Predictors of Improvement Following Speed of Processing Training in Middle-aged and Older Adults with HIV: A Pilot Study

Highly Active Antiretroviral Therapy (HAART) has radically reduced HIV-related mortality (Vance & Robinson, 2004), resulting in greater numbers of older adults with this disease. Based upon the Centers for Disease Control (CDC) and Prevention's 2005 data (CDC, 2008), adults 50 years and older in the United States comprised 15% of all new cases of HIV/AIDS, 24% of existing cases, and 35% of AIDS-related mortality. It is estimated by 2015 nearly half of those with HIV will be 50 and older (Kirk & Goetz, 2009), thus highlighting the need for research focused on the changes in cognition resulting from potential interactions of the disease and aging processes. More importantly, these statistics also highlight the growing need for research focused on interventions that can maintain the cognitive, and thus everyday functional abilities of this population. Cognitive Problems Associated with Aging with HIV Despite the effectiveness of HAART in extending life for those infected, concerns remain that as people age with this disease, many will experience more severe cognitive problems that will interfere with everyday functioning and quality of life (Valcour & Sacktor, 2004; Vance, Wadley, Crowe, Raper, & Ball, 2011). Heaton and colleagues (2010) examined neuropsychological functioning in several cognitive domains (e.g., attention/working memory, verbal fluency) including speed of processing. In this study of 1,555 adults with HIV (Mage = 43.2), 52% exhibited neuropsychological impairment. These researchers found that 33% of them had asymptomatic neurocognitive impairments, 12% had mild neurocognitive disorders, and 2% had severe HIV dementia. Other studies have found similar rates of neuropsychological impairments (e.g., Heaton et al., 2004; Trepanier et al., 2005). Impairments in speed of processing appear to be one of the cognitive domains most affected by HIV; these impairments may even be more profound in older adults aging with this disease (Reger, Welsh, Razani, Martin, & Boone, 2002). For example, in a longitudinal study, Baldwizcs and colleagues (2004) followed adults with (n = 59) and without (n = 55) HIV over an 8-year period. They found a significant decline in speed of processing in adults with HIV compared to those without the disease. Furthermore, Reger and colleagues conducted a meta-analysis of 41 studies on neuropsychological impairments of HIV infection. These researchers found those with HIV performed significantly worse on measures of problem solving and executive functioning, motor functioning, and speed of processing compared to those without HIV. In addition, it has been observed in normal, community-dwelling older adults without HIV that speed of processing is important to perform instrumental activities of daily living such as driving (Ball, Edwards, & Ross, 2007). Speed of Processing Training Unfortunately, despite recognized impairments in speed of processing in middle-aged and older adults with HIV, few studies have attempted to ameliorate this problem (Vance, Fazeli, Moneyham, Keltner, & Raper, in press). Fortunately, speed of processing training, a type of cognitive remediation therapy, has been shown to be effective in improving speed of processing in normal community-dwelling older adults, which transfers to everyday functioning, improved mood, and driving safety (Ball et al., 2007; Wolinsky et al., 2009). Based upon the principles of neuroplasticity, cognitive remediation therapies stimulate brains in a manner that builds new and stronger connections between neurons, from which cognitive abilities are improved (Vance & Wright, 2009). Typical cognitive remediation therapies consist of several sessions of computerized exercises administer over a period of time. These remediation therapies are specifically designed to extend one's cognitive abilities in a certain domain through repetitive exercise and instruction. In general, speed of processing training, consists of presenting visually complex information to participants and having them interact in a prescribed manner to such rapidly presented stimuli and providing them direct and timely feedback. Recently, in a sample of 46 middle-aged and older adults with HIV, Vance, Fazeli, Ross, Wadley, and Ball (in press) randomized participants into one of two groups: 1) speed of processing training, or 2) no-contact control. These researchers examined whether speed of processing training enhanced the participants' cognitive abilities and whether such improvements in speed of processing also transferred to a laboratory measure of everyday functioning called the Timed Instrumental Activities of Daily Living (TIADL) Test. This test is a timed measure consisting of various activities such as finding food items on a shelf of food, locating a telephone number in a phone book, and so forth. This measure and other cognitive measures were administered at baseline and approximately 4-6 weeks later, immediately after the speed of processing training was completed, in a typical two-group pre-post experimental design. The speed of processing training was self-administered using the INSIGHT™ computer program that utilized five different games or exercises (i.e., Bird Safari, Jewel Diver, Road Tour, Sweep Seeker, and Master Gardener) that were specifically designed to increase the participants' visual speed of processing (see Method for more detail). All of the games operated by either increasing difficulty if participants answered correctly or decreasing difficulty if participants answered incorrectly (i.e., double-staircase method). This method is thought to promote positive neuroplasticty in the brain with the goal of increasing the participants' visual speed of processing. As a result, Vance and colleagues found that participants in the speed of processing group significantly improved their visual speed of processing translating to improvements in the TIADL compared to those in the no-contact control group. From this study, it is encouraging to find that speed of processing training may be effective in improving cognitive and everyday functioning in adults with HIV. Purpose Although the benefits of this cognitive remediation therapy are promising in this clinical population, many predictors are known to impact cognitive functioning in adults with HIV (e.g., age, educational level, income, substance use, and co-morbidities; Vance, Fazeli, Moneyham et al., in press) that may result in differential training gains from this speed of processing training. Thus, the primary purpose of this secondary data analysis was to identify predictors of speed of processing training gains in those who received speed of processing training as seen in the previous study (Vance, Fazeli, Ross et al., in press). Secondary aims also included analysis of: (1) participants' reports of what was enjoyable about this intervention, and (2) the relationship between self-reported attitudes towards training and cognitive gains. This information can be used by nurses, nurse clinicians, nurse practitioners, occupational therapists, and psychologists to improve delivery of such cognitive remediation therapies in other venues (i.e., clinics, adult daycare centers).