Predicted performance experiments attempt to quantify an impaired individual's awareness of his or her deficit. These experiments measure perceived ability by the individual's prediction of his or her performance on a specific cognitive task and actual ability by his or her subsequent performance on that task. To date, the most comprehensive predicted performance experiment is the one proposed and implemented by McGlynn and Kaszniak (1991b). This experiment is potentially capable of removing a number of influences that may be confounded with deficit unawareness; however, it is not obvious what method of quantitative analysis best exploits this capability. In the present report, several possibilities are discussed. The limitations of McGlynn and Kaszniak's method are identified, and a more satisfying measure of deficit unawareness is proposed. (JINS, 1996, 2, 315–322.)

These studies provide evidence for slowed spatial orienting of attention in autism. A group of well-defined adult autistic subjects and age-matched normal controls performed a traditional spatial cueing task in which attention-related response facilitation is indexed by speed of target detection. To address the concern that motor impairment may interfere with interpretation of response time measures in those with neurologic abnormality, we also used a new adaptation of the traditional task that depended on accuracy of response (target discrimination) rather than speed of response. This design allowed separation of time to process and respond to target information from the time to move and engage (orient) attention. Results from both tasks were strikingly similar. Normal subjects oriented attention very quickly, and showed maximal performance facilitation at a cued location within 100 ms. Autistic subjects oriented attention much more slowly and showed increasing benefits of a spatial cue with increasing cue-to-target delays. These results are consistent with previous reports that patients with autism, the majority of whom have developmental abnormalities of the cerebellum, as well as those with acquired damage to the cerebellum, are slow to shift attention between and within modalities. This paper also addresses the variability in behavioral findings in autism, and suggests that many of the apparently contradictory findings may actually reflect sampling differences in patterns of brain pathology. (JINS, 1996, 2, 541–550.)

On the basis of what is known about the neural circuitry essential or normally involved in eyeblink classical conditioning (EBCC), the pattern of neurodegeneration in Huntington's disease (HD) would not appear to interfere with this type of learning. HD causes severe atrophy of the basal ganglia and thinning and shrinkage of the cerebral cortex. However, the hippocampus and hippocampal cholinergic system remain relatively intact, as does the cerebellum. Because the brain circuitry engaged in EBCC is neither lesioned nor disrupted in HD, it was predicted that HD patients would perform like normal control subjects in the 400-ms delay EBCC paradigm. Performance of seven patients with HD was compared to age-matched normals, with two control subjects matched to each HD patient. There were no differences in production of conditioned responses (CRs) between HD patients and normal control subjects, but the timing of the CR was abnormal in HD. Comparisons of HD patients to patients with other neurodegenerative diseases (probable Alzheimer's disease (PAD) and Down syndrome (DS) over the age of 35 with presumed Alzheimer-like neuropathology) and to patients with cerebellar lesions demonstrated significantly better EBCC performance in HD. Results suggest that the ability to acquire CRs is normal in HD, but the striatum may have some role in optimizing the timing of the CR. (JINS, 1996, 2, 323–334.)

There have been few studies of psychogenic amnesia based on a cognitive or neuropsychological framework. In the present study, a patient with acute onset of profound psychogenic retrograde amnesia was examined. Although her performance on neuropsychological tasks revealed intact anterograde memory, language functioning, visuospatial and constructional skills, and mental speed and flexibility, she displayed severe impairments on a variety of retrograde memory tasks. Furthermore, initial observations revealed inconsistencies between the patient’s recall of semantic knowledge on direct questioning and her ability to demonstrate the use of this knowledge on indirect tasks. To test this formally, we devised an indirect remote knowledge task to examine a possible dissociation between explicit and implicit memory. Two healthy subjects matched for age, gender, education, occupation, and estimated IQ were also tested. As predicted, the findings demonstrate implicit knowledge despite impaired explicit recall for the same material. (JINS, 1996, 2, 146–158.)

Eighty-five subjects at various stages of human immunodeficiency virus (HIV-1) infection and 39 seronegative controls underwent neurological and neuropsychological evaluation to assess the relationship between cognitive test results and subjective complaints (cognitive, affective, motor, and other). The effect of psychiatric disorders on the association between cognitive performance and complaints of the patients was also examined. Patients with symptomatic infection had higher frequency of complaints than subjects at asymptomatic stage. Detailed neuropsychological examination confirmed a strong association between poor verbal memory and cognitive complaints. Poor performance on cognitive speed and flexibility was associated with motor complaints and motor abnormalities. These associations were not explained by psychiatric disorders or elevated depression questionnaire scores. Our observations indicate that, especially in symptomatic HIV-1 infection, cognitive changes reported by patients often reflect “objective” cognitive decline, and may be the earliest signs of HIV-1 associated cognitive disorder. No direct relationship was observed between “subjective” complaints and neuropsychological performance of asymptomatic subjects. Understanding the significance of reported cognitive changes have important therapeutic implications. (JINS, 1996, 2, 219–225.)

In this paper different models of anosognosia are confronted and data concerning denial behaviors are presented that were collected on a selected population of right brain-damaged patients affected by motor and neglect disorders. Anosognosia for motor impairment and anosognosia for cognitive impairments were found to be dissociated, as well as anosognosia for the upper and lower limb motor impairments. These findings are then discussed in an attempt to choose the more suitable theoretical framework for interpreting the various disorders related to denial of illness. (JINS, 1996, 2, 426–440.)

A previous study of the performance of men with chronic unilateral focal brain lesions (due to wartime missile injury) on a standard test of line orientation suggested a left hemisphere (LH) as well as a right hemisphere (RH) contribution to visuospatial processing. The present study was designed to fractionate the variables that could underlie this unexpected finding and thereby to tease out the mechanisms involved in LH as compared with RH processing. A simpler (“purer”) version of the standard line orientation task was used, as were two other versions in which matching in an array and matching with distractors were measured. The findings confirmed the hypothesis of RH involvement in the purer task of metric measurement and suggested that the LH has an important role in keeping track of decisions and updating decisions in more complex aspects of line orientation judgment. (JINS, 1996, 2, 335–339.)

In the current study, we investigated whether standard assessment techniques of visuospatial neglect are sensitive to detecting dissociable subtypes. We administered a battery of tasks commonly used to detect the presence of visuospatial neglect to 120 patients with unilateral right hemisphere infarcts and, in most cases, performed a systematic analysis of their lesions to quantify and localize brain damage. Using a factor analysis, we discovered seven relatively independent constructs, three of which were specifically related to the presence of left hemispatial neglect: Left Attentional Processing, Line Bisection. and Word Reading. Impairments in two of these factors. Left Attentional Processing and Line Bisection, occurred together in most cases but also occurred independently in 38 cases. There were no cases in whom Word Reading was present without concomitant deficits in one or the other two factors. These three factors could not be distinguished neuroanatomically; that is, lesions were equally likely in the temporal/parietal cortex, dorsolateral frontal cortex, or in deep frontal structures. These data confirm the notion that hemispatial neglect is a complex and multifaceted disorder composed of cognitively independent processes. These processes, however, cannot be dissociated neuroanatomically based on currently available assessment techniques. (JINS, 1996, 2, 441–451.)

Simple sight-word reading tasks have demonstrated utility in the estimation of premorbid intelligence, although the effects of progressive dementia on such tasks has not been thoroughly examined. The present investigation sought to examine estimated IQ scores from the National Adult Reading Test-Revised (NART-R; Blair & Spreen, 1989) in relation to a WAlS-R-bascd (Wechsler, 1981) estimate of IQ in a series of patients with probable Alzheimer's disease across varying levels of dementia. Results suggest that while NART-R scores do show a decrement with dementia severity, this decline is mild, in contrast to traditionally based IQ scores and other measures of cognitive function, which show more marked declines. Similarly, compared with other tasks, the NART-R showed the strongest correlation with education across the sample as a whole, while the other indices were more related to level of dementia. These findings support the use of measures such as the NART-R in estimating premorbid intellectual functioning in patients at various levels of dementia severity, including those with more advanced cognitive deterioration. (JINS, 1996, 2, 551–555.)

This critical review examines mental retardation (MR) from a neuropsychological perspective. Competing definitions of MR are discussed and the prevalence is estimated. Descriptions are given of idiopathic MR and the five major identifiable prenatal causes of MR: fetal alcohol syndrome, Down's syndrome, fragile X syndrome, Prader-Willi syndrome, and Angelman syndrome. Similarities and differences among syndromes are examined. Cognitive deficits common to all disorders were in attention, short-term memory, and sequential information processing, whereas language and visuospatial abilities were varied. Neuroanatomical abnormalities common to all disorders were in the hippocampus and cerebellum; individual disorders typically showed a unique pattern of other neurological abnormalities. Both knowledge of individual MR-related disorders and comparative research between disorders are important for researchers and clinicians. Further research is called for in both areas. (JINS, 1996, 2, 159–176.)

We evaluated freehand picture production of familiar objects in patients with probable Alzheimer's disease. The overall recognizability of their drawings was significantly compromised. Error analyses revealed the production of category violations and the frequent inclusion of incorrect features in a picture that were borrowed from semantically related objects, suggesting difficulty distinguishing between items with overlapping feature sets in semantic memory. Analyses of individual patient drawing profiles also revealed that some patients are disproportionately compromised in expressing a particular perceptual feature, implicating difficulty at the level of perceptual processing. Regression analyses demonstrated the contribution of limited visual attentional resources. We conclude that impaired freehand drawing in probable Alzheimer's disease is multifactorial in nature. (JINS, 1996, 2, 226–235.)

This prospective study reinvestigates the effect of asymptomatic carotid artery disease on the cognitive outcome after cardiopulmonary bypass (CPB) (Harrison et al., 1989). Patients (N = 104) scheduled for cardiac surgery using CPB were classified in one of two groups based on the results of a preoperative duplex B mode Dopplcr scan of the internal carotid arteries. All patients received a neuropsychological examination before surgery, 8 days after surgery, and 6 months after surgery (n = 79). When group data are considered, patients showed evidence of selective cognitive dysfunction early after surgery. These dysfunctions were resolved by the sixth postoperative month. We found no indications that the presence of asymptomatic carotid artery disease increased the incidence of cognitive disturbances after CPB or differentially affected the postoperative performance. We conclude that mild to moderate asymptomatic carotid artery disease does not appear to play a major role in the genesis of postoperative neuropsychological sequelae. (JINS, 1996,2, 236–239.)

The effects of transcutaneous electrical stimulation on deficits of tactile perception contralateral to a hemispheric lesion were investigated in 10 right brain-damaged patients and in four left brain-damaged patients. The somatosensory deficit recovered, transiently and in part, after stimulation of the side of the neck contralateral to the side of the lesion, in all 10 patients with lesions in the right hemisphere, both with (six cases) and without (four cases) left visuo-spatial hemineglect, and in one left brain-damaged patient with right hemineglect. In three left brain-damaged patients without hemineglect, the treatment had no detectable effects. In one right brain-damaged patient, the stimulation of the side of the neck ipsilateral to the side of the lesion temporarily worsened the somatosensory deficit. These effects of transcutaneous electrical stimulation are similar to those of vestibular stimulation. The suggestion is made that these treatments modulate, through afferent sensory pathways, higher-order spatial representations of the body, which are pathologically distorted toward the side of the lesion. The modulatory effect is direction-specific: the defective internal representation of the contralesional side may be either partly restored, improving the disorder of tactile perception, or further impoverished, worsening the deficit. The possible neural basis of this modulation is discussed. (JINS, 1996, 2, 452–459.)

One hundred unselected brain-damaged outpatients received a standardized battery of numerical tests (EC301) and, independently, a questionnaire on numerical activities in daily life (ADL). Comparisons between the two types of measurement were drawn from the scorings for different functional components of the calculation and number processing system. Results indicated high ranking correlations between the two instruments. The EC301 battery generally proved more powerful than the questionnaire in detecting the presence of mild-todiscrete impairments, but some aspects of numerical difficulties in nonaphasic patients were scored higher on the ADL questionnaire. (JINS, 1996, 2, 177–180.)

Traditional methods for assessing the neurocognitive effects of epilepsy surgery are confounded by practice effects, test-retest reliability issues, and regression to the mean. This study employs 2 methods for assessing individual change that allow direct comparison of changes across both individuals and test measures. Fifty-one medically intractable epilepsy patients completed a comprehensive neuropsychological battery twice, approximately 8 months apart, prior to any invasive monitoring or surgical intervention. First, a Reliable Change (RC) index score was computed for each test score to take into account the reliability of that measure, and a cutoff score was empirically derived to establish the limits of statistically reliable change. These indices were subsequently adjusted for expected practice effects. The second approach used a regression technique to establish “change norms” along a common metric that models both expected practice effects and regression to the mean. The RC index scores provide the clinician with a statistical means of determining whether a patient's retest performance is “significantly” changed from baseline. The regression norms for change allow the clinician to evaluate the magnitude of a given patient's change on 1 or more variables along a common metric that takes into account the reliability and stability of each test measure. Case data illustrate how these methods provide an empirically grounded means for evaluating neurocognitive outcomes following medical interventions such as epilepsy surgery. (JINS, 1996, 2, 556–564.)

Recent modifications of the lexical model of oral reading make the prediction that under conditions where sublexical reading processes alone cannot achieve the target pronunciation (i.e., when words have exceptional spellings or when sublexical processes are impaired), patients with severe semantic impairment should have more difficulty reading aloud semantically impaired words than semantically retained words. In a battery of lexical-semantic and reading tasks, two neurologically normal control subjects and two subjects with probable Alzheimer's disease (AD) and only moderate semantic impairment read aloud all words accurately. One AD subject with severe semantic impairment was impaired in word reading but demonstrated no difference in reading words with regular and exceptional spellings. Another AD subject with severe semantic impairment read aloud without error virtually all regular and exception words. Neither severely impaired AD subject demonstrated any relationship between oral reading accuracy and semantic knowledge of exception words. These findings support a model of word reading incorporating lexical, nonsemantic processes by which lexical orthographic input representations directly activate lexical phonological output representations without the necessity of semantic mediation. (JINS, 1996, 2, 340–349.)