Deciphering the neural underpinnings of alexithymia in multiple sclerosis

Alexithymia in multiple sclerosis: past, present and future

Alexithymia denotes the "absence" of "words" for "emotion" and has its roots in the Greek words "a," "lexis," and "thymos." It is sometimes referred to as "emotional blindness," "blunted feeling," or "disrupted emotional awareness." The term "alexithymia" first appeared in the 1970s in the works of Sifneos, Nemiah, and colleagues. It entails difficulties in identifying and expressing emotions and an externally oriented thinking style. It is not a psychiatric disorder but rather a multidimensional personality trait or construct, appearing to be normally distributed in the general population, with high levels of alexithymia in approximately 10% of individuals. Evidence suggests that alexithymia serves as a prognostic risk factor for health problems, a transdiagnostic risk factor for emotion-based psychopathologies, and a predictor of poor psychiatric treatment outcomes. It is frequently observed in neurological diseases. Nevertheless, its mechanisms, assessment, and management remain overlooked. In multiple sclerosis (MS), an autoimmune disease of the central nervous system, alexithymia seems to occur in up to 53% of patients. However, it remains understudied despite recent growing interest. In this mini review, we briefly reassess the prevalence, as well as the clinical, sociodemographic and neuropsychological correlates of alexithymia in MS (e.g., anxiety, depression, fatigue, socio-emotional outcomes). This is followed by an analysis of neurobiological underpinnings of alexithymia derived from neurophysiological and neuroimaging studies in this clinical population. Finally, we provide perspectives to guide future research exploring and managing alexithymia in MS.

The percentage and clinical correlates of alexithymia in stable patients with schizophrenia

Alexithymia is a common, but less-recognized affective deficit in patients with schizophrenia. To date, no definitive conclusions have been drawn about the relationship between alexithymia and the clinical symptoms or their clinical correlates, particularly in stable patients with schizophrenia. The purpose of this study was to investigate the link between alexithymia and psychopathological symptoms, as well as any associated correlates, in stable patients with schizophrenia. A total of 435 Chinese patients with schizophrenia were recruited. The Positive and Negative Symptoms Scale (PANSS) was used to evaluate each patient's psychopathological symptoms. The Toronto Alexithymia Scale (TAS-20) was used to measure alexithymia. The percentage of alexithymia was 35.2% in stable patients with schizophrenia. Compared to non-alexithymia patients, patients with alexithymia had higher PANSS total scores, negative subscores, depressive subscores, and cognitive subscores (all p < 0.05). Multivariate regression analysis revealed that the following variables were positively associated with TAS-20 total scores: PANSS negative subscores (β = 0.274, t = 3.198, p = 0.001) and PANSS depressive subscores (β = 0.366, t = 2.500, p = 0.013). Education years (β = - 0.453, t = - 2.824, p = 0.005) was negatively associated with TAS-20 total scores. Our results suggest that the percentage of alexithymia was relatively higher in stable patients with schizophrenia. Education levels, negative symptoms, and depressive symptoms were independently associated with alexithymia in this specific population.

Corpus callosum damage to account for cognitive, affective, and social-cognitive dysfunctions in multiple sclerosis: A model of callosal disconnection syndrome?

The corpus callosum (CC) is the major commissure interconnecting the two hemispheres and is particularly affected in multiple sclerosis (MS). In the present review, we aimed to investigate the role played by callosal damages in the pathogenesis of MS-related dysfunctions and examine whether a model of callosal disconnection syndrome is a valid model for MS. For this purpose, we will first review structural and functional evidence of callosal pathology in MS. Second, we will account for the potential role of CC abnormalities in MS-related dysfunctions. Finally, we will report data concurring with a "multiple disconnection hypothesis" that has been proposed to explain those dysfunctions, and we will examine evidence pointing toward MS as a "callosal disconnection syndrome." We will end by discussing the contribution of this interpretation to the understanding of MS and MS-related deficits.

Plasma circulating micro-RNAs associated with alexithymia reflect a high overlap on neuropsychiatric outcomes

BACKGROUND

Alexithymia ("no word for feelings") is a personality feature that is common in patients with psychiatric disorders. However, little is known about biological causes and mechanism behind. Research so far focusses on genetic risk variants primary associated with depression, but analyses on epigenetic mechanisms are still missing.

METHODS

In a sample of n = 813 subjects from the "Study of Health in Pomerania" we analyzed the association between alexithymia and plasma circulating micro RNAs (miRNA). Significant miRNAs were compared to associations regarding depression and pathway analyses were performed.

RESULTS

Two miRNAs were significantly associated with at least one of the alexithymia scores (hsa-miR-324-3p, hsa-miR-33a-5p) and three miRNAs additionally revealed a strong association pattern to alexithymia (hsa-miR-106b-5p, hsa-miR-484, hsa-miR-25-3p). None of these miRNAs was significantly associated with depressive symptoms in our sample. Literature research showed that all of the miRNAs have been found in association with several neuropsychiatric phenotypes.

LIMITATIONS

Main limitations are the lack of a replication sample as well as the limited number of miRNAs analyzed.

CONCLUSIONS

This is the first analysis investigating the association between miRNAs and alexithymia. Results indicate that miRNAs are not specific for one psychiatric disorder but may influence biological mechanisms that are involved in various psychiatric conditions which might be relevant for future treatment options and improve the biological understanding of psychiatric conditions.

Prevalence of Alexithymia in Patients with Medically Unexplained Physical Symptoms: A Cross-sectional Study in Egypt

BACKGROUND

There is a high incidence of alexithymia in people who report medically unexplained symptoms. There have been limited studies on the prevalence of alexithymia in patients with medically unexplained physical symptoms (MUPS) in various ethnic and cultural backgrounds.

OBJECTIVE

This study aimed to estimate the prevalence of alexithymia in patients with MUPS and examine their socio-demographic data.

METHODS

In this cross-sectional study, 196 patients with MUPS were recruited from tertiary care internal medicine and neuropsychiatry clinics during the first quarter of 2019. Patients completed a structured interview; socio-demographic and medical history data were collected. Somatic symptom severity was assessed using the Arabic version of the Patient Health Questionnaire (PHQ-15). Alexithymia was assessed using the Arabic version of the Toronto Alexithymia Scale.

RESULTS

General fatigue was the most common complaint observed, followed by headache and dyspepsia. In addition, 73.5% of patients had a high Patient Health Questionnaire score, 17.9% had somatic symptoms of medium severity, while 8% and 0.5% had low and marginal somatic symptoms, respectively. Alexithymia was presented in 49.5%, 22.9% had no alexithymia, and 27.6% had borderline/intermediate alexithymia.A weak positive correlation (r<0.4) was found between somatic symptom severity and alexithymic psychopathology (r=0.277;p<0.05). Only the 'difficulty identifying feelings' dimension of alexithymic psychopathology was positively correlated with the severity of somatic symptoms (r=0.271;p<0.05).

CONCLUSION

Alexithymia is associated with the development of MUPS.

Relation of Decreased Functional Connectivity Between Left Thalamus and Left Inferior Frontal Gyrus to Emotion Changes Following Acute Sleep Deprivation

Objective: The thalamus is a key node for sleep-wake pathway gate switching during acute sleep deprivation (ASD), and studies have shown that it plays a certain role in emotion changes. However, there are no studies on the association between the thalamus and emotion changes in ASD. In this study, we used resting-state functional magnetic resonance imaging (R-fMRI) to explore whether changes in the functional connections between the thalamus and other brain regions are related to emotion changes and further explored the function of the thalamus under total ASD conditions. Method: Thirty healthy, right-handed adult men underwent emotional assessment according to the Profile of Mood States Scale and R-fMRI scans before and after ASD. The correlations between changes in functional connectivity between the thalamus and other brain regions and emotion changes were then studied. Results: Positive emotions and psychomotor performance were reduced, and negative emotions were increased following ASD. The functional connections between the left thalamus and left middle temporal gyrus, left inferior frontal gyrus, right thalamus, right inferior temporal gyrus, left middle temporal pole gyrus, right calcarine, left cuneus, left rectus and left medial superior frontal gyrus were significantly altered. Decreased functional connectivity between left thalamus and left inferior frontal gyrus related to emotion changes following ASD. Conclusion: This study finds that functional changes in the thalamus are associated with emotion changes during ASD, suggesting that the left thalamus probably plays an essential role in emotion changes under ASD conditions.

Neurocognitive impairment and social cognition in multiple sclerosis

PURPOSE/AIM OF THE STUDY

The impairment of neurocognitive functions occurs in all subtypes of multiple sclerosis, even from the earliest stages of the disease. Commonly reported manifestations of cognitive impairment include deficits in attention, conceptual reasoning, processing efficiency, information processing speed, memory (episodic and working), verbal fluency (language), and executive functions. Multiple sclerosis patients also suffer from social cognition impairment, which affects their social functioning. The objective of the current paper is to assess the effect of neurocognitive impairment and its potential correlation with social cognition performance and impairment in multiple sclerosis patients.

MATERIALS AND METHODS

An overview of the available-to-date literature on neurocognitive impairment and social cognition performance in multiple sclerosis patients by disease subtype was performed.

RESULTS

It is not clear if social cognition impairment occurs independently or secondarily to neurocognitive impairment. There are associations of variable strengths between neurocognitive and social cognition deficits and their neural basis is increasingly investigated.

CONCLUSIONS

The prompt detection of neurocognitive predictors of social cognition impairment that may be applicable to all multiple sclerosis subtypes and intervention are crucial to prevent further neural and social cognition decline in multiple sclerosis patients.