The 12 year prognosis of unilateral functional weakness and sensory disturbance.

BACKGROUND: Although the symptoms of unilateral "medically unexplained" or "functional" weakness and sensory disturbance present commonly to neurologists, little is known about their long term prognosis.
OBJECTIVE: To determine the long term outcome of functional weakness and sensory disturbance. PATIENTS: A previously assembled cohort of 60 patients seen as inpatients by consultant neurologists in Edinburgh between 1985 and 1992 and diagnosed as having unilateral functional weakness or sensory disturbance.
METHODS: Current symptoms, disability, and distress were assessed by postal questionnaire to the patients and their family doctors.
RESULTS: Follow up data relating to mortality were obtained in 56 patients (93%) and to current diagnosis in 48 patients (80%). Patient questionnaire data were obtained in 42 patients (70%). The median duration of follow up was 12.5 years (range 9 to 16). Thirty five of the 42 patients (83%) still reported weakness or sensory symptoms, and the majority reported limitation of physical function, distress, and multiple other somatic symptoms. Twenty nine per cent had taken medical retirement. An examination of baseline predictors indicated that patients who had sensory symptoms had better functioning at follow up than those who had weakness. Only one patient had developed a neurological disorder which, in hindsight, explained the original presentation. Another patient had died of unrelated causes.
CONCLUSIONS: Many patients assessed by neurologists with unilateral functional weakness and sensory symptoms as inpatients remain symptomatic, distressed, and disabled as long as 12 years after the original diagnosis. These symptoms are only rarely explained by the subsequent development of a recognisable neurological disorder in the long term.