ataxia vs neurological disorder

ataxia and neurological disorder both are nouns.

Word	Noun	Adjective	Verb	Adverb
ataxia	Yes	No	No	No
neurological disorder	Yes	No	No	No

As nouns, neurological disorder is a hypernym of ataxia; that is, neurological disorder is a word with a broader meaning than ataxia:

ataxia: inability to coordinate voluntary muscle movements; unsteady movements and staggering gait
neurological disorder: a disorder of the nervous system

Other hypernyms of ataxia include nervous disorder, neurological disease.

ataxia (noun)	neurological disorder (noun)
inability to coordinate voluntary muscle movements; unsteady movements and staggering gait	a disorder of the nervous system