Regional Atrophy of the Insular Cortex Is Associated with Neuropsychiatric Symptoms in Alzheimer's Disease Patients

Abstract

Background: Alzheimer's disease (AD) is a devastating illness that results in progressive cognitive decline and neuropsychiatric symptoms. The neuropsychiatric symptoms are associated with a rapid decline in cognition and activities of daily living and increased mortality, however the neuroanatomical localisation involved in the development of neuropsychiatric symptoms remains poorly understood. The aim of this study was to identify the association with the regional volume of the insular cortex and each neuropsychiatric symptom in patients with AD. Methods: Subjects diagnosed with AD (n = 40) were evaluated. Magnetic resonance images were obtained and the insular cortex was subdivided into four subregions through the central sulcus of the insula and bilaterally: right anterior insular cortex, right posterior insular cortex, left anterior insular cortex and left posterior insular cortex. The neuropsychiatric symptoms were assessed using the Neuropsychiatric Inventory. A partial correlation analysis was performed. Results: A significant negative correlation existed between apathy, the irritability subscale score and the volume ratio of the bilateral anterior insular cortex and right posterior insular cortex (r = -0.457, -0.433 and -0.572, respectively, p = 0.032, 0.044 and 0.005, respectively). Conclusion: The findings suggest that the regional atrophy of the insular cortex is associated with neuropsychiatric symptoms in AD patients.