EARLY ONSET DEGENERATIVE DEMENTIAS: ETIOLOGICAL CLASSIFICATION AND DEMOGRAPHIC CHARACTERISTICS IN SERBIAN TERTIARY REFERRAL CENTER

Abstract

Early-onset dementia (EOD), conventionally considered to include patients with disease onset before 65 years of age, represents a major diagnostic challenge. Degenerative dementias (Alzheimer's disease (AD), frontotemporal dementia (FTD), Dementia with lewy bodies (DLB)), traditionally considered to affect older population, are a main cause of EOD as well. Our aim was to make etiological classification and to determine demographic characteristics of consecutive degenerative EOD patients. Between april 2012 and april 2017, 256 patients were reffered to Neurology Clinic, Clinical Centre of Serbia with the diagnosis of possible EOD. After detailed examination, 207 patients fulfilled current criteria for degenerative demetias- AD, FTD spectrum and DLB. In our investigated EOD cohort, 129(62,2%) patients were diagnosed with AD, 78(36,2%) with FTD spectrum and 3(1,4%) patients with DLB. According to dominant presenting cognitive symptom, AD patients were further classified into AD with amnestic presentation (95 patients, 73%) and non-amnestic presentation (34 patients, 27%). Among FTD spectrum, 60(75.6%) patients met criteria for behavioural variant (FTDbv), 13(16,7%) for primary progressive aphasia (PPA)-progressive nonfluent aphasia (PPA-PNFA) and 5(7.7%) for semantic variant of PPA. Furthermore, 5(2,4%) patients (all FTDbv) developed symptoms consistent with progressive supranuclear palsy, 5(2,4%) patients (1 FTDbv, 2 PPA-PNFA and 2 AD) had corticobasal syndrome and 4(1,9%) patients developed concomitant motor neuron disease (3 FTDbv, 1 PPA-PNFA) Demographic characteristics did not differ significantly among diagnostic categories in our EOD group. Degenerative disorders as causes of EOD are not rare. High clinical alertness is warranted to achieve correct and timely diagnosis.