Examining Frontal Lobe Asymmetry and Its Potential Role in Aggressive Behaviors in Early Alzheimer's Disease.

Background: Neuropsychiatric symptoms (NPS) in patients with dementia lead to caregiver burdens and worsen the patient's prognosis. Although many neuroimaging studies have been conducted, the etiology of NPS remains complex. We hypothesize that brain structural asymmetry could play a role in the appearance of NPS. Objective: This study explores the relationship between NPS and brain asymmetry in patients with Alzheimer's disease (AD). Methods: Demographic and MRI data for 121 mild AD cases were extracted from a multicenter Japanese database. Brain asymmetry was assessed by comparing the volumes of gray matter in the left and right brain regions. NPS was evaluated using the Neuropsychiatric Inventory (NPI). Subsequently, a comprehensive assessment of the correlation between brain asymmetry and NPS was conducted. Results: Among each NPS, aggressive NPS showed a significant correlation with asymmetry in the frontal lobe, indicative of right-side atrophy (r = 0.235, p = 0.009). This correlation remained statistically significant even after adjustments for multiple comparisons (p < 0.01). Post-hoc analysis further confirmed this association (p < 0.05). In contrast, no significant correlations were found for other NPS subtypes, including affective and apathetic symptoms. Conclusions: The study suggests frontal lobe asymmetry, particularly relative atrophy in the right hemisphere, may be linked to aggressive behaviors in early AD. These findings shed light on the neurobiological underpinnings of NPS, contributing to the development of potential interventions.

Risk factors of frontotemporal dementia compared with Alzheimer disease: Single psychiatric hospital-based research in Japan.

AIM: The objective of this study was to reveal risk factors for incident of frontotemporal dementia (FTD) compared with Alzheimer disease (AD) in Japan. METHOD: Fifty consecutive subjects diagnosed with FTD according to the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) under 75 years old were included retrospectively. As a control group, 48 subjects who were diagnosed with AD according to the DSM-5 and matched by age, sex, educational history, and Mini-Mental State Examination were also included. In order to examine the distinctive risk factors of FTD, we compared the relationship between symptomatologic features, Clinical Dementia Rating, clinical factors, and sociopsychological factors in the two groups. RESULT: Patients with FTD were more likely than patients with AD to have meticulous premorbid personality and less likely to have a history of diabetes than patients with AD. Although the regression analysis was not significant, a history of psychiatric disorders tends to affect the incidence of FTD. CONCLUSIONS: These findings regarding the risk of FTD are expected to lead to early diagnosis and care of FTD. Geriatr Gerontol Int 2023; 23: 932-937.

The Diagnostic Patterns of Referring Physicians and Hospital Expert Psychiatrists Regarding Particular Frontotemporal Lobar Degeneration Clinical and Neuropathological Subtypes.

BACKGROUND: It is important to make accurate clinical diagnosis of frontotemporal lobar degeneration (FTLD), which in turn, leads to future therapic approaches. The FTLD cases are frequently inaccurately identified, but the frequency of this misidentification according to the underlying pathological subtypes is still unclear. OBJECTIVE: We aimed to quantify the accuracy of behavioral variant frontotemporal dementia (bvFTD) and semantic variant primary progressive aphasia (svPPA) diagnoses by both the patients' referring physicians and hospital expert psychiatrists, and we investigated whether the physicians' and psychiatrists' diagnostic patterns are associated with a specific neuropathology. METHODS: We retrospectively analyzed the cases of a series of Japanese patients with pathologically diagnosed FTLD (n = 55): the bvFTD group (n = 47) consisted of patients with FTLD-tau (n = 20), FTLD-TDP (TAR DNA-binding protein of 43-kDA) (n = 19), and FTLD-FUS (fused in sarcoma) (n = 8). The svPPA patients (n = 8) all had FTLD-TDP. RESULTS: Only 31% of the patients' referring physicians mentioned FTD syndrome. The referring psychiatrists and neurologists showed similar diagnostic accuracy. High diagnostic accuracy was observed for the TDP pathology group (mainly svPPA patients). The FTLD-FUS patients were more likely to be diagnosed as having a psychiatric disorder by referring physicians. The hospital expert psychiatrists' accuracy for identifying FTLD-tau pathology was low. CONCLUSION: The results of our analyses revealed a specific diagnostic pattern associated with particular FTLD pathological subtypes, which will help to improve non-specialists' diagnostic ability.