Cognitive Training With and Without tDCS to Improve Cognition in HIV

The purpose of this study is to develop pilot data on the potential efficacy of computer-based cognitive training or the combination of computer-based cognitive training with transcranial direct current stimulation (tDCS) in improving cognitive function in persons with HIV-related mild neurocognitive disorder (MND).

The purpose of this study is to develop pilot data on the potential efficacy of computer-based cognitive training or the combination of computer-based cognitive training with transcranial direct current stimulation (tDCS) in improving cognitive function in persons with HIV-related mild neurocognitive disorder (MND). tDCS is a noninvasive brain stimulation technique in which a small direct current (1-2 mA) is applied to the scalp during a cognitive or motor activity, inducing a very small current that affects specific neural circuits related to the site at which electrodes are placed. tDCS has been judged safe and has shown significant treatment effects in studies with other populations, but has not been extensively studied in individuals with HIV infection. tDCS has been shown to facilitate learning in a number of studies, suggesting that it may improve or enhance learning in those with cognitive problems. As HIV infection is associated with decrements in a number of cognitive skills, including working memory, executive functions, and psychomotor speed that are related to individuals' functional status and medication adherence, the demonstration of a technique to enhance the effects of cognitive training in this population would have substantial clinical benefits as well as scientific value.

Direct current stimulation at a current of 1.5 mA with anode at F3 (left dorsolateral prefrontal cortex) and cathode at Fp2 (right frontal pole) for a period of 20 minutes each for 6 sessions over two weeks simultaneously with cognitive training.

Computer delivered intervention designed to improve cognitive speed and executive functioning for a period of 20 minutes each for 6 sessions over two weeks.

Direct current stimulation at a current of 1.5 mA with anode at F3 (left dorsolateral prefrontal cortex) and cathode at Fp2 (right frontal pole) for a period of one minute to simulate active treatment applied in 6 sessions over two weeks.

Participants' rate of improvement on a verbal working memory task. Participants completed a battery of cognitive measures administered by an evaluator blind to treatment assignment. We used the Digits Backward trial of the Digit Span subtest of the Wechsler Adult Intelligence Scale Fourth Edition (WAIS-IV; Pearson Assessment) to measure working memory. We used raw scores for analyses. These are the largest number of digits the participant could remember and repeat in reverse order. Possible range of scores is from zero to 10. Normal persons typically remember from 5 to 7 digits. Higher scores are considered better. Analysis results are overall estimated marginal means from repeated measures analysis of covariance with treatment group as a fixed factor and age, gender, race, education, helper T cell count, and log viral load as covariates.

Participants' mood over the course of the study. We used the Center for Epidemiological Studies--Depression scale (CES-D) to measure mood. This measure includes 20 items that ask the person assessed to report his or her experience of mood symptoms over the past two weeks. Participants completed this measure before and after the study intervention. Scores can range from zero to 60, with most persons attaining a score of 15 or less. Higher scores are considered worse as they indicate more frequent or more severe mood symptoms.

Patient report of cognitive difficulties on the Patient Assessment of Own Functioning. This scale comprises 33 items describing problems in thinking, language, and memory. Participants rate each items according to how often they experience each problem on a six-point scale from "almost never" (score of 0) to "almost always" (score of 5). The participant's score is the sum of ratings on all items. The range of possible scores on each item is from 0 to 5, with most persons achieving a score of 1.5 or lower. Higher scores represent more frequent report of cognitive difficulties and thus are considered worse. The range of all possible scores for the full scale of 33 items is is 0 to 165.

Inclusion Criteria: 18 years of age or older Fluent in English Meets Frascati criteria for mild neurocognitive disorder Exclusion Criteria: Left handed Presence of dementia Use of specific psychotropic medications including antidepressants, antipsychotics, and sleep-promoting medications