Involuntary emotional expression disorder (IEED) in Parkinson's disease

IEED and depression are overlapping but distinct disorders in PD. IEED symptoms may occur in up to 15% of PD patients, but a disorder occurs in only half of those, suggesting that often IEED symptoms are not clinically significant in this population. The CNS-LS does not appear to be a good screening instrument for IEED in PD, in part due to its high correlation with depressive symptoms.