Cognitive Ability and Performance in Adults with HIV

Abstract and Introduction

Although adults with HIV are at risk of developing cognitive impairments, the literature suggests that nurses and clinicians should be cautious about relying on patients' perceptions of their mental abilities. However, these findings are based on a questionnaire of cognitive complaints that may not lend itself easily to a clinical setting. In this pilot study, the relationship between a single item of self-reported cognitive ability and a global cognitive performance composite based on 7 neuropsychological tests was examined in 50 adults with HIV. Depressive symptomatology predicted lower self-reported cognitive ability; however, lower self-reported cognitive ability was also related to poorer cognitive performance but to a lesser extent. These results suggest that adults with HIV who report their cognitive ability as being poor may be experiencing depression, but they may also be experiencing declines in cognitive performance. These findings also suggest that a single item of self-reported cognitive ability may have some clinical value in detecting problems with global cognitive performance, as well as depression. Interventions for assessing patients and improving mood or cognition can be considered by nursing professionals treating individuals with HIV who report their cognitive ability as poor.

In clinical settings, it is common to rely on patients' self-reports of physical and mental complaints. Although such self-reports can be accompanied by standardized or validated instruments, often due to time constraints, patient demands, measurement costs, and scoring and interpretation issues of such instruments, these singular and unstructured self-reports are often taken at face value. This reliance does not necessarily mean that such self-reports are invalid; in fact, Knapp and Brown (1995) suggested that in many cases a single self-reported item may be quite appropriate for research and clinical purposes, such as assessing basic global status of certain domains. Clinically, it is intuitive to rely on patients' self-reports of phenomenological experiences such as pain, global health status, or fatigue (Wells, 1994). In fact, Crane and colleagues (2006) developed a single-item measure of health-related quality of life for HIV patients in clinical settings and found it to be just as sensitive to health-related outcomes as a standardized 21-item instrument. Likewise, a similar item may be relevant for assessing global cognitive ability in the HIV population.

HIV affects not only the immune system but also the nervous system, resulting in cognitive sequelae (Williams & Hickey, 2002). Bornstein and colleagues (1993) found cognitive declines in a sample of HIV-positive adults even after 1 year, but those participants with initially poor performance at baseline were more likely to experience such declines. Basso and Bornstein (2000) also observed cognitive declines after 1 year; however, premorbid intelligence mediated declines in neuropsychological function. Therefore, it is important to monitor cognition in this population, especially as this population ages and may be at particular risk of developing cognitive impairments because of HIV, aging, medication side effects, or a combination thereof (Vance & Robinson, 2004). Self-reported cognitive ability by patients may be a clinically justifiable method of monitoring cognition in this population.

Self-reported cognitive ability refers to how well a person thinks he or she is thinking (i.e., metacognition). If such self-reports are accurate, patients can detect problems in their thinking that may facilitate compensation, correction, or medical intervention. Nurses, clinicians, occupational therapists, and other health professionals instinctively rely on patients' self-reported cognitive ability to implicitly infer their cognitive performance. If patients do not self-report declines in cognitive ability (i.e., cognitive complaints), then it is assumed that there are no problems with thinking and that cognitive performance is within normal parameters for that individual.

In the HIV population, dependence on such self-reported cognitive ability is questionable. In several HIV studies, inconsistent correspondence between self-reported cognitive ability and actual cognitive performance has been found (Bassel, Rourke, Halman, & Smith, 2002; Moore et al., 1998; van Gorp et al., 1991). This suggests that the virus, or perhaps the antiretroviral medications, or even other unknown variables (Lang, Halleguen, Picard, Lang, & Danion, 2001), negatively impact the ability to monitor and accurately self-report on their cognitive performance.

Several studies have investigated this phenomenon. In 46 adults with HIV, Hinkin and colleagues (1996) found close to half of the sample self-reported their cognitive ability as being poor. However, such self-reported cognitive ability did not consistently correspond to actual cognitive performance (e.g., Wechsler Memory Scale—Revised and the California Verbal Learning Test). In fact, these researchers isolated three groups in their sample: (1) those whose self-reported cognitive ability was higher compared to their actual cognitive performance (26%), (2) those whose self-reported cognitive ability was lower compared to their actual cognitive performance (37%), and (3) those whose self-reported cognitive ability corresponded to their actual cognitive performance (37%). From this finding, approximately two-thirds of adults with HIV have significant difficulty self-reporting their cognitive ability as matched to their actual cognitive performance.

In addition, other researchers have shown that those who self-reported poor cognitive ability were more likely to have more negative affect. In a sample of 233 asymptomatic adults with HIV, van Gorp and colleagues (1991) found an association between self-reported cognitive ability and negative affect; however, a relationship between self-reported cognitive ability and cognitive performance was not found. Thus, those who self-reported their cognitive ability as being good were more likely to have higher positive affect even though such self-report was not reflective of actual cognitive performance. Similarly, in a sample of 92 symptomatic adults with HIV, Moore et al. (1998) found those with more negative affect also self-reported poorer cognitive ability. Again, a relationship between self-reported cognitive ability and cognitive performance was not found, thus illustrating that adults with HIV may have trouble accurately self-rating their cognitive ability.

Furthermore, in a sample of 36 adults with HIV, Bassel et al. (2002) found that only working memory performance and depressive symptomatology were related to self-rated cognitive ability. Interestingly, these researchers found that working memory and depression scores explained approximately the same amount of variance in self-rated cognitive ability. This suggests that in some cases, besides depressive symptomatology, self-rated cognitive ability may actually correspond to actual cognitive performance.

These studies have three things in common. First, two of these studies were conducted before the introduction of highly active antiretroviral therapy (HAART) in 1996 and 1997 (Palella et al., 1998). HAART has been documented to improve cortical and subcortical functioning in adults with HIV (Vance, 2004). In fact, the correspondence between self-reported cognitive ability and actual cognitive performance has been observed after HAART. For example, Bassel et al. (2002) found that those who self-reported their cognitive ability as being poorer were more likely to exhibit memory problems. Other studies that were conducted prior to the advent of HAART did not find such correspondence between self-reported cognitive ability and cognitive performance. This indicates that knowledge concerning this topic must be reevaluated.

Second, given the cognitive changes found during the aging process and the increasing number of older persons with HIV, the interaction of normal cognitive aging and the HIV disease process needs to be evaluated. Although the age of the participant was often used in these studies, samples were still rather young. Now, with an increasing number of older adults with HIV, age is an important consideration, especially when considering the potential synergistic effects that aging with HIV may have on cognitive functioning (Vance & Robinson, 2004). Current convention categorizes those who are 50 years of age or more with HIV as older (Stoff, Khalsa, Monjan, & Portegies, 2004). Using this rubric, in 2004 approximately 23% of adults with HIV in the United States were older (Gebo, 2006). Thus, studies are needed that include older adults who may be at risk for poorer cognitive performance as well as problems with self-reporting cognitive ability.

Third, a standardized measure of cognitive complaints was used in these studies (i.e., Cognitive Failures Questionnaire; Broadbent, Cooper, Fitzgerald, & Parkes, 1982). In previous studies, this measure of cognitive complaints has been used to predict individual domains of cognitive performance (e.g., perception, memory, and motor function); however, the total score of overall cognitive functioning from this questionnaire was used. This may explain why a global self-report questionnaire on cognitive failure has not been shown to predict performance on individual domains of cognitive functioning. However, a self-report of global cognitive ability may be found to predict global cognitive performance.

Furthermore, an overall rating of self-reported cognitive ability is more likely to be used in routine clinical care than a formalized measure of self-reported cognitive ability. Although a validated instrument such as this is an asset in research protocols, it may not be practical or ecologically valid to administer in a clinical setting given that it takes approximately 10 minutes to complete (Broadbent et al., 1982). By analogy, self-reported health, a single-item measure, has been shown to be predictive of overall physical health and mortality (Chandola & Jenkinson, 2000; Manderbacka, Kareholt, Martikainen, & Lundberg, 2003). Therefore, a simple self-report of overall cognitive ability may also be predictive of global cognitive performance of the patient.

The primary purpose of this study was to examine the relationship between self-reported cognitive ability, global cognitive performance, and depressive symptomatology in a sample of adults with HIV using data from a previous study (Vance, Woodley, & Burrage, 2007). The secondary purpose of this study will determine if a simple, single item of self-reported cognitive ability corresponds to an overall global composite of cognitive performance as well as depressive symptomatology. Pooling neuropsychological measures together to form a global composite of cognitive performance may strengthen the ability to detect whether a single-item self-reported cognitive ability measure is clinically useful and valid in adults with HIV.

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