Characteristics of pain in amyotrophic lateral sclerosis

Background: Pain is an often underestimated and neglected symptom in amyotrophic lateral sclerosis (ALS). Methods: In a cross-sectional survey, 46 patients with ALS, 46 age- and gender matched population-based controls, and 23 diseased controls with myotonic dystrophy type 2 (DM2) were screened for occurrence, type, distribution, and treatment of pain and cramps. Data were collected with the use of the short form brief pain inventory (BPI). Results: Pain was reported in 78% of ALS patients, 79% of DM2 patients, and 54% of controls (P < 0.05). More ALS patients than controls reported moderate to severe pain (42% vs. 20%). Pain in ALS patients interfered significantly more with daily activities than in controls (median pain interference score: 3.0 vs. 1.2, P < 0.05), especially enjoyment of life (5.0 vs. 1.0) and mood (3.0 vs. 1.0). There was no correlation between the duration of the disease and the severity of pain. Movement-induced cramps were reported in 63% of ALS patients, mostly in the distal extremities. There was no difference in the duration of ALS disease between patients reporting cramps and those who did not. Discussion: Our study showed that pain was a relatively frequent symptom which had an important impact on the quality of life. Pain that requires treatment can occur at every stage of ALS.