Longitudinal and psychometric profiles of two cognitive status tests in very old adults.

Forty-four nondemented adults, over the age of 75 years, were tested at six-month intervals spanning two years. Study goals were to examine the validity of the Mini-Mental State Examination (MMSE) and the Wechsler Adult Intelligence Scale-Revised (WAIS-R), to assess the long-term reliability of these instruments, and to examine the longitudinal profile of this sample. Results showed that the MMSE was moderately correlated with the WAIS-R. The MMSE had low internal consistency, although the total score behaved reliably across the five occasions. The WAIS-R scales showed a high degree of internal consistency and test-retest reliability. WAIS-R performance remained stable across occasions; however, decline was evident in the MMSE subtests of Attention and Language.

Victoria Symptom Validity Test: efficiency for detecting feigned memory impairment and relationship to neuropsychological tests and MMPI-2 validity scales.

Error scores and response times from a computer-administered, forced-choice recognition test of symptom validity were evaluated for efficiency in detecting feigned memory deficits. Participants included controls (n = 95), experimental malingerers (n = 43), compensation-seeking patients (n = 206), and patients not seeking financial compensation (n = 32). Adopting a three-level cut-score system that classified participant performance as malingered, questionable, or valid greatly improved sensitivity with relatively little impact on specificity. For error scores, convergent validity was found to be adequate and divergent validity was found to be excellent. Although response times showed promise for assisting in the detection of feigned impairment, divergent and convergent validity were weaker, suggesting somewhat less utility than error scores.

Effects of prior testing with the WAIS-R NI on subsequent retest with the WAIS-R.

Seven subtests from the Wechsler Adult Intelligence Scale, Revised as a Neuropsychological Instrument (WAIS-R NI) were administered to 20 nonreferred university students. The same participants were administered the corresponding subtests from the WAIS-R 3 to 4 weeks later. Data concerning amount and consistency of change in 'scaled scores' were compared to those reported by Wechsler (1981) for test-retest with the WAIS-R. Performance on standard items was also compared to performance on multiple choice items from the WAIS-R NI. Gains observed in subtest 'scaled scores' at retest were comparable to those reported by Wechsler (1981). A substantial minority of participants obtained lower scores on some multiple choice items than they did on corresponding standard items. Implications and limitations of the current data, and the pressing need for comprehensive normative data for the WAIS-R NI are discussed.

Detecting dissimulation: profiles of simulated malingerers, traumatic brain-injury patients, and normal controls on a revised version of Hiscock and Hiscock's Forced-Choice Memory Test.

A computer-administered memory test was given to normal subjects instructed to feign brain damage, normal controls, and traumatic brain-injured (TBI) patients with complaints of memory dysfunction. The test, a revised version of an instrument developed by Hiscock and Hiscock (1989) employed forced, two-choice recognition of previously presented five-digit numbers. Two levels of item difficulty and three retention intervals were used. Control and TBI subjects performed at near ceiling level on easy items and items with short retention intervals. Feigning subjects performed worse than TBI and control subjects at all levels of item difficulty and all retention intervals. Subjects groups were maximally distinguishable from one another by performance on difficult items and items with the longest retention interval. All TBI patients performed at or above chance level. Only 15% of the feigning subjects performed below chance level on any section of the test. Jack-knifed discriminant function analysis correctly classified 83% of all subjects into their respective groups. Although evaluation of patient performance relative to chance probability is useful for indicating the presence of extremely exaggerated memory deficits, criteria derived from sample distributions of group scores were superior for evaluation of motivation in less obvious cases. The Victoria Revision may be useful for detecting true memory deficit as well as dissimulation.

[Toxoplasmosis encephalitis in patients with AIDS]. / Toxoplasmose-Enzephalitis bei Patienten mit AIDS.

Toxoplasmosis encephalitis developed in three male homosexuals with AIDS. Clinical symptoms of encephalitis began with a nonspecific organic mental syndrome. In two cases there developed late focal symptoms. There were light to moderately severe generalized EEG changes with additional focal signs. CSF findings and toxoplasmosis titres were not diagnostically altered. Computed tomography demonstrated multiple areas of decreased density in cortex and cerebellum. Administration of pyrimethamine and sulfamethoxydiazine to the three patients brought about clinical improvement within a few days and regression of abnormal CT changes within a few weeks of onset of treatment. One patient died after an encephalitis recurrence: autopsy demonstrated toxoplasma pseudocysts in immediate proximity to small necrotic foci in the brain. The possibility of toxoplasma encephalitis should be considered in AIDS patients who develop an organic mental syndrome. Often the diagnosis can only be made after response to a trial of toxoplasmosis treatment.