Sumeng Song, Yajuan Li, Liangdong Lin, Lei Duan
Prolonged FVEP-P2 latency was observed in AD, with preliminary findings suggesting similar alterations in other forms or stages of cognitive impairment. These findings do not establish a specific neurobiological mechanism or diagnostic role. Further studies are needed to clarify the biological basis and clinical value of FVEP-P2 latency.
BACKGROUND: The flash visual evoked potential P2 component (FVEP-P2) has been investigated as a potential neurophysiological measure of cognitive impairment, but its biological and clinical significance remains uncertain. However, evidence remains fragmented. This systematic review and meta-analysis aimed to quantitatively synthesize evidence on FVEP-P2 latency alterations across the cognitive impairment continuum, including mild cognitive impairment (MCI) and major neurocognitive disorders (dementia).
METHODS: We systematically searched PubMed, Embase, Web of Science, and Cochrane Library until July 28, 2025. Standardized mean differences (SMDs) for FVEP-P2 latency were pooled from 21 studies (n = 1,778) using a random-effects model to compare AD, mild cognitive impairment (MCI), and VaD groups against healthy controls (HC). Subgroup and sensitivity analyses explored heterogeneity sources.
RESULTS: Twenty-one studies involving 1,778 participants were included. FVEP-P2 latency was significantly prolonged in patients with AD compared with healthy controls (18 comparisons, SMD = 1.55, 95% CI 1.05-2.05, I2 = 88.9%). Exploratory analyses also suggested prolonged latency in VaD (four comparisons; SMD = 1.44, 95% CI 0.35-2.53; I2 = 92.2%), MCI (two comparisons; SMD = 1.50, 95% CI 0.26-2.74; I2 = 53.8%), and PDD (one comparison; SMD = 1.44, 95% CI 0.63-2.25). In a restricted exploratory analysis excluding six selected AD comparisons, the association remained statistically significant and directionally consistent (SMD = 1.32, 95% CI 0.83-1.82; I2 = 84%). The ≥ 75-year subgroup showed lower heterogeneity (I2 = 41%), although differences between age subgroups were not statistically significant (p = 0.56). Funnel plot asymmetry and Egger's test suggested potential small-study effects in the AD analysis.
CONCLUSION: Prolonged FVEP-P2 latency was observed in AD, with preliminary findings suggesting similar alterations in other forms or stages of cognitive impairment. These findings do not establish a specific neurobiological mechanism or diagnostic role. Further studies are needed to clarify the biological basis and clinical value of FVEP-P2 latency.