Stage 3 – Executive dysfunction, such as impaired ability to organize thoughts and make decisions, and cognitive impairment. Stage 4 – Dementia, difficulty finding words and aggression. [cbc.ca]

impairment, so stated G31.85 Corticobasal degeneration G31.89 Other specified degenerative diseases of nervous system G31.9 Degenerative disease of nervous system, unspecified G32 Other degenerative disorders of nervous system in diseases classified [icd10data.com]

Moreover, Cambridge neuropsychologists also invented a cognitive test that predicts the diagnosis of Alzheimer's disease in patients with mild cognitive impairment. [neuroscience.cam.ac.uk]

Mitochondrial disorders, cognitive impairment and dementia. J Neurol Sci 2009;283:143–148. PubMed CrossRef Google Scholar 118. Finsterer J. Inherited mitochondrial neuropathies. J Neurol Sci 2011;304:9–16. PubMed CrossRef Google Scholar 119. [doi.org]

Signs & Symptoms Signs and symptoms of many degenerative disorders of the spine include pain in the back or neck and in the arms or legs, numbness, tingling, weakness, paralysis, muscle wasting, and abnormal reflexes. [orthoneuro.com]

Signs and symptoms include difficulty walking, sensory disturbances, lack of motor coordination and abnormal reflexes in the limbs. (NCIt) Hemiballismus : violent, flailing movements of a limb. [richardsonthebrain.com]