ABSTRACT Aim To elucidate the pathophysiological mechanisms between neurocognition and neuropsychiatric sub‐symptoms in Alzheimer's disease (AD), the present cross‐sectional study compared severity of each subitem in a neuropsychiatric symptom (NPS) scale among four neurocognitive groups classified based on the pattern of executive and general cognitive function. Methods Of 546 consecutive outpatients who visited Memory Clinic at Jikei University Kashiwa Hospital, we selected 160 with AD and classified them into four neurocognitive groups based on score in the MMSE (Mini‐Mental State Examination: ≥ 21 point was general cognitive preserved) or FAB (Frontal Assessment Battery: ≥ 13 was executive cognitive preserved): BPC (both cognitive preserved); GCP (general cognitive preserved); ECP (executive cognitive preserved); NCP (neither cognitive preserved). We compared the severity of each subitem of the Behavioral Pathology in Alzheimer's Disease (Behave‐AD) scale among the four groups. Results Among seven subitems of Behave‐AD, the scores for diurnal rhythm disturbances and anxieties/phobias differed significantly among the four groups. The score for diurnal rhythm disturbances was significantly higher in GCP than BCP, and the score for anxiety/phobias was significantly higher in ECP than BCP. However, no significant difference was shown between each cognitive group and the NCP. Conclusion The general cognitive preservation without executive preservation may be relevant to the diurnal rhythm disturbances by self‐correction for own behavior, and the executive preservation without general cognition preservation may contribute to the transient anxiety as emotional reaction. Such dissociative relations between executive and general neurocognition may be relevant to specific neuropsychiatric sub‐symptoms emergence or severity in AD.
Okabe et al. (Thu,) studied this question.