| Motor impersistence | Inability to maintain sustained postures |
| Motor weakness | Often coexists with weakness on the affected side |
| Cognitive changes | May accompany cognitive impairment in neurodegenerative cases |
| Non-ketotic hyperglycemia | Increasingly recognized cause in elderly patients |
| Wilson disease | Copper accumulation |
| Databases | OMIMOrphanetClinicalTrialsPubMed |