Prevalence and characteristics of pain in early and late stages of ALS

The purpose of this study was to compare pain frequency in early and late stages of ALS and to describe the relationship between pain intensity and functional status. Sixty-four patients in different stages of ALS were asked to complete the Neuropathic Pain Scale and to draw the localization of their pain on a body cartoon. The Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) and Forced Vital Capacity (FVC) values were obtained from the medical record. A χ² correlation was used to compare the proportion of patients with pain in different stages of ALS. Correlation coefficient was used to describe the relationship between pain intensity and functional status (ALSFRS-R). Pain was reported by about half the patients. Using FVC values, patients were subdivided into early, intermediate and late stage of the disease. There was a negative correlation between pain intensity and functional status. There was no statistically significant difference in the presence of pain among patients in the different stages of ALS. In conclusion, our study showed that pain is common in ALS patients. Although pain intensity did correlate negatively with functional status, as expected, we were surprised to find that pain was also present in the early stages of the disease.