BRIDGING THE GAP BETWEEN NEUROLOGY AND PSYCHIATRY- PSYCHIATRIC SYMPTOMS IN THE COURSE OF NEURODEGENERATIVE DISORDERS

Abstract

It is increasingly recognized that there is significant heterogeneity in phenotype and clinical trajectories in Alzheimer's disease as well as Lewy Body and Vascular dementia. Relatively common neurodegenerative disorder, Lewy Body Dementia (LBD) presents with psychiatric features. Mood disorders are common and often precede core symptoms of LBD. Patient with LBD especially early in the course of disease are at increased risk for suicide. Psychosis is one of the most debilitating symptoms of LBD as it is an independent risk factor for nursing home placements, increased caregiver distress and mortality. Visual hallucinations are the most common psychotic manifestation in LBD. Auditory, olfactory, tactile and gustatory hallucinations and delusions are less frequently found. Global cognitive deficits including attention, frontal executive dysfunction, visuospatial abnormalities, language and verbal memory were associated with the presence of psychosis in Lewy Body Dementia. Glucocerebrosidase gene (GBA) mutations and polymorphisms found to be associated with LBD. Up to 25% of Alzheimer's disease (AD) cases do not show the typical neuropathology. Subtypes and atypical non-amnestic AD presentations have been formalized in the International Working Group (IWG) clinical diagnosis criteria. Frontal signs and symptoms are often seen in Alzheimer's disease especially in patients with early onset. In those clinical situations differential diagnosis especially distunguising between Clinical diagnosis of atypical AD has significantly been improved by the availability of biomarkers, including cerebrospinal fluid levels of Aβ42, total tau and phosphorylated tau181. MRI volumetric estimation of hippocampal and medial temporal atrophy, and amyloid brain PET imaging. We will review atypical forms of AD from these varied perspectives to help improve diagnostic confidence among clinicians. Cerebral amyloid angiopathy (CAA) is a highly prevalent pathologic finding in the elderly contributing to cognitive loss, neuropsychiatric symptoms and morbidity. It is characterized by predominantly vascular deposition of beta amyloid protein Its prevalence varies across different populations. Initially conceptualized as vascular dementia syndrome CAA was proved to overlap with AD pathology and is thought to affect over 80% of AD patients. Lobar intracerebral hemorrhage and infarction are the well-known striking clinical manifestations, but CAA has multiple other clinical phenotypes: Inflammatory disease in the form of vasculitis known as amyloid beta related angiitis (ABRA) and inflammatory leukoencephalopathy, also known as CAA related inflammation (CAA-RI). Due to multiple clinical phenotypes CAA remains clinically underdiagnosed and underreported especially in elderly with dementia and other psychiatric symptoms. The underlying pathophysiological mechanism for the spectrum of CAA will be discussed