Atrophy of the entorhinal cortex (ERC) can differentiate Parkinson disease (PD) patients with dementia from those with normal cognition, according to a report published in Movement Disorders. MRI scans revealed that patients with PD dementia had significantly smaller ERC volumes than did cognitively normal patients with PD. By contrast, hippocampal volumes were found to be similar between the two groups. These findings indicate that ERC atrophy could be a specific biomarker for dementia in PD.