Carlton S. Gass

MMPI profiles of closed head trauma patients: Impact of neurologic complaints

The MMPI is used commonly with neurologic patients despite concerns about its validity with this population. The basis for this concern--possible artifactual effects due to neurologic-related MMPI items (NRIs)--was assessed in this study of 58 closed head trauma (CHT) patients. The MMPI profiles of these patients were analyzed before and after statistical correction was made for 42 NRIs that were identified by three neurologists. Significant effects occurred on Scales 1 (HS), 2 (D), 3 (HY), 7 (PT), and 8 (SC) in regard to their T scores, frequency of pathological elevation (T greater than 69), and representation in configural codes. The results suggest that MMPI content scales and subscales may help to distinguish the relative contribution of neurologic and emotional complaints on MMPI profiles.

Emotional Impact on Trail Making Test Performance

This study assessed the effect of emotional factors on Trail Making Test Part B performance for a sample of 105 neuropsychological referrals for whom there was no neurodiagnostic evidence of brain damage. Trails B scores declined in relation to elevated MMPI scores on Scales 6, 7, and 8, though only nine patients performed within the impaired range. The results suggest that (a) Trails B performance is resilient to a variety of emotional influences, (b) psychotic symptoms and severe anxiety impede Trails B performance, though rarely to the extent caused by brain damage, and (c) the MMPI provides objective criteria that help rule out emotional effects on Trails B performance.

Emotional variables and neuropsychological test performance

Although previous studies have demonstrated the general success of neuropsychological tests in discriminating brain-impaired patients from normals and patients with psychiatric disorders, limited attention has addressed the more specific effects of emotional disturbance on test performance. This study investigated MMPI correlates of Halstead-Reitan test (HRB) performance in a sample of 105 neuropsychological referrals (predominantly psychiatric) who had negative neurologic findings. The results indicated significant effects for age and education on many of the tests, with smaller but statistically significant relationships between the quality of HRB test performance and MMPI scores.

Emotional correlates of fluency test and Maze performance

This study tested the hypothesis that depression, anxiety, and bizarre thought content, as measured by MMPI-2 scales, would show a negative relationship with performance on widely used measures of executive functioning. Subjects were 70 male psychiatric patients who were ostensibly free of any neurologic disease or history of substance abuse. Correlational analyses were performed between age and education-corrected scores on the Controlled Oral Word Association Test (FAS), Design Fluency, and WISC-R Mazes, and scores on MMPI-2 scales D, PT, Anxiety, Fears, Obsessional Thinking, Depression, and Bizarre Mentation. The findings suggest that fluency and maze performance is (1) largely independent of measures of depression (D, DEP) and bizarre mentation (BIZ); (2) mildly associated with a measure of generalized anxiety (ANX); and (3) strongly related to an MMPI-2 measure of fearfulness (FRS).

MMPI-2 indices of psychological disturbance and attention and memory test performance in head injury

A number of studies have investigated the relationship between psychological disturbance and neuropsychological (NP) test performance. The current study is a replication and extension of who found that MMPI-2 indices of psychological disturbance are related to performance on NP tests of attention and memory in psychiatric and head-injured patients. In a large sample (N=381) referred for evaluation after sustaining presumed head injury, we examined the relationship between MMPI-2 indices of psychological disturbance and measures of attention and memory from the Wechsler Memory Scale-Revised (WMS-R), Wechsler Adult Intelligence Scale-Revised (WAIS-R), California Verbal Learning Test (CVLT), and the Memory Assessment Scales (MAS). Although related to other domains, MMPI-2 variables were most consistently related to measures of attention and List Learning. Even when demographic variables, injury severity, and litigation status were controlled, MMPI-2 indices significantly predicted performance on six out of eight tests. However, the correspondence between similar indices on the WMS-R and MAS were relatively low, especially for Verbal Memory and Visual Reproduction. Further, litigation was significant in predicting only 2 of 8 attention and memory indices.

MMPI-2 SCALE F(þ) and Symptom Feigning: Scale Refinement

The F(l=thorn) scale of the MMPI-2 is widely used to help identify exaggeration of psychological problems in psychiatric, forensic, and neuropsychological settings. The scale was constructed by selecting all MMPI-2 items (N = 27) that were endorsed by less than 20% of a sample of VA psychiatric inpatients and 20% of the normative sample used in restandardizing the MMPI-2. Although þ is used to measure symptom exaggeration and malingering, 4 of its 27 items load on the Lie (L) scale, which is known to be a measure of defensiveness and symptom underreporting. These four items, which express a denial of occasional anger, irritability, and procrastination, could conceivably measure an uncommon expression of defensiveness. This study used 150 neuropsychological referrals to test the hypotheses that (a) the four L scale items measure defensiveness, not exaggeration, and (b) the elimination of these items improves the utility of þ in assessing symptom exaggeration. The results indicate that the four L scale items are associated with defensiveness, not with symptom exaggeration. One third of the patients had an average T-score artifact of 9.5 points on þ as a result of endorsing these L scale items, with a range of OT to 21 T. Using the K scale as a criterion for level of problem disclosure, a shortened version of þ (omitting the four L scale items) was superior to þ as a measure of symptom exaggeration (r= -.46 vs. -.36, r2 = 21% vs. 13% of the variance). The implications for clinical practice are discussed.

MMPI correlates of verbal-intellectual deficits in patients with left hemisphere lesions

This study investigated the emotional adjustment of patients (N = 31) with left hemisphere damage (LHD) as a function of the degree of impairment in verbal intelligence as measured by the Wechsler Adult Intelligence Scale. A multivariate comparison was made of the composite MMPI profiles of three groups of LHD patients classified according to Verbal IQ. The three groups produced fairly similar composite profiles, which indicated the presence of mild dysphoria, dissatisfaction, withdrawal, decreased initiative, and mild somatic preoccupations. Significant correlations emerged between the degree of verbal-intellectual disability and MMPI F, PT, SC, and SI. However, when the variance in MMPI scores due to premorbid status (education) was partialled out, these correlations dropped to nonsignificant levels. These findings failed to support previous studies that linked verbal deficits with emotional disturbance, and they underscore the importance of premorbid intelligence in the psychological adjustment to organic impairment.

Interpretation of VIQ-PIQ and Intersubtest Differences on the Spanish Version of the WAIS (EIWA):

Although the Spanish version of the Wechsler Adult Intelligence Scale (WAIS; Escala de Inteligencia Wechsler para Adultos [EIWA]) is the most frequently used intellectual assessment for Spanish speaking clients in the United States, there is little information available on score differences necessary to establish reliable and abnormal differences between Performance IQ (PIQ) and Verbal IQ (VIQ), and between the various subtests of the EIWA. The present study, based on EIWA standardization data (N = 616 Puerto Ricans), reports reliability data and base rates to assist in evaluating the clinical significance of PIQ-VIQ differences. The results demonstrated substantial similarity between the EIWA and the English versions of the Wechsler tests. The interpretation of these differences is discussed, and tables are presented of statistically and clinically significant differences.

MMPI‐2 interpretation and stroke: Cross‐validation of a correction factor

Accumulating data indicate that the MMPI-2 contains items that may be sensitive to neurologic conditions independent of a patients psychological status. Gass (1992) identified 21 stroke-related MMPI/MMPI-2 items which were recommended for use as a score-correction index. This study examined these items using a cross-validation sample of 50 VA stroke patients. Item endorsement rates were contrasted with those of the MMPI-2 normative sample. The following results were obtained: The MMPI-2 items that distinguished stroke patients from normals have neurologic symptom content, all 21 correction items were upheld as effective discriminators, and the 21 items were commonly endorsed by the CVA patients (mean = 52%, range: 22% to 75%). These findings support the composition of the MMPI-2 correction for stroke and the rationale on which its application is based.

MMPI correlates of Performance intellectual deficits in patients with right hemisphere lesions

This study investigated the emotional adjustment of 50 patients with focal brain damage in the right hemisphere (RHD). The impact of functional loss (as assessed by the WAIS Performance IQ) was assessed by a multivariate comparison of the composite MMPI profiles of these patients as classified into three groups: Below Average, Average, and Above Average Performance IQ. Regardless of the extent of decline in Performance-related abilities, right hemisphere impairment was associated with symptoms of mild depression, loss of initiative, anxiety, denial, and somatic preoccupations. MMPI scores were not correlated significantly with their WAIS Performance IQs. Implications for neuropsychological assessment are discussed.