This study tested the effects of neurocognitive functioning, reading literacy for health-related information and numeracy on the ability to manage a simulated HIV medication regimen. Although studies have found each of these skill areas to be related to medication management, no study to date has evaluated how these skills may relate to one another and to understanding medication instruction. Our findings showed that tests of reading comprehension and mathematical reasoning shared common traits with neuropsychological measures that require working memory, mental flexibility, visual scanning, and organization. This set of executive skills was highly associated with successfully managing the simulated HIV regimen. Similarly, planning skills were demonstrated to be important for completion of this task as well. A number of studies have shown impairment in cognitive function and executive skill in particular to affect medication adherence in individuals with HIV infection.12,43,44
Executive function is a broad term that encompasses a number of higher order skills necessary for independent, goal-directed behavior, including holding and manipulating information in working memory, planning/sequencing multistep tasks, and ascertaining the “big picture” from a complicated set of details.45
Recent studies have emerged to describe the contribution of executive skill to reading comprehension.46,47
Although deficits in single-word decoding, fluency, and reading proficiency explain a portion of reading comprehension deficits, they do not account for all problems with reading comprehension and for those whose single word reading is intact. Studies have shown that children with dyslexia display working memory deficits in both verbal and visual domains.48
Verbal working memory has been linked to reading comprehension across a number of studies49–51
and is thought to “…
facilitate comprehension through the availability of ample cognitive resources to simultaneously engage in multiple reading processes including decoding of unfamiliar words, retrieving semantic knowledge of familiar words, recalling previously read text, and anticipating where the passage is going.”47
Moreover, reasoning and critical analysis are also thought to influence reading comprehension52
and those with good reading comprehension are more likely to use cognitive and metacognitive strategies.53
On measures requiring an organized response, children with reading comprehension difficulties tend to produce less organized and less structured copies of geometric figures (similar to the Rey Complex Figure task used in the present study) and require longer planning times on visual problem solving tasks.48,54
Sesma et al.47
demonstrated that executive skills (measured by the Tower of London, and Arithmetic and Digit Span tests that are working memory components of the Wechsler Intelligence Scale for Children) were associated with reading comprehension but not single word recognition in children. Arithmetic measures that require computation and inference of mathematical operands are also strongly associated with attention and working memory. The arithmetic subtest from the Wechsler Intelligence Scales55
contains similar task demands to those of the Applied Problems test used in the present study, with the exception that scoring is based partially on speed of response. In a factor analysis, the arithmetic test loads on an IQ index termed “Freedom from Distractibility” tapping attention, working memory, and organizing skill sets.56
This evidence lends support to the present study showing that executive skills are inherently involved in reading comprehension and numeracy. Although planning skill did not load on the same factor as the literacy, numeracy and other executive skills, its association with medication management as well suggests that it too is an important, higher order cognitive process that is necessary to carry out rather complex day-to-day health behaviors such as medication management. In the context of earlier research, a number of studies found the TOFHLA and other reading tests (e.g., the REALM) to be related to medication understanding and adherence.15–20
Moreover, interventions stemming from such findings have used nonwritten communication strategies such as pictorial medication cards, to communicate medication instructions.19
Although these interventions have met with some success, the findings presented herein suggest that successful medication management for low health literate individuals involves a broader and more complex array of skills than only reading ability.
A recent study found HIV perinatally infected adolescents to have significantly lower receptive language and word recognition skills than those who were perinatally exposed to HIV but did not seroconvert. Moreover, their performance was well below that of age appropriate expectations. Unfortunately, executive skill was not assessed in this study and so the contribution of executive deficits to language deficiencies cannot be measured. The findings emphasize that HIV may have a significant effect on language skill that should be accounted for in care programs for this population.57
The generalizability of this study is limited since the study sample was not randomly selected and was comprised mostly of African Americans. However, executive and planning skills are a universal human ability that would be equally important to those who confront the task of medication management regardless of background, level of education, or nationality. Second, contemporary HIV regimens often contain fewer total medicines than the five used in our simulated regimen. This may decrease generalizability for less complex regimens which are associated with poorer management.40
However, in addition to antiretroviral medicines, many HIV patients are also prescribed prophylactic medications, vitamins, and supplements that also require adequate adherence for maximum effectiveness. Therefore, we believe these findings to still be relevant for many HIV-positive patients. It also noteworthy to consider the present findings within the parameters of health numeracy put forth by Ancker and Kaufman.26
They purport that productive use of quantitative health information, such as completion of a medication regimen, depends in part on the health numeracy abilities of the individual. It also depends on the ability of the communication device, whether through an individual expert or information artifact, to effectively communicate clear, “cognitively manageable” information.26
Poorly communicated information can handicap even those with advanced numeracy skill whereas effectively communicated health information can help to compensate for weak individual skill. The findings from the present study constitute only a portion of the dynamic of functional health literacy by measuring individual-level ability. A number of other factors untested in the present study may also impact self-management of one's medications such as drug use,12
support of family or caregivers,41
and self-efficacy for medication taking.42
Nonetheless, these findings help to underscore individual skill sets of particular relevance for managing medications.
The optimal point of intervention based on these findings, whether with the individual, provider, healthcare system, or some combination thereof, should be evaluated in further intervention research.
These findings hopefully increase provider awareness of the complexity of higher order cognitive processes on which patients must rely to successfully navigate medication self-management. Although reading and arithmetic are key elements for understanding prescription instructions, they are carried out via metacognitive processes that may be more challenging to identify. In diseases such as HIV/AIDS that produce cognitive dysfunction, the need to assess for cognitive dysfunction as well as reading and numeric literacy is further illustrated here. Based on these findings, efforts to simplify health information that merely lowers readability are likely to meet with limited success.