Morphological classification and changes in dementia (Review)

Effectiveness of brain magnetic resonance imaging in the early diagnosis and characterization of dementias; a systematic review

INTRODUCTION

Magnetic resonance imaging (MRI) is a frequently used test in the diagnosis of dementia. The objective was to evaluate its effectiveness for the early diagnosis of dementia in patients with mild cognitive impairment (MCI).

MATERIAL AND METHODS

Original studies were selected from systematic reviews between 2011 and 2021, according to PRISMA 2020 criteria. QUADAS-2 and GRADE tools were used, and a meta-analysis was performed.

RESULTS

Final selection of 23 articles. Patient selection and index test had a high probability of bias. The certainty of the evidence was very low. In the hippocampus, sensitivity was 0.62 (95%CI 0.48-0.79) and specificity 0.70 (95%CI 0.55-0.80). In the temporal lobe, sensitivity was 0.65 (range 0.45) and specificity 0.69 (range 0.32).

CONCLUSIONS

There is insufficient evidence to recommend routine brain MRI for the early diagnosis of dementia in patients with MCI.

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.