ALS Functional Rating Scale - Revised

Criteria

ALSFRS-R includes 12 questions that can have a score of 0 to 4. A score of 0 on a question would indicate no function while a score of 4 would indicate full function. This scale has been useful for doctors in diagnosing patients, measuring disease progression and also for researchers when selecting patients for a study and measuring the potential effects of a clinical trial.

The ALSFRS-R scale has some limitations though since it is not useful to compare scores of people who present with different onset. In ALS the main type of onset is bulbar followed by limb-onset ALS which describes the region of motor neurons first affected. Individuals may also present with respiratory-onset ALS, but this occurs very rarely. Since there are three different types of ALS, ALSFRS-R scores are often grouped in categories depending on type of onset.

Since there are three main pathways of progression, the questions are also divided in relation to the types of onset. Questions 1 to 3 are related to bulbar onset, questions 4 to 9 are related to limb onset and questions 10 to 12 are related to respiratory onset. Further developments of the ALSFRS-R include an extended version (ALSFRS-EX) to mitigate the floor effect and a version with explanatory notes, which is particularly suitable for self-assessment (ALSFRS-R-SE, self-explanatory) and has a strong agreement with the harmonized SOP for interview-based assessment.