Cognitive and brain micro-structural correlates of alexithymia in essential tremor patients.

Essential tremor (ET) is the most common movement disorder which has both motor and non-motor findings such as neuropsychiatic symptoms. Alexithymia is defined as inability to identify and describe emotions experienced by one's self or others. In our study, we aimed to evaluate the neurocognitive and brain micro-structural correlates of alexithymia in ET. 40 ET patients (mean age = 53.05 ± 19.74 years), were included. Fahn-Tolosa-Marin Tremor Rating Scale, Toronto Alexithymia Scale (TAS), Beck Depression Inventory, Beck Anxiety Inventory and detailed neurocognitive evaluation were applied to all patients. The patients were divided into three groups based on their TAS scores: no alexithymia, probable alexithymia, definite alexithymia. Diffusion Tensor Imaging (DTI) was performed in all patients. The mean TAS score was 50.05 ± 10.06. Depressive symptoms and anxiety levels were higher in definite alexithymia (p < 0.001, p < 0.01). Partial correlation controlling for age, gender and educational level between alexithymia scores and each cognitive test showed significant association between similarities (p < 0.001) and phonemic verbal fluency (p = 0.04). Left orbitofrontal cortex average diffusion coefficient (ADC) value (p = 0.05), left anterior cingulate cortex fractional anisotropy (FA) value (p = 0.04), right cuneus FA value (p = 0.04), left amygdala ADC value (p = 0.01) and left insula ADC value (p = 0.02) were differed between groups. TAS and DTImetrics were not found to be independently associated with the level of anxiety (p < 0.001) and depressive symptoms (p < 0.01). As a conclusion, impairments in executive function and complex attention were correlated with higher levels of alexithymia in ET. Many micro-structural alterations were determined to be correlated with alexithymia levels.

Alexithymia is associated with cognitive impairment in patients with Parkinson's disease.

Background and purpose: Cognitive dysfunction (CD) is a common non-motor symptom of Parkinson's disease (PD). Alexithy-mia is a still poorly understood neuropsychiatric feature of PD. Cognitive impairment (especially visuospatial dysfunction and executive dysfunction) and alexithymia share com-mon pathology of neuroanatomical structures. We hypo-thesized that there must be a correlation between CD and alexithymia levels considering this relationship of neuroanatomy. Objective - The aim of this study was to evaluate the association between alexithymia and neurocognitive function in patients with PD. Methods: Thirty-five patients with PD were included in this study. The Toronto Alexithymia Scale-20 (TAS-20), Geriatric Depression Inventory (GDI) and a detailed neuropsychological evaluation were performed. Results: Higher TAS-20 scores were negatively correlated with Wechsler Adult Intelligence Scale (WAIS) similarities test score (r =-0.71, p value 0.02), clock drawing test (CDT) scores (r=-0.72, p=0.02) and verbal fluency (VF) (r=-0.77, p<0.01). Difficulty identifying feelings subscale score was negatively correlated with CDT scores (r=-0.74, p=0.02), VF scores (r=-0.66, p=0.04), visual memory immediate recall (r=-0.74, p=0.01). VF scores were also correlated with difficulty describing feelings (DDF) scores (r=-0.66, p=0.04). There was a reverse relationship bet-ween WAIS similarities and DDF scores (r=-0.70, p=0.02), and externally oriented-thinking (r=-0.77,p<0.01). Executive function Z score was correlated with the mean TAS-20 score (r=-62, p=0.03) and DDF subscale score (r=-0.70, p=0.01). Conclusion: Alexithymia was found to be associated with poorer performance on visuospatial and executive function test results. We also found that alexithymia was significantly correlated with depressive symptoms. Presence of alexithymia should therefore warn the clinicians for co-existing CD.