Sensory sensitivity assessed using transcutaneous electrical nerve stimulation, anhedonia and quality of life in patients with affective disorders

Sensory sensitivity and intolerance may represent a distinct, empirically defined psychiatric phenotype characterized by distressing sensory symptoms and functional impairment due to atypical sensory processing. The aim of this study, in contrast to prior studies relying primarily on subjective self-report measures, was to objectively assess sensory processing using transcutaneous electrical nerve stimulation (TENS) in individuals with affective and anxiety disorders. TENS was applied with the following parameters: 100 Hz frequency, 100 µs pulse duration, and a biphasic waveform to assess individual detection thresholds. Electrode placement corresponded to the T1 dermatome on the forearm of the dominant hand. Anhedonia was assessed with the Dimensional Anhedonia Rating Scale (DARS) and quality of life with the WHOQOL-BREF. Questionnaire-based measures were included to capture affective and hedonic aspects of functioning that are clinically relevant to the interpretation of sensory processing. In adjusted analyses, the clinical group showed numerically higher detection thresholds than the control group (adjusted difference = 0.84 mA, 95% CI − 0.98 to 2.66); however, the difference was not statistically significant ( p =.367). Group membership was significantly associated with stimulus valence, with participants in the clinical group showing higher odds of reporting a more positive valence category (OR = 3.26, 95% CI 1.10–10.01). Detection thresholds were numerically higher in the clinical group than in the control group, but the adjusted between-group difference was not statistically significant. Group membership was significantly associated with stimulus valence. These findings suggest possible differences in the hedonic appraisal of electrical stimulation among individuals with affective and anxiety disorders, whereas differences in detection thresholds were not statistically significant. They should be interpreted cautiously and require confirmation in further studies. Not applicable.