status.