Research has shown that cats with laryngeal paralysis are unable to produce the purring noise.
Laryngeal diphtheria, which involves the voice box or larynx, is the form most likely to produce serious complications.
This indicates some sort of bodily response that is more than likely linked to vibrations of the laryngeal muscles.
People with laryngeal diphtheria are kept in a croup tent or high-humidity environment; they may also need throat suctioning or emergency surgery if their airway is blocked.
His name is especially connected with the first description of locomotor ataxy, progressive muscular atrophy, pseudo-hypertrophic paralysis, glosso-labio laryngeal paralysis and other nervous troubles.