Sensory symptoms of multiple sclerosis: a hidden reservoir of morbidity

Objective: To assess the frequency and quality of sensory symptoms in a population of patients with Multiple Sclerosis (MS) and compare them with controls. Design: Survey to target population and control group evaluating demographic data, data on disease course, presence of various symptoms of MS. Setting: Neurological practices affiliated with a tertiary community hospital. Participants: 224 patients with MS, 93 controls of similar age and sex. Results: Sensory symptoms were more common in MS patients than in controls, and differed in severity and quality. Fifty per cent described brief (seconds to hours) episodes of neurological dysfunction, significantly more often than in controls (P=0.001). Pain was present at some time in similar percentages in patients and controls, but active pain problems were present more often in MS patients (P=0.001). The qualitative description of pain in MS patients was more often neuropathic, with burning, itching, electric and formicatory pain, as opposed to throbbing, sharp or muscular pain. Pain was localized to arms, legs, trunk, hands, feet and face more often in the MS group. Lhermitte's phenomenon was present in two-thirds of patients at some time in their disease course. Twenty per cent of the patients identified themselves as having respiratory problems (Controls 7.5%, P=0.005). Fatigue limited activity in 78% of patients, but only in 17% of controls (P=0.001). Dizziness, memory dysfunction, and restless legs symptoms were all more frequent in patients. The self-rated `worst' symptoms of MS was pain in 12%, fatigue in 17% and dizziness in 5%, a total of 34% of `worst' symptoms. Sensory symptoms were present in patients with early disease and without disability as often as in disabled patients and in those with longer disease duration. There was however a strong correlation between the total number of sensory symptoms reported and the presence of disability in the MS patients. Conclusions: Sensory symptoms are common in MS patients. Pain syndromes, transient neurologic events, Lhermitte's phenomenon, fatigue, respiratory symptoms and vertigo were present significantly more frequently in patients with MS than in a control population and contributed to subjective morbidity. Future clinical trials assessing therapy in MS might include sensory symptoms as secondary endpoints to capture this `hidden reservoir' of disease morbidity.