Impact of Limb Phenotype on Tongue Denervation Atrophy, Dysphagia Penetrance, and Survival Time in a Mouse Model of ALS.

This is a mouse ALS model, not a human treatment study, so it cannot change swallowing care for people with ALS. The forelimb-involving group was very small at first, with only 5 mice, and 8 more were added later. Six of the 44 mice did not drink during swallowing testing and were excluded from the main swallowing analysis. Histological analysis used only 16 mice, including 4 hindlimb-only and 4 forelimb-involving ALS mice. Only the posterior part of one tongue muscle was examined. Swallowing and muscle changes were measured only at disease end-stage, not early in the disease. The humane endpoint was 15 to 20% weight loss, and mice could still eat and drink, which may affect survival comparisons. The authors combined two forelimb-involving patterns into one mixed phenotype group, which may hide differences between subtypes. Limb phenotype was not predictable from the breeder phenotype; offspring were assigned by chance at about 50%.

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Do not apply these mouse dysphagia percentages to people with ALS. The study did not test treatment in patients, and the tongue muscle findings were measured in a small animal model.