The present study examined the relationship between rate of cognitive decline in patients with Alzheimer's disease (AD) and the integrity of the network of associations that comprise their semantic knowledge. The integrity of the semantic network of 12 AD patients was determined by comparing their networks to a standard normal control network derived with Pathfinder analysis, a multidimensional graphic analysis technique. A simple linear regression analysis, comparing the degree of semantic network deterioration with rate of cognitive decline as measured by the difference between the Dementia Rating Scale (DRS) scores obtained at the time of the testing of semantic knowledge (Year 1) and one year later (Year 2), was highly significant (r2 = .84; p < .001). These results suggest that a sensitive measure of the structural deterioration of semantic knowledge may be useful for predicting the rate of progression of cognitive changes in patients with AD. (JINS, 1995, I, 297–303.)

A modified way of administering the process dissociation procedure to the false fame paradigm is described. Multidimensional signal detection theory (SDT) is used to correct for recollection as well as familiarity false alarms, and two experiments are reported that compare this method of false alarm correction with the hybrid procedure preferred by Jacoby et al. (1993). In experiment 1, it is shown that recollection and familiarity are lost at the same rate in normal subjects over a delay of 1 d when an SDT analysis is used. Analysis with the hybrid procedure fails to find any forgetting over the 1-d delay. In experiment 2, amnesics are shown to have preserved familiarity in the face of impaired recollection for names when the results are analyzed by either method. An additional analysis showed that the amnesics' familiarity was normal even for relatively novel surnames. The SDT analysis also revealed that the amnesics, relative to controls, showed a conservative recollection and a liberal familiarity response bias. The results indicate that it is important to correct for recollection as well as familiarity false alarms. (JINS, 1995, I, 469–482.)

Alzheimer's disease (AD) is characterized by progressive decline in memory, language and other cognitive functions. Deficits in attentional processes have also been suggested. A simple reaction time (RT) task was used to assess global attention in AD. The length and consistency of a warning signal given prior to the response stimulus were manipulated to determine if patients with AD and age-matched controls benefit from predictability in RT tasks. Overall reaction time was slower in the AD group than in the and control group. Both groups demonstrated significant improvement in RT with long warning signals compared to short warning signals, but only the control group benefited from the consistency of the warning. (JINS, 1995, I, 56–61.)

This experiment explored knowledge of four types of semantic relations (superordinate category, part, property, and function) in Alzheimer's disease (AD) subjects and age- and education-matched controls. Moderate AD subjects showed the greatest disruption on functional relations, intermediate disruption on part and property relations, and the least disruption on category relations; mild AD subjects showed a similar pattern but significant deficits only on functions. We suggest that the disproportionate deficit on functions reflects a greater cognitive complexity of functions than other semantic relations that renders them more vulnerable either to disrupted processing or to structural degradation of the network of associations among semantic concepts. (JINS, 1995, 1, 568–574.)

The current review was conducted to address the ongoing debate regarding the presence or absence of neuropsychological impairment in asymptomatic HIV-Type 1 (HIV-1) seropositive individuals. Results were summarized from 57 studies that compared the performances of seropositive asymptomatic and seronegative individuals. Overall, the differences observed between median rates of impairment for asymptomatic (35%) and seronegative (12%) groups provided the clearest indication of deficits in asymptomatics. In addition, five variables were examined as possible contributors to inconsistencies found in the literature: mode of infection, test battery type, test battery size, sample size, and method of data analysis. Of these variables, only mode of infection and test battery size appeared to substantially influence the outcome of the studies reviewed with regard to identifying neuropsychological impairment in asymptomatics. (JINS, 1995, I, 304–315.)

Aged and young adults were tested by category cued recall after learning with category cues (CCR) or with item cues (ICR). CCR was about twice ICR for both aged and young adults. The aged recalled less than the young and did not benefit as much from greater encoding specificity and deeper processing in CCR. ICR and CCR were correlated, so that expected CCR can be predicted from ICR. The regression of CCR on ICR was linear for young adults, but was piecewise linear for the aged, showing that the relationship between ICR and CCR was not uniform for the aged adults. Lower than expected CCR by a subset of aged without clinical dementia may be a sign of preclinical dementia. (JINS, 1995, I, 483–493.)

Fourteen young adolescents with specific reading disabilities received short term neuropsychological treatment–specifically left hemisphere (LH) or right hemisphere (RH) stimulation–in a clinical pilot project. The effects on single-word and passage reading were evaluated when the language of treatment was either Dutch (mother tongue) or English (foreign language). Transfer effects across the two languages were also studied. In general, the results indicate that these short term interventions may prove successful for the treated language and with the additional transfer to a second (not treated) language. (JINS, 1995, I, 494–500.)

We administered a spatial version of the Delayed Recognition Span Test (DRST), a working memory task performed abnormally by patients with basal ganglia disease, to a group of 96 HIV-seropositive and 83 seronegative subjects with a high prevalence of substance abuse. For comparison purposes, we also administered the Symbol-Digit Modalities Test (SDMT) and the Trail Making Test (TMT), measures which detect HIV-related mental slowing efficiently in gay men but are nonspecifically impaired in subjects with a history of substance abuse. As predicted, scores on the TMT and the SDMT did not discriminate the groups, but HIV-seropositive subjects had significantly shorter spatial spans (p < .007) and DRST total scores (p < .005). These effects could not be attributed to differences in age, education, estimated intelligence, or psychological distress, because the groups were well matched on these variables. The DRST is a promising measure of HIV-related cognitive dysfunction in substance abusers, who are often nonspecifically impaired on psychomotor tasks. These preliminary data also indicate that working memory function should be studied further in HIV-seropositive subjects. (JINS, 1995, 1, 575–580.)

Humans learn skilled acts in order to effectively interact with their environment. A loss of the ability to perform skilled acts is termed apraxia. Apraxia has been thought to be of theoretical interest, but the ecological implications of apraxia are controversial and have not been fully studied. We examined ten patients with unilateral left hemisphere cerebral infarctions (eight of whom were apraxic) and compared their mealtime eating behavior to a group of neurologically normal, age-matched controls. The stroke patients were less efficient in completing the meal. They made more action errors and were less organized in the sequencing of mealtime activities. Because the patients made more errors while using tools than when performing nontool actions, their deficit could not be accounted for by an elemental motor deficit. A positive relationship was found between mealtime action errors and the severity of apraxia. These findings suggest that limb apraxia may adversely influence activities of daily living. (JINS, 1995, I, 62–66.)

Psychosocial outcome at one year post-injury was examined prospectively in 466 hospitalized head-injured subjects, 124 trauma controls, and 88 friend controls. The results indicate that head injury is associated with persistent psychosocial limitations. However, the presence and extent of limitations are related to the demographics of the population injured, to other system injuries sustained in the same accident, and particularly to the severity of the head injury. More severe head injuries are associated with limitations implying greater dependence on others including poorer Glasgow Outcome Scale (GOS) ratings, dependent living, unemployment, low income, and reliance on family and social subsidy systems. Head injury severity is more closely related to more objective indices of psychosocial outcome (e.g., employment) than to self-perceived psychosocial limitations, such as measured by the Sickness Impact Profile (SIP). (JINS, 1995, I, 67–77.)

Significant anoxia may cause a variety of neuropathologic changes as well as cognitive deficits. We have recently seen 3 patients who have suffered severe anoxic episodes all with initial Glasgow Coma Scores (GCS) of 3 with sustained coma for 10–14 d. All 3 patients had extended hospitalizations and rehabilitation therapy. A neuropsychological test battery was administered and volumetric analyses of MRI scans were carried out in each case at least 6 mo postinjury. Two of the patients display distinct residual cognitive and neuropathologic changes while 1 patient made a remarkable recovery without evidence of significant morphological abnormality. These three cases demonstrate, that even with similar admission GCS, the outcome is variable and the degree of neuropsychological impairment appears to match the degree of morphologic abnormalities demonstrated by quantitative MR image analysis. An important finding of this study is that even though subjects with an anoxic insult exhibit severe cognitive and memory impairments along with concomitant morphologic changes, their attention/concentration abilities appear to be preserved. MR morphometry provides an excellent means by which neural structural changes can be quantified and compared to neuropsychological and behavioral outcomes. (JINS, 1995, I, 501–509.)

Neuropsychological impairment and DSM-III-R Axis I psychiatric diagnoses were evaluated in a heterogenous group of HIV seropositive individuals and seronegative individuals with similar risk factors for HIV infection. Neuropsychological and psychiatric disorders were common in the HIV seropositive group, but there were no relationships between these two aspects of neuropsychiatric dysfunction in seropositive patients. Results indicate that psychiatric disorders in HIV seropositive individuals tend to predate infection and decrease over time following knowledge of seroconversion, suggesting that they are primarily a function of psychosocial factors. Neuropsychological disorders are specific to HIV seropositive patients and tend to increase over time following seroconversion, suggesting that they are due to neurological effects of HIV-infection. (JINS, 1995, 1, 581–588.)

In this study, verbal learning and memory following pediatric closed-head injuries (CHI) using the children's version of the California Verbal Learning Test (CVLT). Participants included 47 children, ages 5–16 yr, with a history of CHI, and 47 matched, noninjured controls. Children with CHI performed more poorly than controls on the CVLT, although their deficits varied qualitatively as a function of injury severity. Those with mild/moderate injuries performed as well as controls on learning trials, but they recalled proportionally fewer words after a delay (although their recognition was intact). Severely injured children demonstrated deficits in learning, delayed recall, and recognition, compared to controls. The groups did not differ in learning characteristics, but children with severe CHI exhibited more intrusions than controls. Pediatric CHI are associated with specific disturbances in verbal learning and memory similar to those of adults with CHI but different from those of children with other developmental and neurological disorders. JINS, 1995, I, 78–87.)