A randomized controlled trial of cognitive training using a visual speed of processing intervention in middle aged and older adults

Abstract

BACKGROUND: Age-related cognitive decline is common and may lead to substantial difficulties and disabilities in everyday life. We hypothesized that 10 hours of visual speed of processing training would prevent age-related declines and potentially improve cognitive processing speed., METHODS: Within two age bands (50-64 and > 65) 681 patients were randomized to (a) three computerized visual speed of processing training arms (10 hours on-site, 14 hours on-site, or 10 hours at-home) or (b) an on-site attention control group using computerized crossword puzzles for 10 hours. The primary outcome was the Useful Field of View (UFOV) test, and the secondary outcomes were the Trail Making (Trails) A and B Tests, Symbol Digit Modalities Test (SDMT), Stroop Color and Word Tests, Controlled Oral Word Association Test (COWAT), and the Digit Vigilance Test (DVT), which were assessed at baseline and at one year. 620 participants (91%) completed the study and were included in the analyses. Linear mixed models were used with Blom rank transformations within age bands., RESULTS: All intervention groups had (p<0.05) small to medium standardized effect size improvements on UFOV (Cohen's d = -0.322 to -0.579, depending on intervention arm), Trails A (d = -0.204 to -0.265), Trails B (d = -0.225 to -0.320), SDMT (d = 0.263 to 0.351), and Stroop Word (d = 0.240 to 0.271). Converted to years of protection against age-related cognitive declines, these effects reflect 3.0 to 4.1 years on UFOV, 2.2 to 3.5 years on Trails A, 1.5 to 2.0 years on Trails B, 5.4 to 6.6 years on SDMT, and 2.3 to 2.7 years on Stroop Word., CONCLUSION: Visual speed of processing training delivered on-site or at-home to middle-aged or older adults using standard home computers resulted in stabilization or improvement in several cognitive function tests. Widespread implementation of this intervention is feasible., TRIAL REGISTRATION: ClinicalTrials.gov NCT-01165463.