A systematic review and meta-analysis of dual-task outcomes in subjective cognitive decline

Subjective cognitive decline (SCD) may represent a preclinical manifestation of objective cognitive impairment. This review consolidated existing findings to determine if dual-tasks objectively differentiate between individuals with SCD, motoric cognitive risk syndrome (MCR), mild cognitive impairment (MCI), and dementia. MEDLINE, Embase, PsycINFO, CENTRAL, AgeLine, and CINAHL were systematically searched for dual-task studies examining older adults with SCD and analyzed using random-effects meta-analyses. Thirteen studies met the inclusion criteria. Within the SCD group, faster gait speed (SMD, 1.35; 95% CI, 0.57-2.13; p = .0007) and longer step length (SMD, 0.85; 95% CI, 0.44-1.26; p < .0001) favored the single compared to dual-task condition. Faster gait speed was observed in the SCD group compared to MCI (SMD, 0.48; 95% CI, 0.28-0.67; p = .0001). A standardized dual-task approach is needed to track gait parameters longitudinally, beginning with changes occurring at the SCD stage as these may precede future cognitive impairments.

Evidence demonstrates that SCD may be a precursor to dementia.Faster dual-task gait speed was observed in the SCD group compared to MCI.Slower dual-task gait speed and shorter step length were observed within the SCD group.Dual-tasks may help differentiate between preclinical and clinical cognitive decline.Dual-tasks should be standardized and changes should be tracked longitudinally.