Frontal variant of Alzheimer's disease and typical Alzheimer's disease: A comparative study

Clinical heterogeneity is one of the characteristics of Alzheimer's disease (AD). Hence, the atypical frontal or dysexecutive presentation is becoming increasingly well-known, although the underlying factors are still unknown. In this study, the neuropsychological performance of two groups of patients with AD (frontal variant-ADfv-and typical-TAD) were compared. The ADfv group (n = 13) was selected due to the existence of frontal hypoperfusion on a simple photon emission computer tomography (SPEC. The results revealed that the ADfv group displayed a severe dysexecutive disorder, more severe neuropsychiatric symptomatology (disinhibition and apathy), more functional impairment, and it generated a higher caregiver overload than the TAD group without frontal impairment (n = 47). Despite the facts that the ADfv group's performance was poorer in all the neuropsychological tests, significant group differences were only found in the processing speed and visuoconst.ruction tasks. Logistic regression analysis revealed that the processing speed and mental flexibility scores significantly predicted a diagnosis of ADfv. The existence of the grasp reflex, anosognosia, and the absence of apolipoprotein E epsilon 4 allele (APOE e4) were also more prevalent in the ADfv group. This group had a predominance of males and it was more likely to have a positive family history of AD. To conclude, the study suggests that ADfv represents a subtype of AD that seems to have different clinical, neuropsychological, and genetic characteristics from TAD.