The ALS Functional Rating Scale interrogates bulbar, motor and respiratory functions relevant to the strikingly variable phenotype of ALS

Measurement of change is an elusive clinical exercise that, in the absence of a biological marker, has been addressed by the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS), a scale based on symptom description.1 The ALSFRS has become a recognised standard for measurement in clinical trials, for entry into amyotrophic lateral sclerosis (ALS) databases and for assessment of prognosis. The ALSFRS was devised as a clinical tool using functional categories designed to mimic the clinical assessment of a patient with ALS; it was, indeed, a ‘back of an envelope’ product but based on extensive clinical experience. Since the functional categories within each subset replicate clinical assessment, the ALSFRS has proved reproducible and relevant, with good construct validity, and acceptable test–retest reliability. The original ALSFRS consists of 10 sets of 5 questions, each representing a different clinical domain relevant to ALS, scored from 0 to 4, where 4 is normal function. These domains consist of 3 bulbar sets (speech, salivation and swallowing—12 points), 6 motor sets (3 upper …