Supplementary Material for: Neuronal Intranuclear Inclusion Disease Presenting with Resting Tremor

Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disease with various neurological symptoms. A 73-year-old woman presented with slowly progressive tremor in both hands. The resting tremor was enhanced by cognitive activity and walking. However, there were no other signs of parkinsonism. Levodopa and trihexyphenidyl were ineffective against the tremor. A diagnosis of NIID was made based on skin biopsy findings. The tremor in this case was very similar to that seen in Parkinson's disease (PD). Previous reports and the present case indicate that NIID patients can develop tremor that is similar in character to that seen in PD. NIID should be considered in the differential diagnosis of resting tremor similar to PD.