Background Mild cognitive impairment (MCI) is a heterogeneous syndrome with variable dementia progression. Neuropsychiatric symptoms (NPS) can accompany MCI and may reflect emerging neurodegenerative disease. We describe the NPS profile and dementia progression in amnestic (aMCI) and non-amnestic MCI (nMCI).
Methods Descriptive cohort study within a hospital-based Memory Clinic. Clinicodemographic and medical data were extracted from medical records for consecutive patients with MCI. NPS were assessed using the Neuropsychiatric Inventory and clinical diagnosis made following multidisciplinary assessment with standard investigations.
Results One-hundred and nine patients with MCI were included, median[IQR] age 80 years[75-85], 53% female, median(IQR) baseline MMSE 24(19-26). Ninety-eight (90%) experienced at least one NPS, the commonest domains being anxiety (54%), depression (49%) and emotional lability (39%).
Fifty eight patients (53%) were classified as aMCI and 51 (47%) as nMCI. nMCI patients experienced more depression (61% vs 38%), hallucinations (16% vs 0%) and apathy (22% vs 9%). Other NPS were more equally distributed.
Over a median follow-up of 1.08 years (IQR 0.61-1.74), 55/109 (49%) participants with MCI progressed to dementia including 30/58 (51%) with aMCI and 23/51 (45%) with nMCI. The most common form of dementia emerging in those with initial aMCI was Alzheimer’s dementia (20/30, 67%) whereas nMCI had more varied outcomes. No individual NPS was associated with progression to dementia.
Conclusions NPS profiles differ between MCI subgroups with depression, hallucinations and apathy more common in nMCI suggesting potential association with non-Alzheimer’s pathology. Incorporating NPS assessment into care may better discriminate MCI subgroups to inform prognosis and treatment.