Alexithymia in patients with Parkinson's disease treated with DBS of the subthalamic nucleus: a case-control study

Possible Implications of Managing Alexithymia on Quality of Life in Parkinson's Disease: A Systematic Review

Alexithymia, characterized by difficulty in recognizing and verbalizing emotions, is reported to be more prevalent in subjects with Parkinson's disease (PD) than in the general population. Although it is one of the nonmotor symptoms of PD, alexithymia is often overlooked in clinical practice. The aim of this systematic review is to investigate the prevalence of alexithymia in PD, assess its impact on quality of life, and explore the rehabilitation approaches for alexithymia. Research articles, selected from PubMed, Scopus, and Web of Science, were limited to those published in English from 2013 to 2023. The search terms combined were "Alexithymia," "Parkinson's disease,", and "Quality of life." Current literature review indicates that alexithymia is commonly assessed using the Toronto Alexithymia Scale (TAS-20), and it is associated with deficits in visuospatial and executive functions. Presently, rehabilitation interventions for alexithymia are scarce, and their effectiveness remains controversial. Future research should focus on developing comprehensive assessments and rehabilitation strategies for emotional processing, considering its significant impact on the quality of life of both patients and caregivers.

Neurocognitive Impairment and Social Cognition in Parkinson's Disease Patients

In addition to motor symptoms, neurocognitive impairment (NCI) affects patients with prodromal Parkinson's disease (PD). NCI in PD ranges from subjective cognitive complaints to dementia. The purpose of this review is to present the available evidence of NCI in PD and highlight the heterogeneity of NCI phenotypes as well as the range of factors that contribute to NCI onset and progression. A review of publications related to NCI in PD up to March 2023 was performed using PubMed/Medline. There is an interconnection between the neurocognitive and motor symptoms of the disease, suggesting a common underlying pathophysiology as well as an interconnection between NCI and non-motor symptoms, such as mood disorders, which may contribute to confounding NCI. Motor and non-motor symptom evaluation could be used prognostically for NCI onset and progression in combination with imaging, laboratory, and genetic data. Additionally, the implications of NCI on the social cognition of afflicted patients warrant its prompt management. The etiology of NCI onset and its progression in PD is multifactorial and its effects are equally grave as the motor effects. This review highlights the importance of the prompt identification of subjective cognitive complaints in PD patients and NCI management.

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

BACKGROUND

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).

MATERIALS AND METHODS

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.

RESULTS

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).

CONCLUSION

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

Impulsivity in Parkinson's disease patients treated with subthalamic nucleus deep brain stimulation-An exploratory study

BACKGROUND

Deep brain stimulation of the subthalamic nucleus (STN-DBS) is a recognized treatment in Parkinson's disease (PD). Knowledge is still limited regarding the possible impact of STN-DBS on personality traits and the personality characteristics of PD patients who undergo surgery.

METHODS

To assess personality traits in relation to STN-DBS we did an ancillary protocol as part of a prospective randomized study that compared two surgical strategies. Patients were assessed with the Temperament and Character Inventory (TCI), the Urgency, Premeditation, Perseverance and Sensation Seeking impulse behavior scale, the Eysenck Personality Questionnaire (EPQ) and the Toronto Alexithymia Scale preoperatively and after one year of STN-DBS. EPQ and TCI baseline scores were compared with mean scores of healthy reference populations.

RESULTS

After 12-months of STN-DBS, there was a significant decline in Persistence compared to baseline. Preoperatively, the STN-DBS patients had significantly lower Persistence and Self-Transcendence scores, and significantly higher scores on Novelty-Seeking, Self-Directedness, Cooperativeness and on Social Conformity than referenced populations. No difference was found in Neuroticism or Harm-Avoidance scores. The baseline prevalence of alexithymia was low and at 1-year follow-up there was no significant change in alexithymia scores.

CONCLUSIONS

We found a higher baseline level of impulsivity in PD patients who underwent STN-DBS. After one year of STN-DBS, our results indicated that the treatment may affect the patients' personality by increasing certain aspects of impulsivity. There was no effect on alexithymia. The preoperative personality profile of PD patients might influence the outcome of STN-DBS.

Determinants and impact of alexithymia on quality of life in Parkinson's disease

INTRODUCTION

Alexithymia is a neuropsychiatric symptom conceptualized as difficulty identifying and describing feelings. Although associated with other non-motor symptoms, mainly neuropsychiatric, alexithymia may present as an isolated symptom in persons with Parkinson's Disease (PwP). The objective of the study is to identify determinants of alexithymia and its association with quality of life (QoL) in Parkinson's disease.

METHODS

Subjects with Parkinson's disease were recruited. The following instruments were applied: Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Non-Motor Symptoms Scale (NMSS), Montreal Cognitive Assessment (MoCA), Toronto alexithymia scale (TAS-20) and Parkinson's Disease Questionnaire (PDQ-8). Matched healthy controls were screened using TAS-20. Clinical and demographical variables were compared between alexithymic and non-alexithymic. Regression models were used to find determinants of alexithymia. Impact of alexithymia on QoL was estimated with a linear regression model.

RESULTS

98 patients were included. 56.1% PwP and 28.8% controls were alexithymic (p<0.001). Education level (OR 0.86) and NMSS urinary score (OR 1.09) determined alexithymia as well as TAS-20 score. Alexithymia was an independent determinant of QoL.

CONCLUSIONS

Alexithymia is a prevalent independent non-motor symptom in PwP with impact on QoL. Low education level and urinary symptoms are important determinants of alexithymia.

Beneficial effects of bilateral subthalamic stimulation on alexithymia in Parkinson's disease

BACKGROUND AND PURPOSE

Subthalamic nucleus (STN) deep brain stimulation (DBS) improves quality of life (QoL) and motor and non-motor symptoms in advanced Parkinson's disease (PD). However, its effect on alexithymia and its relationship to other neuropsychiatric symptoms and QoL in PD is unclear.

METHODS

In this prospective, observational study of 39 patients with PD undergoing STN-DBS, we examined the Parkinson's Disease Questionnaire-8 (PDQ-8), 20-item Toronto Alexithymia Scale (TAS-20), Hospital Anxiety and Depression Scale (HADS), Self-Report Manic Inventory (SRMI), Apathy Evaluation Scale (AES), Unified Parkinson's Disease Rating Scale (UPDRS) activities of daily living, UPDRS motor examination and UPDRS complications (UPDRS-II/-III/-IV) and levodopa-equivalent daily dose (LEDD) pre-operatively and at 5-month follow-up. Outcome changes were tested with Wilcoxon signed-rank or paired t-test when parametric tests were applicable and corrected for multiple comparisons. The relationship between outcome changes was explored with bivariate correlations. Additionally, partial correlations between PDQ-8 and TAS-20 were computed controlling for HADS, SRMI and AES change scores. Predictor analyses for PDQ-8 improvement were calculated for all baseline parameters.

RESULTS

The baseline prevalence of alexithymia was 17.9%. We observed significant beneficial effects of STN-DBS on PDQ-8, TAS-20, HADS, UPDRS-II, -III and -IV scores and significant LEDD reduction. The correlation between TAS-20 and PDQ-8 improvements remained significant after controlling for all other aforementioned outcomes. Predictor analyses for PDQ-8 improvement were significant for PDQ-8 and TAS-20.

CONCLUSIONS

This is the first report of beneficial effects of STN-DBS on alexithymia. Alexithymia was significantly associated with QoL outcome independent of anxiety, depression, mania and apathy. Our study highlights the importance of alexithymia for holistic assessments of DBS outcomes.

Cognitive, Emotional, and Auto-Activation Dimensions of Apathy in Parkinson's Disease

Apathy is one of the most frequent non-motor manifestations in Parkinson's disease (PD) that can lead to a whole range of deleterious outcomes. In 2006, Levy and Dubois proposed a model that distinguishes three different apathy aetiologies in PD divided into three subtypes of disrupted processing: “emotional-affective,” “cognitive,” and “auto-activation.” These three dimensions associated with dopamine depletion present in the pathology would lead to the emergence of apathy in PD. The aim of this mini-review was to describe and discuss studies that have explore links between apathy and the three subtypes of disrupted processing proposed by Levy and Dubois (2006) and as well as the links between these dimensions and dopamine depletion in Parkinson's disease. The lack of consensus regarding the emotional-affective correlates of apathy and the lack of evidence supporting the hypothesis of the auto-activation deficit, do not clearly confirm the validity of Levy and Dubois's model. Furthermore, the suggested association between dopaminergic depletion and apathy must also be clarified.

Emotion processing in Parkinson's disease: a three-level study on recognition, representation, and regulation

BACKGROUND

Parkinson's disease (PD) is characterised by well-known motor symptoms, whereas the presence of cognitive non-motor symptoms, such as emotional disturbances, is still underestimated. One of the major problems in studying emotion deficits in PD is an atomising approach that does not take into account different levels of emotion elaboration. Our study addressed the question of whether people with PD exhibit difficulties in one or more specific dimensions of emotion processing, investigating three different levels of analyses, that is, recognition, representation, and regulation.

METHODOLOGY

Thirty-two consecutive medicated patients with PD and 25 healthy controls were enrolled in the study. Participants performed a three-level analysis assessment of emotional processing using quantitative standardised emotional tasks: the Ekman 60-Faces for emotion recognition, the full 36-item version of the Reading the Mind in the Eyes (RME) for emotion representation, and the 20-item Toronto Alexithymia Scale (TAS-20) for emotion regulation.

PRINCIPAL FINDINGS

Regarding emotion recognition, patients obtained significantly worse scores than controls in the total score of Ekman 60-Faces but not in any other basic emotions. For emotion representation, patients obtained significantly worse scores than controls in the RME experimental score but no in the RME gender control task. Finally, on emotion regulation, PD and controls did not perform differently at TAS-20 and no specific differences were found on TAS-20 subscales. The PD impairments on emotion recognition and representation do not correlate with dopamine therapy, disease severity, or with the duration of illness. These results are independent from other cognitive processes, such as global cognitive status and executive function, or from psychiatric status, such as depression, anxiety or apathy.

CONCLUSIONS

These results may contribute to better understanding of the emotional problems that are often seen in patients with PD and the measures used to test these problems, in particular on the use of different versions of the RME task.

Emotion processing in Parkinson's disease: a three-level study on recognition, representation, and regulation

BACKGROUND

Parkinson's disease (PD) is characterised by well-known motor symptoms, whereas the presence of cognitive non-motor symptoms, such as emotional disturbances, is still underestimated. One of the major problems in studying emotion deficits in PD is an atomising approach that does not take into account different levels of emotion elaboration. Our study addressed the question of whether people with PD exhibit difficulties in one or more specific dimensions of emotion processing, investigating three different levels of analyses, that is, recognition, representation, and regulation.

METHODOLOGY

Thirty-two consecutive medicated patients with PD and 25 healthy controls were enrolled in the study. Participants performed a three-level analysis assessment of emotional processing using quantitative standardised emotional tasks: the Ekman 60-Faces for emotion recognition, the full 36-item version of the Reading the Mind in the Eyes (RME) for emotion representation, and the 20-item Toronto Alexithymia Scale (TAS-20) for emotion regulation.

PRINCIPAL FINDINGS

Regarding emotion recognition, patients obtained significantly worse scores than controls in the total score of Ekman 60-Faces but not in any other basic emotions. For emotion representation, patients obtained significantly worse scores than controls in the RME experimental score but no in the RME gender control task. Finally, on emotion regulation, PD and controls did not perform differently at TAS-20 and no specific differences were found on TAS-20 subscales. The PD impairments on emotion recognition and representation do not correlate with dopamine therapy, disease severity, or with the duration of illness. These results are independent from other cognitive processes, such as global cognitive status and executive function, or from psychiatric status, such as depression, anxiety or apathy.

CONCLUSIONS

These results may contribute to better understanding of the emotional problems that are often seen in patients with PD and the measures used to test these problems, in particular on the use of different versions of the RME task.