A pilot study of cognitive training with and without transcranial direct current stimulation to improve cognition in older persons with HIV-related cognitive impairment

BACKGROUND: In spite of treatment advances, HIV infection is associated with cognitive deficits. This is even more important as many persons with HIV infection age and experience age-related cognitive impairments. Both computer-based cognitive training and transcranial direct current stimulation (tDCS) have shown promise as interventions to improve cognitive function. In this study, we investigate the acceptability and efficacy of cognitive training with and without tDCS in older persons with HIV. PATIENTS AND METHODS: In this single-blind randomized study, participants were 14 individuals of whom 11 completed study procedures (mean age =51.5 years; nine men and two women) with HIV-related mild neurocognitive disorder. Participants completed a battery of neuropsychological and self-report measures and then six 20-minute cognitive training sessions while receiving either active or sham anodal tDCS over the left dorsolateral prefrontal cortex. After training, participants completed the same measures. Success of the blind and participant reactions were assessed during a final interview. Assessments were completed by an assessor blind to treatment assignment. Pre- and post-training changes were evaluated via analysis of covariance yielding estimates of effect size. RESULTS: All participants believed that they had been assigned to active treatment; nine of the 11 believed that the intervention had improved their cognitive functioning. Both participants who felt the intervention was ineffective were assigned to the sham condition. None of the planned tested interactions of time with treatment was significant, but 12 of 13 favored tDCS (P=0.08). All participants indicated that they would participate in similar studies in the future. CONCLUSION: Results show that both cognitive training via computer game playing and tDCS were well accepted by older persons with HIV infection. Results are suggestive that tDCS may improve cognitive function in persons with HIV infection. Further study of tDCS as an intervention for HIV-related cognitive dysfunction is warranted.