When is treatment with DMC useful for ALS?

Previous clinical studies and practical experience with dextromethorphan/quinidine (DMC) have shown an optimal response with a mild or moderate speech disorder. This corresponds to a grading on the ALS Functional Rating Scale (ALSFRS-R-SE) of 3 scale points (“perceptible speech disorder”) or 2 scale points (“repetition necessary for understanding”) for question 1 of the scale, which relates to speech. No effect on speech function is to be expected in the case of a more severe speech disorder. In this situation, DMC can be discontinued. Some patients nevertheless report a positive effect on swallowing function – in this constellation, treatment with DMC can be continued.