Biomedical subjects

W C Heindel

Publications and source records attributed to W C Heindel.

At least 19 recordsLinked to original sources

PubMed1998

Repetition priming with nonverbal stimuli in patients with dementia of the Alzheimer type.

Perceptual repetition priming was examined in patients with dementia of the Alzheimer type (DAT) and normal control (NC) participants using a task involving the discrimination of geometric designs that had either a continuous ("closed") or discontinuous ("open") perimeter. With the open stimuli, the groups displayed significant and equivalent levels of priming after immediate repetition of the stimuli, whereas only the NC group primed significantly over a delay of three intervening items. Neither group demonstrated significant priming with the closed stimuli. Results indicate that under some conditions DAT patients can exhibit normal repetition priming with stimuli that do not have preexisting representations but that (due possibly to a deficiency in the level of steady-state cortical activation) this priming dissipates more rapidly in DAT patients than in NC participants.

Aged↗

PubMed1997

Non-associative lexical priming is impaired in Alzheimer's disease.

A word-fragment completion task was used to assess long-term, non-associative lexical priming in patients with probable Alzheimer's disease (AD) and age- and education-matched elderly normal control (NC) subjects. Despite equivalent baseline performance, the AD patients exhibited less facilitation in their ability to complete word fragments from having previously read the intact words than did the NC subjects. The AD patients were also impaired relative to NC subjects on an explicit recognition memory task, but there was no relationship between explicit memory performance and priming for either group. These results are consistent with previous demonstrations of impaired semantically-based priming in patients with AD and extend the domain of their impairment to priming that is predominantly based on lexical activation.

Aged↗

PubMed1996

Gender differences in the behavioral manifestations of Alzheimer's disease.

OBJECTIVE: To examine the relationship between gender and specific types of behavior problems that occur in patients with Alzheimer's disease. DESIGN: This was an observational study using the Dementia Behavior Disturbance Scale to quantify and define behavioral problems encountered by caregivers. Multiple regressions were used to control for the possible influence of dementia severity as measured by the Mini-Mental State Examination and the duration of dementia. SETTING: Patients were sampled from the outpatient dementia clinics of Roger Williams Hospital and Miriam Hospital in Providence, Rhode Island. PARTICIPANTS: A total of 125 patients with probable Alzheimer's disease, defined by NINCDS-ADRDA diagnostic criteria, were included in the study. There were 75 women and 50 men. MAIN OUTCOME MEASURES: Caregivers rated the presence and frequency of 28 different behavior problems from the Dementia Behavior Disturbance Scale. Domains of behavior disturbance were then defined by a factor analysis of the data. RESULTS: Male and female groups were comparable for the demographic variables of age, education, and duration of dementia, as well as severity of depression, degree of cognitive impairment and overall severity of behavior disturbance. Among the six behavior factors that were defined, two were significantly related to gender. One factor, which included apathy and vegetative signs, was related to male gender; a second factor, which included reclusiveness and emotional lability, was related to female gender. CONCLUSIONS: Although overall severity of behavior disturbance in Alzheimer's disease may be related primarily to severity in dementia, significant differences in the types of behaviors manifested exist between males and females with the disease.

Aged↗

PubMed1995

Decline in working memory associated with HIV infection. HNRC Group.

HIV infection has been associated with decline in a number of cognitive functions that are components of 'working memory'. Thus, tests of working memory that require the interaction of these components may be particularly sensitive to cognitive dysfunction that arises from HIV infection. To assess this possibility, working memory was examined in 147 HIV-seropositive (HIV+) and 38 HIV-seronegative (HIV-) males using the Reading Span Test and the Digit Span subtest from the Wechsler Memory Scale-Revised (WMS-R). Speed of information processing, a component of some working memory tasks, was assessed with a version of the Sternberg Memory Scanning task. Results indicated that symptomatic HIV+ subjects were impaired relative to HIV- control subjects on the Reading Span and Digit Span tests. Asymptomatic and mildly symptomatic HIV+ groups exhibited a trend toward impairment on these tests, and on the whole, a greater proportion of HIV+ subjects than HIV- subjects were impaired. The groups did not differ significantly in information processing speed. These results indicate that deficits in working memory are apparent in at least a subset of HIV-infected individuals. These deficits are most apparent in symptomatic HIV+ individuals, but the decline may begin during the asymptomatic phase of infection.

Adult↗

PubMed1995

Methodological considerations in estimating speed of cognitive operations.

Individuals infected with Human Immunodeficiency Virus (HIV) and having cognitive impairment have been described as having slow mentation. Data supporting this proposition come from a variety of sources, including Sternberg's (1966) item recognition memory task. The procedure nominally provides an index of speed of mental operations, independent from input/output demands. However, since the original use of this procedure in the 1960s, advances in cognitive psychology have revealed many of its limitations. The purpose of the present study was to examine the psychometric characteristics of this task. Each participant performed the Sternberg item recognition task twice, 6 mo apart. The stability of the estimate of the slope of regression equations and for zero intercept ranged from excellent (r = .87) to poor (r = .30), and the data from many individual subjects could not be reliably modelled using multiple linear regression techniques. These data, as well as those from previous research, demonstrate the limited practical use of this task in clinical samples. Furthermore, as cognitive psychological theory has advanced in the past 30 yr, the conceptual underpinnings of the procedure have essentially evaporated.

AIDS Dementia Complex↗

PubMed1995

The biasing effect of verbal labels on memory for ambiguous figures in patients with progressive dementia.

This experiment investigated the effects of verbal labels on recognition memory for ambiguous visual figures in patients with Alzheimer's disease (AD), patients with Huntington's disease (HD), and matched normal control subjects. The study employed ambiguous figures that could be interpreted in two different ways. During the study phase each figure was presented together with a verbal label that corresponded to one interpretation of the figure. After a 30-min retention interval a recognition memory test was given during which the study figures and distractor figures were presented one at a time without verbal labels. For each study figure two distractor figures were employed, each corresponding to a different interpretation of the study figure. The patients' overall recognition memory performance was severely impaired compared to control subjects. However, all subject groups tended to produce responses and response latencies to distractor items that were consistent with the verbal labels presented during the study phase. This bias effect occurred in the AD patients despite the fact that their recognition memory performance was at chance level. Indeed, there was no significant difference in the bias evidenced by the AD and HD patients and their respective matched control subjects. The bias effects were obtained in an explicit memory task, and the findings are discussed in terms of unconscious influences on explicit memory processes.

Adult↗

PubMed1994

The relationship of quantitative brain magnetic resonance imaging measures to neuropathologic indexes of human immunodeficiency virus infection.

OBJECTIVE: To directly examine the relationship between magnetic resonance imaging (MRI) abnormalities and neuropathologic changes in the brains of patients with the acquired immunodeficiency syndrome. DESIGN: A total of 17 brains from patients with acquired immunodeficiency syndrome for which postmortem MRI scans were available were used in this study. Volumes of cortical gray matter, deep gray matter, and abnormal white matter were estimated from the MRIs of the left hemispheres of the formalin-fixed brains from patients with acquired immunodeficiency syndrome using quantitative morphometric techniques. Quantitative estimates of human immunodeficiency virus, gliosis, and neocortical synaptic and dendritic density were obtained from the corresponding right hemispheres. Quantification of human immunodeficiency virus and gliosis was performed on all 17 specimens, while quantification of synaptic and dendritic density was performed on 10 of the 17 specimens. SETTING: All specimens were obtained from patients with the acquired immunodeficiency syndrome who underwent autopsy between 1990 and 1992 at the University of California-San Diego Medical Center and the San Diego (Calif) Department of Veterans Affairs Hospital. RESULTS: No association was found between MRI volumes and gliosis, a nonspecific marker of central nervous system damage. Significant and regionally specific relationships were obtained, however, between the severity of central nervous system human immunodeficiency virus infection and the MRI volume estimates of gray matter and abnormal white matter. In addition, a significant association was observed between cortical gray matter volumes and cortical synaptic density. CONCLUSION: These findings indicate that the quantitative morphometric analysis of MRIs in patients may provide sensitive in vivo markers of neuropathologic changes associated with human immunodeficiency virus infection of the brain.

Brain Diseases↗

PubMed1994

Verbal memory performance of patients with human immunodeficiency virus infection: evidence of subcortical dysfunction. The HNRC Group.

In the present study, the California Verbal Learning Test (CVLT) was administered to symptomatic HIV+ (n = 31), asymptomatic HIV+ (n = 94), and HIV-normal control (HIV-NC) (n = 40) subjects to assess the prevalence and nature of their verbal memory deficits. Symptomatic HIV+ subjects were significantly impaired relative to HIV-control subjects on CVLT measures of acquisition and retention, and were significantly less likely than control subjects to use a semantic clustering strategy to support recall. The performance of the asymptomatic HIV+ subjects fell between those of the symptomatic HIV+ subjects and HIV-controls on almost every CVLT measure. A linear discriminant function analysis (DFA) was used to compare the performances of these three groups to Alzheimer's disease (AD). Huntington's disease (HD), and normal control (NC) subjects on three CVLT measures, including total recall over five learning trials, intrusion errors, and a derived score of delayed recognition discriminability minus the final learning trial. Significant differences were found between the number of symptomatic HIV+ subjects classified as HD (32%), AD (3%), and normal (65%), the number of asymptomatic HIV+ subjects classified as HD (16%), AD (1%), and normal (83%), and the number of HIV-NC subjects classified as HD (2%), AD (0%), and normal (98%). The profile of verbal memory deficits exhibited by the subgroup of impaired HIV+ subjects was similar to that of patients with HD, a prototypical subcortical dementia, and different from that of patients with AD, a prototypical cortical dementia. This finding is consistent with reports of the predominance of subcortical neuropathological changes associated with HIV infection.

AIDS Dementia Complex↗

PubMed1994

Memory systems in normal and pathological aging.

Normal memory depends on a number of interdependent systems whose specialized contributions are dissociable at both cognitive and neurobiological levels of analysis. Guided by this multiple systems view of memory, this review provides a selective survey of recent studies on cognitive and neurobiological aging. Taken together, the results suggest that memory decline in human aging partly reflects a compromise of executive memory processes supported by frontal lobe regions of the brain, combined with a deterioration of explicit memory capacities supported by the hippocampal system. Defining how deficits in multiple memory systems interact to account for cognitive aging remains a significant challenge.

Adolescent↗

PubMed1992

Sensorimotor disinhibition in Parkinson's disease: effects of levodopa.

It has been known for some time that patients with Parkinson's disease (PD) have difficulty executing simultaneous motor acts, yet the pathophysiology underlying this impairment remains uncertain. We examined the possibility that these dual-task deficits stem from defective sensorimotor mechanisms producing interference between the motor programs underlying the two tasks. Patients with PD and normal control subjects were tested on their ability to maintain steady-state force with one hand while performing a force-reaction time task with the other hand. Although performance was worse on the dual-task than on the single-task condition for both subject groups, only the patients with PD demonstrated significant interference between the two tasks. The interference across tasks improved in 87% of the patients with PD when tested after treatment with carbidopa/levodopa (Sinemet). These findings support the contention that, in patients with PD, disturbances in the execution of simultaneous motor performance may be due to sensorimotor disinhibition.

Carbidopa↗

PubMed1991

The biasing of weight judgments in Alzheimer's and Huntington's disease: a priming or programming phenomenon.

The performances of Huntington's disease (HD) patients and patients with dementia of the Alzheimer type (DAT) were compared on an adaptation-level task involving the judgment of weights. In this task, subjects were first exposed to either a relatively heavy (heavy bias) or a relatively light (light bias) set of weights, and were later asked to rate the heaviness of a standard set of 10 weights using a 9-point scale. Patients with DAT and intact control subjects both perceived the standard set of weights as heavier following the light bias trials and lighter following the heavy bias trials, despite the DAT patients' poor explicit memory for the initial biasing session. In contrast, the weight judgments of the HD group as a whole was not significantly influenced by prior exposure to relatively heavy or light weights, and the size of the bias effect for this group was significantly correlated with the severity of their dementia. It is suggested that the impaired biasing performance of the HD patients, like their previously demonstrated impairment in motor skill learning, is due to a motor programming deficit resulting from neostriatal dysfunction.

Alzheimer Disease↗

PubMed1990

Pictorial priming and cued recall in Alzheimer's and Huntington's disease.

A picture fragment test was used to compare the priming and cued recall performances of patients with Huntington's disease (HD), patients with dementia of the Alzheimer type (DAT), and neurologically intact normal control (NC) subjects. On the pictorial priming test, subjects were asked to say "the first thing you think of" when shown incompletely drawn pictures, half of which were previously exposed to the subject during an unrelated naming task. Normal controls and HD patients, but not DAT patients, demonstrated similar increases in their ability to identify fragmented versions of previously seen pictures relative to novel pictures. These results are consistent with the previously observed pattern of preserved and impaired verbal priming ability in HD and DAT patients, respectively. The NC subjects, as expected, also demonstrated better performance on the cued recall than on the priming version of the picture fragment test, whereas the HD patients evidenced the opposite relationship on these two tasks and DAT patients were found to be equally impaired on both tests. This finding provides further support for the notion that HD patients' memory impairment is characterized primarily by an inability to initiate systematic retrieval strategies.

Aged↗

PubMed1990

Longitudinal evaluation of dementia of the Alzheimer type: a comparison of 3 standardized mental status examinations.

We administered 3 commonly employed tests of mental status (the Information-Memory-Concentration test [IMC], the Mini-Mental State Examination [MMSE], and the Dementia Rating Scale [DRS]) to 92 patients with probable dementia of the Alzheimer type. The 3 tests were readministered to 55 of the patients (2-year subgroup) approximately 1 year later, and administered a 3rd time to 20 of the patients (3-year subgroup) approximately 2 years after their initial assessment. In all cases, scores on the 3 tests were highly correlated with each other. Examination of the annual rate of change (ARC) in score for the 2-year subgroup revealed an average decline of -3.24 error points on the IMC, 2.81 points on the MMSE, and 11.38 points on the DRS. Of the 3 tests, only the DRS evidenced greater sensitivity to change with increasing dementia severity. In the 3-year subgroup, the ARC between years 1 and 2 was not correlated with ARC between years 2 and 3 for any of the 3 tests. This finding suggests that a patient's rate of progression in 1 year may bear little relationship to future rate of decline.

Aged↗

PubMed1989

Differentiation of Alzheimer's disease and Huntington's disease with the Dementia Rating Scale.

Patients with dementia of the Alzheimer type (DAT) and Huntington's disease (HD) were assessed with the Dementia Rating Scale, a brief mental status examination that provides a global dementia score and subtest scores for attention, initiation, construction, conceptualization, and memory capacities. Although the patients with DAT and the patients with HD were precisely matched in terms of total Dementia Rating Scale score, different subtest score profiles emerged. Patients with DAT were more impaired than patients with HD on the Memory subtest, whereas patients with HD were more impaired than patients with DAT on the initiation subtest. These results are indicative of qualitative differences in the cognitive impairment of the two disorders and demonstrate that such differences can be elucidated with brief mental status examinations.

Aged↗

PubMed1989

Dispositional correlates of hypnosis: a phenomenological approach.

An attempt was made to construct and validate a questionnaire measure of hypnotic-like experiences based on Shor's (1979) 8-dimension phenomenological analysis of hypnosis. Separate item pools were developed to measure each disposition: Trance, Nonconscious Involvement, Archaic Involvement, Drowsiness, Relaxation, Vividness of Imagery, Absorption, and Access to the Unconscious. Based on preliminary testing (total N = 856), a final questionnaire was produced containing 5 items measuring normal, everyday experiences in each domain. Results from a standardization sample (N = 468) showed that each of the subscales, except for Archaic Involvement, possessed satisfactory levels of internal consistency and test-retest reliability. Factor analysis indicated that 6 subscales loaded highly on a common factor similar to the absorption construct (Tellegen & Atkinson, 1974), while items pertaining to Relaxation and Archaic Involvement formed separate factors. Validation testing on 4 samples receiving the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A) of Shor and E. Orne (1962) (total N = 1855) showed that the Absorption and Trance dimensions correlated most strongly with HGSHS:A; the correlations with Drowsiness, Relaxation, and Nonconscious Involvement approached 0. The scales derived from Shor's analysis, however, did not improve the prediction of hypnotizability over that obtained with the absorption scale (Tellegen & Atkinson, 1974).

Humans↗

PubMed1989

Neuropsychological evidence for multiple implicit memory systems: a comparison of Alzheimer's, Huntington's, and Parkinson's disease patients.

The performances of patients with dementia of the Alzheimer type (DAT), patients with Huntington's disease (HD), and demented and nondemented patients with Parkinson's disease (PD) were compared on 2 tests of implicit memory that do not require the conscious recollection of prior study episodes: (1) a pursuit-rotor motor learning task and (2) a lexical priming test. The HD patients were found to be impaired on the motor learning but not the lexical priming task, whereas the DAT patients evidenced the opposite relationship on these tasks. The demented, but not the nondemented, PD patients were found to be impaired on both tests of implicit memory. For both the HD and PD patients, deficits on the motor learning task correlated significantly with severity of dementia but not with level of primary motor dysfunction. The noted double dissociation between HD and DAT patients indicates that different forms of implicit memory, all of which are intact in amnesia, are dependent upon distinct neuroanatomic systems. Motor skill learning may be mediated by a corticostriatal system, whereas verbal priming may depend upon the integrity of the neocortical association areas involved in the storage of semantic knowledge. The results for the PD patients suggest that the demented PD patients have endured damage to the neurologic systems subserving both motor learning and lexical priming.

Alzheimer Disease↗

PubMed1988

Impaired learning of a motor skill in patients with Huntington's disease.

The ability of patients with Huntington's disease (HD), patients with dementia of the Alzheimer's type (DAT), and amnesic patients (AMN) to acquire the motor skills underlying a pursuit rotor task was assessed. Differences between groups in initial levels of performance were minimized by adjusting the rotation speed of the disk. The HD and DAT groups were also administered a verbal recognition span test. The results showed that the DAT, AMN, and intact control groups all significantly improved their time on target over six test blocks whereas the HD group was severely impaired in the acquisition of this motor skill. On the verbal recognition span test, the DAT and HD groups were significantly and equally impaired, but the HD group evidenced better immediate and delayed recall than did the DAT group. These results provide further evidence that the basal ganglia are critically involved in the acquisition of motor skills.

Alzheimer Disease↗

PubMedDate not supplied

Retrograde amnesia in patients with Alzheimer's disease or Huntington's disease.

Retrograde amnesia (RA) was studied in patients with Huntington's disease (HD) or Alzheimer's disease (AD) using an updated version of the remote memory battery originally developed by Albert, Butters and Levin. Regardless of whether remote memory was measured by unaided recall or cued recall, HD patients exhibited deficits that were equally severe across decades. RA was more severe in AD than in HD patients and the AD patients recalled significantly more items from the 1940s and 50s than from the 60s, 70s or 80s. The AD patients also displayed dysnomia, while the HD patients did not. Naming difficulties appeared to contribute to the poor overall performance of the AD patients, but did not account for the temporal gradient of their RA. These findings, like recent reports focusing on these patients' ability to learn new information and to search semantic memory, indicate that the processes underlying AD and HD patients' memory failures are distinct.

Adult↗