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Qualitative features of the neuropsychological test performance of individuals with dementia of the Alzheimer type (DAT) were examined in a population-based study. Qualitative error scores were derived from measures of verbal and figural memory, verbal fluency and confrontation naming for 38 patients with clinically diagnosed DAT, 236 normal elderly (NE) individuals, and 72 others who were questionably demented and at risk (AR) for DAT. Persons with DAT made a greater proportion of intrusion and perseverative errors, and more lexical and semantic naming errors, than the NE participants. These measures provided fair specificity but poor sensitivity for the diagnosis of DAT, and a logistic model based on these measures correctly classified 98% of the NE participants, but only 29% of the DAT participants. The AR participants demonstrated a pattern of errors that was highly similar to that of the DAT patients, and when their scores were subjected to the logistic model, 90% were classified as NE and 10% as DAT. These results indicate that specific error types that have been associated with DAT in self-referred or clinic-based samples also occur in the general population to a greater degree in individuals with DAT or questionable dementia than in NE individuals. Furthermore, these qualitative features may have some diagnostic usefulness in that their presence provides reasonable specificity for DAT or questionable dementia.

Patterns of memory performance were examined for 9 participants with HIV-associated dementia (HAD), 15 HIV-seropositive participants without dementia, and 15 HIV-seronegative controls. Episodic and semantic memory were assessed using the California Verbal Learning Test, the Boston Naming Test, and Verbal Fluency tests. The HAD group showed deficits in episodic memory, with relative sparing of semantic memory. In addition, results suggest a retrieval deficit in HAD rather than a deficit in retention of information. This pattern is consistent with the presence of a subcortical dementing process and supports findings from previous neuropathological, neuroimaging, and neuropsychological studies suggesting that subcortical brain dysfunction is frequently associated with HIV disease (e.g., Navia, Jordan,Price, 1986).

This study reports the sensitivity and specificity of the Clock Drawing Test (CDT) for detecting dementia of the Alzheimer type in a community-dwelling sample of elderly subjects. Forty-two patients with clinically diagnosed Alzheimer's disease and 237 cognitively intact subjects were administered the CDT as part of an epidemiological study of aging and dementia. Three individual measures of clock drawing performance (quantitative score, qualitative score, and combined quantitative and qualitative score) were determined for each participant. When qualitative elements such as errors and strategies were incorporated into the CDT score, the sensitivity was 84% and the specificity was 72%. The findings suggest that a CDT score which evaluates qualitative and quantitative features provides reasonably good discrimination between normal elderly individuals and DAT patients. However, the CDT appears to have limited utility as a single screening instrument in the community. Instruments such as the Dementia Rating Scale (Mattis, 1976) provide better discrimination of DAT, indicating that functions such as memory and verbal fluency need to be assessed during screening.

In 3 experiments, participants generated category exemplars (e.g., kinds of fruits) while a voice key and computer recorded each response latency relative to the onset of responding. In Experiment 1, mean response latency was faster when participants generated exemplars from smaller categories, suggesting that smaller mental search sets result in faster mean latencies. In Experiment 2, a concurrent secondary task increased mean response latency, suggesting that slowed mental processing results in slower mean latencies. In Experiment 3, the mean response latency of Alzheimer's participants was faster than that of elderly controls, which is consistent with the idea that the semantic memory impairments of Alzheimer's disease patients stem primarily from a reduction in available items (as in Experiment 1) rather than retrieval slowing (as in Experiment 2).

The present study examined neuropsychological (NP) functioning and associated medical, neurological, brain magnetic resonance imaging (MRI), and psychiatric findings in 389 nondemented males infected with Human Immunodeficiency Virus-Type 1 (HIV-1), and in 111 uninfected controls. Using a comprehensive NP test battery, we found increased rates of impairment at each successive stage of HIV infection. HIV-related NP impairment was generally mild, especially in the medically asymptomatic stage of infection, and most often affected attention, speed of information processing, and learning efficiency; this pattern is consistent with earliest involvement of subcortical or frontostriatal brain systems. NP impairment could not be explained on the bases of mood disturbance, recreational drug or alcohol use, or constitutional symptoms; by contrast, impairment in HIV-infected subjects was related to central brain atrophy on MRI, as well as to evidence of cellular immune activation and neurological abnormalities linked to the central nervous system.

This study compared the discriminative utility of problem-solving and memory tasks in patients with Alzheimer's and Huntington's disease and in age-, education-, and gender-matched normal control subjects. Problem-solving was assessed with a modified version of the Wisconsin Card Sorting Test. Memory was measured with a 10-item, 6-trial version of the Buschke Selective Reminding Test. Receiver Operating Characteristic curves were plotted to determine which measure provided the highest sensitivity (i.e., hit rate) and specificity (i.e., correct rejection rate). Both tests provided excellent detection of dementia (88 to 98% classification accuracy), but were less robust in differentiating between dementia groups. Findings underscore the suitability of both measures to detect mild dementia, but emphasize the importance of specific memory measures to differentiate between cortical and subcortical dementia.

Recent studies comparing the explicit and implicit memory disorders of Huntington's disease (HD) and Alzheimer's disease (AD) patients have yielded new insights into the specificity of the memory disorders associated with basal ganglia dysfunction. Patients with HD have severe deficiencies in retrieving information from either episodic or semantic explicit memory. This retrieval deficit is not confounded by impairments in storage, rapid forgetting, intrusion errors and a deterioration of the structure of semantic knowledge. While HD patients perform normally on implicit memory tasks involving lexical, semantic and pictorial priming, they are impaired on implicit tests which require the initiation and/or modification of central motor programs. It is concluded that the basal ganglia play a specific but important role in memory although the processes they mediate are different from those dependent on the integrity of the hippocampus and diencephalon.

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.

The organization of semantic memory in patients with Alzheimer's disease (AD) was investigated with a triadic comparison task. A multidimensional scaling statistic was used to analyze proximity data and to generate 3-dimensional cognitive maps that were then compared by a discriminant function analysis. The results suggest that the structure of semantic memory in AD patients differs from that of elderly normal controls (NC) in 2 ways. First, AD patients are less consistent in using the attributes (predation, domesticity, and size) of concepts. Second, AD patients focus primarily on concrete perceptual information (size), whereas NC Ss stress abstract conceptual knowledge (domesticity). These results are consistent with the notion that AD is characterized by a breakdown in the structure of semantic knowledge.

Recent research has demonstrated that patients with dementia of the Alzheimer type (DAT) evidence more rapid forgetting than do patients with Huntington's disease (HD). The present study focused on whether such group differences translated into measures with adequate sensitivity and specificity at different stages of these disorders. It was found that measures of forgetting (i.e., savings scores) based upon the Logical Memory and Visual Reproduction tests of the Wechsler Memory Scale--Revised had satisfactory to excellent sensitivity and specificity in differentiating DAT and HD patients from healthy control subjects. Savings scores also had good sensitivity and specificity in differentiating DAT from HD in the early stages of the diseases. However, unsatisfactory specificity may limit the utility of savings scores in differentiating among patients with moderate DAT and HD.

Eight patients with alcoholic Korsakoff's syndrome were compared to age-matched groups of normal controls and nonamnesic chronic alcoholic patients using magnetic resonance imaging (MRI). Quantitative image-analytic techniques were used to estimate volumes of ventricular and cortical cerebrospinal fluid (CSF), as well as cortical and subcortical grey matter structures. For the nonamnesic alcoholics, these volume analyses revealed large CSF increases with some circumscribed decreases in grey-matter volumes. In contrast, alcoholic Korsakoff patients showed widespread reductions in grey matter volumes in addition to CSF increases, with greatest reductions observed in diencephalic structures. The volume losses that best differentiated the Korsakoff patients from the alcoholic controls included losses in anterior portions of the diencephalon, mesial temporal lobe structures, and the orbitofrontal cortices. These findings suggest that damage to structures other than the mesial thalamic nuclei, such as the hypothalamus and hippocampus, may contribute to the Korsakoff patients' amnesic symptoms.

The tendency of patients with dementia of the Alzheimer type (DAT) and Huntington's disease (HD) to produce prior-item intrusion errors on a figural memory task was assessed. Patients' and elderly control subjects' immediate recall of figures from the Visual Reproduction Test (VRT) of the Wechsler Memory Scale (WMS) was scored for the presence of prior-figure intrusion errors (i.e., characteristics unique to one figure included in the reproduction of a subsequent figure). Results indicate that both patient groups produced more prior-figure intrusion errors than did the NC group, and that DAT patients made significantly more intrusion errors in their reproductions than did HD patients matched for overall severity of dementia. These data suggest that prior-item intrusion errors are evident on figural as well as on verbal memory tasks and that DAT patients are more likely to produce such errors than are equally demented patients with a "subcortical" dementia.

This paper discusses some of the general methods by which laser light has been used in engineering measurement. Some objectives set for optical measurement in this field are high repeatability, good resolution and employment of non‐contacting equipment, in the sense of both light source and detector being some tens of millimetres away from the object avoiding obstruction to other processes.

The potential of holograms to achieve improved communication in education and training tasks has been investigated. Experiments in education have been carried out at the secondary level and additionally observations of pupil reactions have been observed for younger children. The holograms were found to command attention which is an important aspect of teaching. Some typical examples of the use of holograms included communication of visual information recorded from rare museum exhibits and science examples in physics and biology. The holograms were capable of displaying images in true perspective, thus conveying the same information as a model or real object, but being conviniently reproduced and requiring a minimum of maintenance and storage space. The experiments were extended to training in two study areas where interest was expressed by tutors and there was a willingness to cooperate in the creation and use of training material in holographic form. The areas concerned were in foundry technology and textiles. The requirements in foundry technology were to assist students in the comprehension of the solid form from engineering drawings and the reverse requirement to produce adequate engineering drawings to define a cast form. In the textile case holograms were used to assist the comprehension of the relationship between stitch form and fabric properties and to identify machine faults from stitch irregularities. The number of students formally tested was small leaving statistical analysis inconclusive, but tutors using holograms found that students learned faster when holograms were made available. As a parallel investigation, three undergraduate engineering students used holographic communication as the subject of their project. Subjects included a tutorial display of a carburettor showing the outside form with air and fuel passages in correct perspective. Other examples showed the transmission arrangement in a Mercedes car and the arrangement of cams for a new ‘Locstitch’ textile machine. Holograms also found use in communication between a UK laboratory and overseas manufacturer to explain the effect of bearing lubricant cavitation. The work was carried out during a period of rapid development of the holographic process and the initial holograms were difficult to use since they required special monochromatic light sources. Later developments used white light reflection holograms which were much more convinient to use. The cost of producing holograms can also be expected to fall. All holograms used in the trials were individually made in the laboratory, but developments in ‘printed’ holograms promise reduced costs in the future. It is to be expected that holograms will in future be used in distance learning packages and possibly in textbooks.

It is theoretically and experimentally established that speckle pattern interferometric contouring may be used to directly generate a fringe pattern which is a measure of the difference in geometry of two nominally identical nonspecular objects. The limitations and range of application of the technique are discussed and some basic considerations concerning the decorrelation of speckle patterns resulting from wavelength change are presented.

The application of holography as a routine method of analysing the vibrations in aero-engine compressor and turbine blades and discs is studied to overcome the disadvantages of the usual sand pattern and piezo-electric crystal contact probe methods. The Stetson-Powell time average fringe hologram technique of vibration analysis is used to investigate the nodal patterns of a 3-in and 6-in compressor blade together with those of a 10-in diameter turbine disc and the disc with a full set of blades. Two real time holographic methods of vibration analysis are also studied. The hologram system and apparatus are simplified to enable the normal methods of clamping the vibrating components to be utilized. A completely self-contained unit that is capable of both taking the hologram and photographing the reconstructed image has been developed. The unit is a box-like structure which is simple to operate and can be used in a normal inspection bay environment for objects up to 2 ft diameter.

The surface to be studied is illuminated with laser light and two images are formed, displaced relative to one another in the image. Speckle pattern interferometry is used to measure phase changes between the two images resulting from deformation of the surface. A fringe system is obtained showing contours of constant slope resolved in the direction of image displacement. A comparison is made with result obtained by holographic interferometry.

Laser light has widened the horizons of applied interferometry both by simplifying existing techniques and opening up a new field where holography is utilized to provide a master or reference wavefront. Whilst retaining many of the advantages of classical interferometry the new methods are simple in application and will accommodate almost any surface finish. Examples of application include an investigation of performance for pressure transducer diaphragms and the development of an engine rocker design. A slight modification to the technique enables measurement and visualization of vibration amplitudes and modes. Application to a turbo-charger impeller investigation and a turbine blade inspection are given.

When a photographic plate is doubly exposed to a laser speckle pattern and is given a small displacement, in its own plane, between exposures then it will exhibit linear fringes in its optical Fourier transform. This effect may be used to display correlation between two different intensity distributions which are obtained by interference of two coherent speckle patterns before and after a relative phase change; surface displacement may be displayed by interference of the speckle pattern image of a surface with another, coherent, speckle pattern.

Recent neuropsychological and neuropathological investigations with long-term alcoholics suggest that the etiology and neuropathology of the Wernicke-Korsakoff syndrome are more complex than previously believed. Although problem-solving and visuoperceptual deficits seem to develop slowly during decades of alcoholism, the amnesic symptoms associated with Korsakoff's syndrome may appear acutely when severe malnutrition and alcoholism are combined. Furthermore, the report that alcoholic Korsakoff patients, like patients with Alzheimer's disease, have endured a substantial neuronal loss in structures comprising the basal forebrain suggests a role for this brain region in the alcoholic patients' amnesic syndrome. Some initial demonstrations of similarities in the memory disorders of alcoholic Korsakoff and Alzheimer patients indicate that Korsakoff's syndrome may be accurately characterized as a "basal forebrain" as well as a "diencephalic" amnesia.

Memory performance of patients with the clinical diagnosis of Alzheimer's disease was compared with performance of patients with alcoholic Korsakoff's syndrome and patients with Huntington's disease. Although all patient groups exhibited impairment on tests of verbal memory, only patients with Alzheimer's disease exhibited impaired priming. Priming is an unconscious expression of recently encountered material, and it is intact even in severely amnesic patients. Because mildly demented patients with Alzheimer's disease exhibited impaired priming, damage to brain structures in addition to those damaged in the amnesic syndrome must occur at a relatively early stage of the disease process.

During the past 10 years numerous investigations concerned with the neuropsychological, neuropathological and etiological factors involved in alcoholic Korsakoff's syndrome have been published. The neuropsychological research has focused on the patients' anterograde and retrograde amnesias, and several theories based upon current models of human information processing have been advanced as partial explanations of the amnesic syndrome. While neuropathological investigations have continued to implicate midline diencephalic structures in the chronic symptoms of this disorder, some very recent studies have begun to assess the role of neurotransmitters in the patients' memory disorders. The etiology of the disorder also appears to be more complex than once believed. Animal studies demonstrating the neurotoxicity of alcohol have suggested that the patients' severe memory deficits may be due to an interaction of malnutrition and the toxic effects of alcohol. Behavioral investigations reporting that non-Korsakoff alcoholics have memory deficits qualitatively similar to those of Korsakoff patients support the idea that Korsakoff's syndrome is not acute but may develop slowly during decades of alcohol abuse.

The WMS-R represents a significant improvement over the original version of the WMS. Patterns of performance on the five WMS-R indices successfully differentiated patients with a "cortical" (that is, DAT) from patients with a "subcortical" (that is, HD) dementia. The differences between ACI and GMI also indicated that DAT patients' attention and concentration were better preserved than those of equally demented HD patients. Analyses of the differences between GMI and DMI indicated that rapid forgetting was more apparent for DAT than for HD patients in the early stages of these disorders. When savings scores for the Logical Memory and Visual Reproduction tests were used to examine retention over a 30-minute period, both mildly and moderately demented DAT patients demonstrated more rapid forgetting than did HD patients with similar levels of cognitive decline. Discriminant analyses performed with these indices of forgetting showed 95 per cent accurate classification of DAT and elderly controls, and 79 per cent correct classification of DAT and HD patients. Assessment of the patients' tendencies to make prior-item intrusion errors on the Visual Reproduction tests of the WMS and WMS-R yielded significant differences between patient groups and the two versions of the test. Patients with DAT made significantly more prior-figure intrusion errors than did HD patients on both versions of the VRT, but the original WMS form of this figural memory test was more likely to elicit such errors than was the revised version. Despite many improvements in the revised scale, a number of limitations still exist including standardization and a lack of norms for elderly individuals, as well as failures to include tests of verbal recognition and adequate measures of nonverbal memory.

Research conducted during the past ten years has demonstrated that alcoholics resemble yet older nonalcoholics on a variety of behavioral, radiological, electrophysiological, and regional blood flow measures of brain function. These similarities have led to speculation that excessive alcohol consumption causes a premature aging of the brain that, in turn, is responsible for the characteristic structural and functional changes seen in detoxified alcoholics. In this chapter, we discuss some of the conceptual and methodological problems associated with what has become known as the premature-aging hypothesis and review a series of recent studies that have used neuropsychological, computerized-tomography, and evoked-potential techniques to test its validity. We conclude that there is very little compelling empirical support for this intriguing hypothesis and suggest that the neurobehavioral changes seen in alcoholics are merely the reflection of a diffusely distributed pattern of brain damage.

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.

The performance of a group of detoxified male chronic alcoholics was compared with that of age-matched nonalcoholic controls on a memory task which at face value seemed relevant to daily life--i.e., learning to associate people's names with their faces. The alcoholics not only made more errors while learning the face-name associations than did the controls, but fewer of them were able to reach the learning criterion. However, 1 hour later, the alcoholics were nevertheless able to recognize all of the faces and names used during acquisition. The savings scores for the alcoholics, an index of the relative number of face-name associations retained during the 1-hour interval, did not differ significantly from those of the controls. These results demonstrate that the alcoholics' paired-associate learning deficit on this ecologically relevant task is related to their failure to form associations rather than to deficiencies in recognition memory or perceptual processes.

Although alcoholic Korsakoff's syndrome has traditionally been considered an acute disorder related to a nutritional deficiency, recent evidence demonstrating that ethanol may be neurotoxic has raised the possibility that the perceptual, problem-solving, and memory deficits associated with this chronic neurological disorder may develop slowly over decades of alcohol abuse. A review of the recent cognitive literature provides only limited support for this "continuity hypothesis." Long-term alcoholics, as with patients with alcoholic Korsakoff's syndrome, are impaired on numerous visuoconceptual and learning tasks, but there is little or no evidence that the information-processing deficits underlying the two patient groups' anterograde memory problems are similar. Furthermore, experimental and clinical studies of retrograde amnesia have noted only mild remote memory impairments in non-Korsakoff alcoholics as well as clear indications that alcoholic Korsakoff patients' severe loss or access to remote memories occurs acutely with the onset of Wernicke's encephalopathy. It is concluded that while the continuity hypothesis has heuristic value, there is still insufficient evidence to place the Korsakoff patient, the detoxified long-term alcoholic, and the heavy social drinker at different points on a single continuum of cognitive impairment.

Compared with control subjects, alcoholics with Korsakoff's psychosis were significantly impaired in performance on the digit-symbol subtest of the Wechsler Adult Intelligence Scale and in four tasks assessing related processes. Other alcoholics showed similar, but not as severe, visuoperceptive deficits when compared with controls.

Four investigations were conducted concerning the relationship between sulcus principalis and the monkey's spatial capacities. The results of the first two studies indicated that lesions limited to the middle third of sulcus principalis but including both the superior and inferior banks resulted in severe deficits on spatial delayed-alternation and plsace reversal learning. Lesions of the anterior or posterior sectors of principalis or of the periarcuate region produced only mild, if any, impairments on the same spatial tasks. The third study demonstrated that the midprincipalis sector could be differentiated from the anterior and posterior sectors of principalis on anatomical as well as functional bases. The midprincipalis sector had heavy projections to the cingulate and retrosplenial regions while the posterior third had many efferent connections with the parietal lobe. The anterior third had limited projections to the cingulate region and none to the parietal lobe. The fourth investigation demonstrated that intact neural structures could assume some spatial functions after sequential destruction of sulcus principalis. Monkeys with serial, in comparison to one-stage, bilateral ablations of sulcus principalis demonstrated normal performance on a delayed-response task and on some place reversals, and partial recovery of delayed-alternation.

Holographically reconstructed wavefronts can be degraded by small local movements of the recording emulsion, during processing. A method of substantially reducing this movement, by releasing strain in the emulsion prior to exposure, is described, together with a simple experimental arrangement to detect the movement. This method is useful in real-time hologram interferometry, to give smoother fringe patterns which can be more easily and accurately interpreted.