Objective: Data on early-onset dementia in Chinese is limited. This study aimed to report the diagnostic profiles and characteristics of patients with early-onset dementia in a university-affiliated cognitive disorder clinic in Hong Kong. Methods: We prospectively collected data of consecutive patients who were referred between January 2012 and December 2018. All patients were referred for diagnostic evaluation of cognitive symptoms. Patients with symptom-onset at age 65 or before were recruited. We excluded patients with (1) cognitive deficits referable to an isolated event or toxin and (2) significant mood disorders. Results: Of the 93 patients included, four patients had temporal lobe epilepsy mimicking dementia. Three patients had cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), one patient had Niemann-Pick disease type C and two patients had undetermined aetiology. The remaining 83 patients had primary degenerative dementia. The most frequent diagnosis wasAlzheimer’s disease (AD) (70%), followed by frontotemporal dementia (FTD) (22%) and parkinsonian disorders (8%). The mean age of symptom onset was 57.8 ± 5.8 years.Ten (17%) AD patients had non-amnestic presentation. Fifteen FTD patients consented for mutation screening in the GRN (progranulin), MAPT (microtubule-associated protein tau) and C9orf72 genes, none were positive. Conclusions: Early-onset dementia had a broader differential diagnoses than late-onset dementia, and includes a number of rare hereditary diseases. Patients with suspected early-onset dementia should be thoroughly evaluated to identify any treatable causes.

Age-related sporadic cerebral small vessel disease (CSVD) has gained increasing attention over the past decades because of its increasing prevalence associated with an aging population. The widespread application of and advances in brain magnetic resonance imaging in recent decades have significantly increased researchers' understanding in the in vivo evolution of CSVD, its impact upon the brain, its risk factors, and the mechanisms that explain the various clinical manifestation associated with sporadic CSVD. In this review, we aimed to provide an update on the pathophysiology, risk factors, biomarkers, and the determinants and spectrum of the clinical manifestation of sporadic CSVD.
Aged ; Aging ; Brain/diagnostic imaging* ; Cerebral Small Vessel Diseases/epidemiology* ; Humans ; Magnetic Resonance Imaging ; Pandemics