Etiology of Syncope and Unexplained Falls in Elderly Adults with Dementia: Syncope and Dementia (SYD) Study.

OBJECTIVES To investigate the etiology of transient loss of consciousness (T-LOC) suspected to be syncope and unexplained falls in elderly adults with dementia. DESIGN Prospective, observational, multicenter study. SETTING Acute care wards, syncope units or centers for the diagnosis of dementia. PARTICIPANTS Individuals aged 65 and older with a diagnosis of dementia and one or more episodes of T-LOC of a suspected syncopal nature or unexplained falls during the previous 3 months were enrolled. MEASUREMENTS The causes of T-LOC suspected to be syncope and unexplained falls were evaluated using a simplified protocol based on European Society of Cardiology guidelines. RESULTS Of 357 individuals enrolled, 181 (50.7%) had been referred for T-LOC suspected to be syncope, 166 (46.5%) for unexplained falls, and 10 (2.8%) for both. An initially suspected diagnosis of syncope was confirmed in 158 (87.3%), and syncope was identified as the cause of the event in 75 (45.2%) of those referred for unexplained falls. Orthostatic hypotension was the cause of the event in 117 of 242 (48.3%) participants with a final diagnosis of syncope. CONCLUSION The simplified syncope diagnostic protocol can be used in elderly people with dementia referred for suspected syncope or unexplained falls. Unexplained falls may mask a diagnosis of syncope or pseudosyncope in almost 50% of cases. Given the high prevalence of orthostatic syncope in participants (~50%), a systematic reappraisal of drugs potentially responsible for orthostatic hypotension is warranted.