HIV infection often results in neuropsychological (NP) impairment. In order to assess the impact that HIV-related NP deficits may have on automobile driving, we evaluated 68 HIV-seropositive drivers using an NP battery and two PC-based driving simulations. Thirty-two participants were classified as NP impaired; most (72%) evidenced only mild impairment, and none met criteria for HIV-associated dementia. After controlling for degree of immunosuppression and disease stage, NP-impaired participants failed a previously validated driving simulation at a much higher rate than cognitively intact participants [OR = 5.3, 95% CI (1.7, 17.0), p = .006]. Similarly, on a simulation of city driving, NP impaired participants were more likely to fail based upon the number of accidents [OR = 6.1, 95% CI (1.5, 24.6), p = .01]. Simulator performance was predicted by functioning in a number of NP domains, with NP tests accounting for 13–30% of the variance on the simulations. Although it would be premature to extrapolate these findings to impairment in on-the-road driving, they do argue for greater attention to the impact that even mild HIV-related NP deficits may have on driving skills. (JINS, 1999, 5, 579–592.)

Few studies have examined the consequences of alcohol and drug abuse on TBI though they commonly co-occur. Both TBI and substance abuse independently result in neuropathological changes in the brain such as ventricular enlargement and cortical atrophy, thus it is reasonable to hypothesize that the combination of the two would result in more significant cerebral damage. In this study, 3 groups of patients—traumatically brain injured (TBI) with substance abuse (N = 19), TBI without substance abuse (N = 19), and substance abuse with no TBI (N = 16)—were compared with normal controls (N = 20) on several quantitative MRI (QMRI) measures. Since TBI most frequently occurs in older adolescents and young men, we examined only male participants between 16 and 30 years of age. Comparing young substance abusers to controls resulted in no QMRI differences. When controlling for head injury severity, the effects of substance abuse in combination with TBI resulted in greater atrophic changes than seen in any other group. TBI and substance abuse patients' neuropsychological test performances also were examined, and no differences were found among patient groups on any measures. These findings have implications for the deleterious interaction of substance abuse combining with TBI to result in greater neuropathological changes that can be detected by QMRI techniques. (JINS, 1999, 5, 593–608.)

We compared 7 mildly affected Huntington's disease (HD) patients to 7 age- and education-matched healthy controls (NC) on an odor detection test, the California Odor Learning Test, and the California Verbal Learning Test. Results demonstrated that odor detection sensitivity, but not group membership, accounted for significant variance in total olfactory learning. Both groups learned fewer items in the olfactory modality compared to the verbal modality, but retained a similar amount following a delay. No group differences were demonstrated for verbal recognition discriminability, but the HD group demonstrated significantly impaired odor recognition discriminability. Finally, odor detection provided excellent classification sensitivity and specificity between the patients and controls, suggesting that olfactory testing may provide a sensitive measure of the early disease process in HD. (JINS, 1999, 5, 609–615.)

Patients with frontotemporal dementia (FTD) often present with an asymmetric left or right-sided anterior cerebral perfusion abnormality that is associated with differential behavioral symptoms. However, whether patients with primarily right versus left FTD also have unique neuropsychological characteristics has not been previously investigated. Comparisons of 11 patients with right-sided FTD and 11 with left FTD indicated that the 2 patient groups showed relatively distinct cognitive profiles. Patients with right FTD exhibited relatively worse performance on PIQ than VIQ, and on select nonverbal executive tasks relative to their verbal analogs (e.g., design fluency < word generation; Picture Arrangement < word sequencing). In contrast, patients with left FTD showed the opposite pattern. In addition, the 2 patient groups differed on several absolute test scores; patients with right FTD demonstrated more errors and perseverative responses, and worse percent conceptual level responses, on the Wisconsin Card Sorting Test, while the left FTD patients obtained significantly worse scores on the Boston Naming Test, and Stroop word reading and color naming. Verbal and nonverbal memory, mental speed, visual perceptual–constructional skill, and IQ subtest scaled scores did not significantly differ between groups. These data indicate that FTD should not be viewed as a unitary disorder, and that neuropsychological testing holds promise for the differential diagnosis of right versus left FTD. (JINS, 1999, 5, 616–622.)

This is the fifth symposium to appear in the Journal of the International Neuropsychological Society (JINS). This symposium was developed in tandem with a Memory Disorders Research Society conference symposium on semantic memory in probable Alzheimer's disease (AD); the conference was held in Boston in October, 1998. Three of the conference presenters agreed to submit papers based on their talks to this JINS symposium. A concerted effort was made to solicit additional papers from researchers who have consistently weighed in on either the storage-loss or retrieval-difficulty side of the debate regarding semantic memory in AD, and from researchers who have obtained some evidence consistent with one view as well as some evidence consistent with the other view. In the end, not only was the theoretical continuum fairly well represented, but the methodological continuum, with regard to the types of tasks used and the degree to which the tasks required implicit versus explicit utilization of semantic knowledge, was also well covered.

Two experiments are reported that explore the influence of strength of the prime–target relationship on the observed priming effects in young, healthy old, and individuals diagnosed with dementia of the Alzheimer type (DAT). In Experiment 1, participants were auditorily presented primes (FURNITURE) and after varying delays presented visual targets that were (1) high-strength related (e.g., SOFA), (2) low-strength related (e.g., RUG), or (3) unrelated control words (e.g., COW or DEER). The results indicated that the DAT individuals produced relatively larger priming effects than both the young and the healthy old, but these data could be accommodated by increases in effect size due to general slowing of response latencies. In Experiment 2, the same cross-modal priming paradigm was used with ambiguous words presented as primes (e.g., BANK) and either high-dominant (e.g., MONEY) or low-dominant (e.g., RIVER) words as targets. The results of Experiment 2 produced a qualitatively distinct pattern of priming that indicated DAT individuals only produced priming for high-dominant targets and not for low-dominant targets, whereas, the healthy control groups produced equivalent priming for both high- and low-dominant targets. The discussion focuses on the implication that these results have for the interpretation of semantic priming effects, in general, along with implications for the apparent semantic memory loss in DAT individuals. (JINS, 1999, 5, 626–640.)

While it has been commonly assumed that a deficit in semantic memory underlies many of the clinical and cognitive features of early Alzheimer's disease (AD), there has been little agreement on what constitutes a proper theoretical description of this impaired system. Currently, most theories of this disorder fall into two categories: those that posit degraded semantic representations, and those that posit impaired retrieval operations with relatively intact semantic representations. It is argued that each position has both empirical and logical disadvantages that have prevented the development of a consensus on how to describe the pathology of semantic memory in AD. In this paper we present the details and supportive evidence for an alternative account of the semantic memory deficit of AD: the Gain/Decay hypothesis. The core claim of the Gain/Decay hypothesis is that a reduction in the time constant of spreading activation in AD produces dynamic changes in the availability of semantic representations that depend on the time frame in which this information must be accessed. The implications of this hypothesis for a range of experimental and clinical phenomena are discussed, as are possible biological correlates of the hypothesized alterations in the modulation of activation. (JINS, 1999, 5, 641–658.)

Impairments to either perceptual or word-retrieval processes have been hypothesized to explain confrontation naming impairments in patients with Alzheimer's disease (AD). This study measured the effects of structural similarity, which affects perceptual processing, and name frequency, which affects word retrieval, on naming latency and accuracy in 16 AD patients and 16 age-matched controls. AD patients named pictures more slowly and made more errors than control participants. Their naming accuracy was disproportionately affected by name frequency, but not by structural similarity. The findings indicate that the processing of structural properties of objects is unaffected in early-stage AD, and suggest that word-retrieval impairments underlie the naming deficit in AD. (JINS, 1999, 5, 659–667.)

Sixty individuals with probable Alzheimer's disease (AD) and 48 normal elders were given a task in which they had to judge the relatedness of concepts as a means of evaluating semantic memory. Very mild AD patients performed similarly to normal elders. Mild AD patients were significantly inferior in performance to normals but the pattern of their performance did not suggest a loss of conceptual knowledge. Moderate AD patients were significantly inferior in performance to mild AD patients, and 8 moderate AD patients (compared to 1 mild AD patient) were unable to do the task. The pattern of performance of moderate patients suggests that conceptual knowledge may degrade and ultimately be lost. (JINS, 1999, 5, 668–675.)

We used a novel apparatus called the flags board to elicit similarity judgments from 32 Alzheimer's disease (AD) patients and 32 elderly normal (EN) controls for two 12-member conceptual domains, ANIMALS and (musical) INSTRUMENTS. Based on Pathfinder and multidimensional scaling (MDS) analyses, performance by AD patients was nearly identical to that of EN controls for ANIMALS. Performance differed for INSTRUMENTS, but the AD group's Pathfinder network was found to agree with the intuitions of a panel of 18 raters as well as the EN group's. MDS analysis showed no deficit on abstract dimensions for the AD group, for either domain. The results are discussed in the context of degradation versus preservation of semantic memory in AD. (JINS, 1999, 5, 676–684.)

This study examined whether Alzheimer patients can make elaborative inferences based on the semantic context provided by a sentence. More specifically, if presented with the name of a category in a sentence do they, like normals, infer (instantiate) the particular member of that category most appropriate to the meaning of the sentence (e.g., if a sentence mentions a container of juice, do they infer it is a bottle). Patients were presented with a sentence containing the name of a concrete category. The sense of the sentence was consistent with a low-dominant member of that category. Patients were then shown drawings of four members of that category and asked to select the one appropriate to the sentence. They were later asked to name the drawings. If semantic information is degraded in Alzheimer patients for those objects Alzheimer patients cannot name (as has been claimed), then AD patients should be unable to carry out the type of elaborative semantic inference required to instantiate. Results showed that Alzheimer patients were highly accurate at instantiating even objects they could not name. This is consistent with a relative preservation of semantic knowledge about concrete objects in Alzheimer patients. (JINS, 1999, 5, 685–691.)

The ability to generate words from phonemic (i.e., words beginning with ‘F,’ ‘A,’ and ‘S’) and semantic (i.e., animals, fruits, and vegetables) categories was assessed longitudinally in patients with Alzheimer's disease (AD; N = 59) and normal controls (NC; N = 59). Patients with AD performed worse than NC participants on both tasks at each of 4 annual evaluations and exhibited greater impairment relative to controls on the semantic-category task than on the phonemic-category task. In addition, the performance of the patients with AD declined over time on both tasks, but the rate of decline was faster on the semantic-category than on the phonemic-category task. Examination of individual responses across the annual evaluations revealed that patients with AD were more consistent than NC participants in failing to generate previously produced semantic-category, but not phonemic-category, items in all years following the 1st year in which the item was not produced. These results are consistent with the notion that patients with AD suffer a gradual deterioration of the organization and content of semantic memory as the disease progresses. (JINS, 1999, 5, 692–703.)

The psychological and neuropsychological changes of aging and dementia have been a topic of study for decades, if not centuries. It is only more recently, however, that technological changes have allowed the biological processes triggering the changes of aging to be uncovered. The overlap between these two sciences, the relationship between cognitive aging and the study of biological aging, is an emerging area of research. The study of aging, however, is confounded by the close association between aging and the development of particular diseases. Older people are far more likely than young people to suffer from multiple illnesses. Furthermore, older people are far more vulnerable to specific types of diseases such as heart disease, cancer, and dementia. The relationship between the onset of the aging process and the development of dementing disorders such as Alzheimer's disease is of particular interest.

Most clinical neuropsychologists find themselves, at one time or another, foraging through their collection of folders, boxes, and texts to locate reliability, validity, and normative data for some of the more commonly used neuropsychological tests in an elderly population. In their forward, Tuokko and Hadjistavropoulos indicate that this book is designed to compile the range of normative data on the more commonly used neuropsychological tests into one source that can be easily accessed and integrated by the clinician. In addition to presentation of normative data relating to the geriatric population, a critique of each instrument's standardization and normative data is presented as well. While not all-inclusive of measures used by the typical neuropsychologist, it does cover the majority of tasks for which good normative data on the elderly exist.