Autonomic reactivity to stress in multiple sclerosis: A meta-analytic review.

BACKGROUND: Multiple sclerosis (MS) is a chronic neuroinflammatory and neurodegenerative disease of the central nervous system, often accompanied by anxiety and depression exacerbating physical symptoms and reducing quality of life. OBJECTIVES: Given the central role of the autonomic nervous system in emotional reactivity and regulation, this meta-analytic review examined whether people with MS (PwMS) show altered autonomic responses to emotional or stress-related stimuli compared to controls. METHODS: Fourteen studies were included exploring autonomic signals, such as heart rate (HR) variability (HRV), blood pressure, electrodermal activity, and pupil response, during emotional or psychological stress. Quantitative analyses focused on HR, HRV and blood pressure. RESULTS: Between-group analysis (PwMS vs. controls, k = 6) revealed a large reduction in stress-induced autonomic responses in PwMS (d = -1.21), suggesting a blunted physiological response. Qualitative analysis from other autonomic indices confirmed this alteration. Within-group analysis in PwMS showed a moderate increase in autonomic responsiveness (d = 0.71, p = .079), though non-significant, suggesting residual but reduced reactivity. CONCLUSIONS: Overall, these results reveal attenuated autonomic responses to psychological stress in MS, possibly linked to central lesions affecting stress-regulation networks, and support autonomic reactivity as a potential physiological marker of emotional and functional impairment in MS.