Correlation between alexithymia and hypersensitivity to visceral stimulation in human

Abstract

Empirical studies indicate that alexithymia exacerbates physical illness. However, direct evidence to explain the mechanism of this exacerbation has not been provided. One hypothesis is that alexithymics amplify unpleasant internal signals. In the present study, we investigated how alexithymia influences sensitivity to visceral stimulation in human. In 45 non-clinical healthy subjects (34 males and 11 females), brain processing of visceral sensation induced by colonic distension was examined using H(2)(15)O positron emission tomography (PET). Subjective feeling evaluated on an ordinate scale and neuroendocrine response to stimuli were also measured. The degree of alexithymia was determined using the 20-item of Toronto alexithymia scale (TAS-20), and the correlation between reaction to stimuli and the scores of TAS-20 and its three subscales [difficulty to identify feelings (DIF), difficulty to describe feelings (DDF) and external oriented thinking (EOT)] was evaluated. Greater activation was observed during colonic distension in the pregenual anterior cingulate cortex, right insula and midbrain in the 10 (out of 45) subjects that were identified as alexithymic by TAS-20 scores larger than 61. TAS-20 scores positively correlated with both activity in the right insula and orbital gyrus and adrenaline levels in the blood in response to stimulation. Subjects with high scores of DIF perceived strong pain, urgency for defecation, stress, anxiety, and slight sleepiness. The present study demonstrates that alexithymia is associated with hypersensitivity to visceral stimulation. This finding supports the somatosensory amplification hypothesized in alexithymics and is important to elucidate the influence of alexithymia on brain-gut function, particularly to understand the pathophysiology of FGIDs (functional gastrointestinal disorders).

Post-Traumatic Stress Disorder, Alexithymia and Somatoform Dissociation in Patients with Fibromyalgia

“…Studies on healthy volunteers have shown a positive relationship between alexithymia and measures of pain sensitivity during experimental pain induction (26,27). A similar association has been described in general medical patients, and whether a relationship between alexithymia and experimental pain sensitivity exists in patients with chronic pain remains unclear (28).…”

Alexithymia in Adolescents with Autism Spectrum Disorder: Its Relationship to Internalising Difficulties, Sensory Modulation and Social Cognition

“…On the one hand, individuals with elevated alexithymia can exhibit hypersensitivity to sensory input, such as lower tolerance of pain and heat, and over responsiveness to visceral stimulation (Kano et al 2007;Katz et al 2009;Nyklicek and Vingerhoets 2000). On the other hand, they also show reduced awareness and registration of internal bodily signals (Ernst et al 2014).…”

“…Bird and Cook (2013) have suggested that emotion recognition and empathy atypicalities seen in individuals with ASD may result from (co-occurring) alexithymia rather than ASD itself. Furthermore, given that alexithymia is associated with higher rates of anxiety and depression (Bankier et al 2001;Berthoz et al 1999;Honkalampi et al 2000) and atypical responses to sensory input (Herbert et al 2011;Kano et al 2007;Katz et al 2009;Lyvers et al 2014;Nyklicek and Vingerhoets 2000) in non-ASD populations, individual differences in alexithymia may also be associated with the increased rates of internalising disorders and sensory sensitivities in ASD. Taylor et al (1999) propose that alexithymia is primarily a disorder of affect regulation, leading to difficulties in modulating the autonomic nervous system, thus resulting in hyper-arousal in response to stress.…”

Suffering at work, emotional repression and musculoskeletal disorders

“…48 Les sujets alexithymiques présentent une augmentation des marqueurs circulants de l'inflammation (Honkalampi, 2011), une réduction plus lente de l'activation neurovégétative à la suite d'un stress (Halpern, 2012) et une hypersensibilité aux stimuli désagréables d'origine externe (Schäfer, 2007) ou interne (Kano, 2007), objectivée par le constat d'une activation plus importante des zones concernées du cortex cérébral.…”