Fist-Edge-Palm (FEP) test has a high sensitivity in differentiating dementia from normal cognition in Parkinson's disease

The Fist-Edge-Palm (FEP) test takes 0.5-3 min to complete and is highly sensitive in differentiating Alzheimer's disease and frontotemporal dementia from normal cognition, but it has not yet been studied in Parkinson's disease (PD).To determine the sensitivity and specificity of the FEP test in screening patients with PD for cognitive impairment and dementia.PD patients were recruited and divided into three groups based on cognitive status: normal cognition, mild cognitive impairment (MCI) and dementia according to 2015 MDS clinical diagnostic criteria for PD and clinical dementia rating scale (CDR) assessment for cognitive status. MMSE, FEP and clock drawing test (CDT) were tested in all recruited PD patients. Chi-square test was used to compare the sensitivity of FEP and CDT in detecting PDD and PD-MCI.A total of 108 PD patients were included: 52 normal cognition, 28 MCI, and 28 dementia. The sensitivity of FEP in differentiating PDD from PD-NC was 96.4% and the sensitivity for PD-MCI from PD-NC was 71.4%. The sensitivity of CDT in differentiating PDD from PD-NC was 71.4% and PD-MCI from PD-NC was 53.6%. The sensitivities of FEP and CDT were 83.9% and 62.5%, respectively, in identifying cognitive impairment (CDR ≥ 0.5) in PD patients.FEP is a sensitive screening tool in differentiating PDD or PD-MCI from PD-NC, and it is much faster than MMSE and more sensitive than CDT. FEP may be a practical screening tool for daily clinical practice.