Mark A. Williams

The relationship between cardiac function and neuropsychological status among heart transplant candidates

BACKGROUND Cognitive deficits among heart transplant candidates have been well documented. This study was designed to examine the hypothesis that impaired cognitive test performance among heart transplant candidates may be attributed, in part, to decreased cerebral perfusion secondary to poor cardiac function. METHODS AND RESULTS Sixty-two patients participated in the study who underwent heart catheterization within 1 day of completing a battery of cognitive tests. Multiple demographic and patient characteristics were examined for their potential moderating role in the relationship between measures of cardiac function and cognitive performance including age, education, race, gender, psychiatric history, medication usage, cardiac surgical history, and self-reported symptoms of depression and anxiety. Only age and education were significantly related to cognitive performance (P < .01). Thus, partial correlation analyses controlling for age and education were used to examine the relationship between cardiac function and cognitive performance. In general, increasing hemodynamic pressure variables (ie, pulmonary artery pressure and right atrial pressure), and to a lesser extent cardiac output and cardiac index, were related (r = - .32 to - .43; P < .01) to decreased performance on cognitive tasks that assessed simple attention, speed of mental processing, and mental flexibility (Digit Span-Forward, Trail Making Test-Part B, Symbol Digits Modalities Test, and Stroop Neuropsychological Screening Test). Left ventricular ejection fraction, systemic and pulmonary vascular resistance, and mean arterial pressure were largely unrelated to cognitive performance in this sample of patients with end stage cardiac disease. CONCLUSIONS Hemodynamic pressure variables seem to be most consistently related (ie, inversely) to cognitive functioning among heart transplant candidates.

Heart Transplant Candidates: A Neuropsychological Descriptive Database

Clinical psychologists working in medical settings are increasingly broadening their services to include consultation to cardiac transplant programs. These services may include the neuropsychological assessment of end-stage cardiac patients, who as a group are at risk for neuropsychological impairment. This paper provides descriptive neuropsychological data partitioned by age, race, and educational level from a sample of 760 end-stage cardiac patients who underwent neuropsychological testing as a routine part of a comprehensive heart transplant candidacy evaluation. Between one-fourth and one-third of the sample obtained scores that fell two standard deviations or greater below the expected performance (using available norms) on 11 of the 19 test variables. Performance difficulties were most commonly found on tests of manual speed, psychomotor speed, mental speed, and verbal learning and memory. This descriptive report improves upon previously published papers that were limited by relatively small sample size and failure to partition test results across important demographic characteristics.

Activities of daily living among heart transplant candidates: neuropsychological and cardiac function predictors

BACKGROUND The ability of patients to perform day-to-day tasks (e.g., medication management, dietary regulation) is an important concern of transplant teams. METHODS We studied a clinical series of 75 heart transplant candidates and 38 controls to examine the predictive validity of demographic, neuropsychologic, and cardiac function variables to a performance-based measure of instrumental activities of daily living (IADL) capacity (i.e., Everyday Problems Test, EPT). RESULTS Multiple regression analyses, controlling for education and race, indicated that neuropsychologic tests accounted for between 34% and 67% of the variance across IADL domains (e.g., cooking, household chores, medication management). The IADL capacity was most consistently predicted by long-standing verbal ability (Shipley Institute of Living Scale-Vocabulary, SILS-VOC) and psychomotor speed and mental flexibility (Trail Making Test-Part B, TMT-B). Similarly, SILS-VOC and TMT-B also tended to show the best operating characteristics (i.e., sensitivity, specificity, positive predictive power, negative predictive power) for detection of dependence across IADL domains. In contrast, cardiac function measures (e.g., cardiac output, mean atrial pressure) were largely unrelated to the patients performance on the paper-and-pencil EPT task. CONCLUSIONS Long-standing intellectual ability, and a measure of speeded information processing and mental flexibility are the best predictors of IADL capacity.

Neurocognitive and Emotional Functioning in Lung Transplant Candidates: A Preliminary Study

This study reports descriptive data on the neurocognitive and emotional functioning of a clinical series of 39 lung transplant candidates. Results found this group to be of average intelligence, with average simple attention and concentration. Candidates displayed mild to moderate psychomotor slowing, moderate dysnomia, and mild verbal memory and learning deficits. Relative to available normative data, 39% of the patients demonstrated performance deficits at or below three standard deviations from the mean on two or more neurocognitive test variables. Cluster analysis of MMPIs identified three groups: Cluster 1 consisted of 26% of the sample, with significant elevations on scales 1, 2, 3, 4, 7, and 8 suggestive of clinically significant levels of emotional distress; Cluster 2 consisted of 39% of the sample, with significant elevations on scales 1, 2, and 3 suggestive of moderate somatic concerns and mild emotional disruption; Cluster 3 consisted of 35% of the sample, with no significant MMPI scale elevations. Nearly one-third of the sample obtained MMPI F-K scores suggestive of a “fake-good” response set. Neurocognitive test performance and MMPI scales were only minimally related, suggesting that emotional disruption cannot be used as an explanation for neurocognitive deficits in this sample.

The Impact of a Defensive Response Set on the Relationship Between MMPI and Cognitive Tests Among Heart Transplant Candidates

Examination of the relationship between self-reported psychological symptoms (e.g., depression and anxiety) and cognitive tests assumes individuals are highly motivated to both openly disclose psychological symptoms and to extend best-effort on cognitive tests. Situations that change this ideal motivational state on either self-report questionnaires or cognitive tests attenuate the validity of this assumption. To illustrate this problem, this study examined the emotional-cognitive correlation in a clinical series of 136 cardiac patients undergoing psychosocial and cognitive evaluation as part of a standard protocol for entry into a cardiac transplant program. The evaluative nature of the psychosocial assessment motivates some candidates to respond in a defensive manner, thereby decreasing the validity of self-report psychological measures. This same situation likely promotes high performance motivation on cognitive tests. It was hypothesized that a defensive response set on the Minnesota Multiphasic Personality Inventory (MMPI), as measured by the F-K (Frequency-Correction) Gough Dissimulation Index, would attenuate the strength of the emotional-cognitive relationship. Cognitive factor scores were generated and correlated with the MMPI state clinical scales (i.e., scales 2, 7, and 8) for both nondefensive and defensive (F-K ≥ −15) groups. Results show increased emotional distress was reliably associated with decreased cognitive functioning (rs = −.22 to −.27) among the nondefensive group, but was unrelated in the defensive group. The importance of considering the influence of performance contingencies within research and clinical settings is discussed.

Self-Report Versus Performance-Based Activities of Daily Living Capacity Among Heart Transplant Candidates and Their Caregivers

Transplant candidates completed the Every Day Problems test (EPT), a performance-based measure of instrumental activities of daily living (IADL), and the Katz self-report scale of IADL functioning. Caregivers estimated the candidates IADL capacity using the Katz scale. A healthy community group and patients with cardiac disease not undergoing transplant evaluation and their caregivers served as controls. Discrepancies between the EPT and Katz scales were generated. Results showed that the total number of discrepancies was significantly higher among the two patient groups as compared to controls. Three or more discrepancies (a total of 7 IADL domains were assessed) occurred in 40–52% of the participants and their caregivers in the two patient groups. Similarly, the total number of discrepancies between the Katz scale of the participant and their caregiver was significantly higher among the two patient groups as compared to controls, with only 33–44% showing perfect agreement in the patient groups as compared to 97% among controls. Despite a high prevalence of discrepancies in both patient groups, results did not support the hypothesis that transplant candidates tend systematically to overestimate their ability level on self-report IADL measures.

Visual reproduction subtest of the Wechsler Memory Scale-Revised: Analysis of construct validity

This study assessed the construct validity of Visual Reproduction (VR) Cards A (Flags) and B (Boxes) from the original Wechsler Memory Scale (WMS) compared to Flags and Boxes from the revised edition of the WMS (WMS-R). Independent raters scored Flags and Boxes using both the original and revised scoring criteria and correlations were obtained with age, education, IQ, and four separate criterion memory measures. Results show that for Flags, there is a tendency for the revised scoring criteria to produce improved construct validity. For Boxes, however, there was a trend in the opposite direction, with the revised scoring criteria demonstrating worse construct validity. Factor analysis suggests that Flags are a more distinct measure of visual memory, whereas Boxes are more complex and significantly associated with conceptual reasoning abilities. Using the revised scoring criteria, Boxes were found to be more strongly related to IQ than Flags. This difference was not found using the original scoring criteria.

Serial 7s and Alphabet Backwards as brief measures of information processing speed

The construct and discrimant validity of Serial 7s and Alphabet Backwards as measures of information processing speed were examined. In Study 1, seven commonly used speeded neuropsychological measures, including Serial 7s and Alphabet Backwards, were subjected to factor analysis. Two factors emerged. Factor 1 was labeled visual-motor scanning speed. Factor 2 was labeled information processing speed and included Serial 7s and Alphabet Backwards. Study 2 compared 42 cardiac transplant candidates and 46 age, education, and IQ matched college student controls on Serial 7s and Alphabet Backwards. The cardiac patients were significantly slower on both Serial 7s and Alphabet Backwards but did not make more errors. These results suggest that Serial 7s and Alphabet Backwards can be used as brief and technically simple measures of information processing speed.

Psychological Defensiveness Among Heart Transplant Candidates

This study examined the utility of the K-correction procedure (i.e., raw score weights added to scales 1, 4, 7, 8, 9) to adjust for a defensive response set on the MMPI. The sample consisted of 51 patients with end-stage heart disease undergoing psychosocial evaluation for transplantation. Participants were separated into “defensive” and “nondefensive” groups using a median split on the K scale (defensive defined as T-score ≥ 59). The MMPI was scored once in the standard manner and then rescored omitting all K-scale items from the clinical scales. As hypothesized, raw score analysis after omitting K-scale items showed the defensive group endorsed significantly fewer items on three of the five clinical scales involving K-correction (scales 1, 7, 8). In contrast, analysis of K-corrected T-scores using standard procedures showed a significant group difference only on scale 4, with a higher T-score found among the defensive group. The defensive and nondefensive groups were not significantly different on numerous demographic, medical, and psychiatric characteristics, suggesting that the tendency to respond in a defensive manner is the major characteristic that distinguishes the two groups. Given this assumption, the K-correction procedure appears to appropriately adjust for a defensive response set on scales 1, 7, 8, and 9, whereas K-correction may overadjust on scale 4.

A DEFENSIVE RESPONSE SET AND THE RELATION BETWEEN COGNITIVE AND EMOTIONAL FUNCTIONING : A REPLICATION

This study was designed to examine the hypothesis that a defensive self-report response set tends to attenuate the strength of the relationship between self-reported emotional functioning and cognitive tests, particularly the functioning of verbal memory. 75 patients with end-stage lung disease were administered the MMPI and a cognitive test battery as part of a psychosocial evaluation for transplantation. Patients were separated into defensive and nondefensive groups using the MMPI F – K Gough Dissimulation index (raw score F minus K⩽−15). Cognitive factor scores were generated and correlated with non-K-corrected raw scores of MMPI Scales 2, 7, and 8. Correlation coefficients were compared across groups. As predicted, increases on Scales 2 and 7 were significantly associated with decreased functioning of verbal memory (r = −.35 and −.34, respectively) among the nondefensive group but were unrelated in the defensive group. It is argued that the attenuation of the relationship between self-reported emotional status and verbal memory functioning is, in part, due to a restricted range of symptom endorsement on the MMPI among the defensive group. These findings replicate those previously reported using a sample of patients with cardiac disease.