Temperature sensitivity in multiple sclerosis: An overview of its impact on sensory and cognitive symptoms

Abstract

Multiple sclerosis (MS) is an autoimmune neurodegenerative disease characterized by demyelination of the central nervous system (CNS). The exact cause of MS is still unknown; yet its incidence and prevalence rates are growing worldwide, making MS a significant public health challenge. The heterogeneous distribution of demyelination within and between MS patients translates in a complex and varied array of autonomic, motor, sensory and cognitive symptoms. Yet a unique aspect of MS is the highly prevalent (60-80%) temperature sensitivity of its sufferers, where neurological symptoms are temporarily exacerbated by environmental-or exercise-induced increases (or decreases) in body temperature. MS temperature sensitivity is primarily driven by temperature-dependent slowing or blocking of neural conduction within the CNS due to changes in internal (core) temperature; yet changes in skin temperature could also contribute to symptom exacerbation (e.g. during sunlight and warm ambient exposure). The impact of temperature sensitivity, and particularly of increases in core temperature, on autonomic (e.g. thermoregulatory/cardiovascular function) and motor symptoms (e.g. fatigue) is well described. However, less attention has been given to how increases (and decreases) in core and skin temperature affect sensory and cognitive symptoms. Furthermore, it remains uncertain whether changes in skin temperature alone could also trigger worsening of symptoms. Here we review the impact of temperature sensitivity on MS sensory and cognitive function and discuss additional factors (e.g. changes in skin temperature) that potentially contribute to temperature-induced worsening of symptoms in the absence of alteration in core temperature.

Autonomic dysfunctions in multiple sclerosis: Challenges of clinical practice (Review)

“…The mechanisms behind this phenomenon include changes in the axons affected by the demyelination and also in the ion channels due to the changes in the body temperature that result in diminished or blocked transmission through those fibers. Preeminently lesions in the brainstem rather than in the hypothalamus would be involved (3). Cold sensitivity is also causing worsening of symptoms among patients, with a higher proportion of them complaining about it during winter than during cold baths, demyelinating lesions in the hypothalamus being primarily involved (3).…”

“…Preeminently lesions in the brainstem rather than in the hypothalamus would be involved (3). Cold sensitivity is also causing worsening of symptoms among patients, with a higher proportion of them complaining about it during winter than during cold baths, demyelinating lesions in the hypothalamus being primarily involved (3).…”

“…The most common sensory symptoms reported are temperature sensitivity, paraesthesia, and body pain. Motor impairments include fatigue, balance deficits, spasticity, muscle weakness, and dysarthria (3). Multiple studies that evaluated the thermoregulatory dysfunctions in MS are showing little evidence on whether only changes in core temperature are responsible for the symptoms or skin temperature is also involved.…”

Thermoregulation: From basic neuroscience to clinical neurology, part 2

“…Overwhelming new information has been recently published about the immunological background of this disease, and new drugs are being developed, based on this information. Thermoregulatory dysfunction in multiple sclerosis is becoming the new focus of interest [4]. Chapter 42, written by Scott L. Davis, Ollie Jay and Thad E. Wilson, summarizes the present knowledge of thermoregulatory dysfunction in this disease and gives inspiration for further research to better understand the increased temperature sensitivity in multiple sclerosisa major determinant of the quality of life of these patients.…”

Heat risk exacerbation potential for neurology patients during the COVID-19 pandemic and related isolation

“…Heat sensitivity is especially prevalent in those with multiple sclerosis , where 60 to 80% of people report worsening neurological symptoms as body temperature rises. Elevated body temperature typically occurs via a combination of warm environments (passive) and physical activity (active), which may predispose neurology patients to greater negative effects on overall health; excess heat also exacerbates fatigue, cognitive impairment, and balance loss (Christogianni et al 2018 ). Motor neuron diseases , such as amyotrophic lateral sclerosis, are also at increased risk of heat-related illness due to a combination of altered thermoregulatory capacity in the severely disabled, and cognitive deficit (Dupuis et al 2018 ).…”