Biomedical subjects

N Butters

Publications and source records attributed to N Butters.

At least 109 records · Page 6Linked to original sources

PubMed1986

Some analyses of forgetting of pictorial material in amnesic and demented patients.

Three experiments evaluating the rate of forgetting of pictorial stimuli in amnesic, demented, and normal control subjects are reported. When prolonged exposures of pictorial material were used to equate recognition performance after a 10-min delay, alcoholic Korsakoff (AK) patients and patients with Huntington's Disease (HD) demonstrated normal rates of forgetting over a 1-week period. In addition to replicating previous findings with AK patients, these results are consistent with recent suggestions that retrieval, not storage, deficiencies characterize the HD patients' memory problems. The second experiment explored whether the AK and HD patients learned as much about the features of the pictorial stimuli as did the normal subjects. After the subjects viewed a series of pictorial stimuli, recognition was assessed 10 min later using the whole pictures, isolated main features of the pictures, or isolated peripheral features of the pictures. The results showed that, with prolonged exposure times, the two patient groups did not differ from the normal control group in terms of the features of the stimuli they analyzed and remembered. The third experiment evaluated the rate of forgetting of pictorial material of two groups ("young" and "old") of normal subjects, one group ("old") having viewed each picture for 1 s and the other group ("young") for .5 s. Although the two groups did not differ in recognition performance 10 min after presentation, the young subjects who viewed each picture for .5 s showed more rapid forgetting over a 1-week period. This finding indicates that similar recognition scores do not necessarily signify equal learning under all exposure conditions.

Alcohol Amnestic Disorder↗

PubMed1986

Asking the right questions: problem solving in male alcoholics and male alcoholics with Korsakoff's syndrome.

The performance of alcoholics and alcoholics with Korsakoff's syndrome was compared with that of nonalcoholic controls on a task which required the generation of a series of questions for the solution of object and digit/letter identification problems. Each subject attempted to determine which of a set of stimuli (objects, letters, or numbers) the examiner had arbitrarily preselected as correct. The nonalcoholic control subjects asked constraint-seeking questions which reduced alternatives by inquiring about general categories (e.g., "Is it a tool?"). In contrast, the two groups of alcoholic patients assumed the far less efficient strategy of asking hypothesis-scanning and pseudo-constraint questions which provided information only about one of the possible stimuli (e.g., "Is it the saw?"). This similarity in the problem-solving strategies of alcoholics both with and without Korsakoff's syndrome is consistent with the hypothesis that the problem-solving deficits of Korsakoff patients are apparent before the acute onset of their amnesic symptoms. These deficits may be due to alcohol-induced damage to the anterior and posterior cerebral cortical association areas which mediate problem-solving and visuoperceptual functions.

Alcohol Amnestic Disorder↗

PubMed1986

The appreciation of affect in alcoholic Korsakoff patients.

The purpose of this study is to assess the appreciation of affective components of words in patients with insult to diencephalic and subcortical brain structures thought to subserve emotional expression. Six alcoholic Korsakoff patients were presented with triadic comparisons composed of names of birds, predators, and birds of prey. The principal findings revealed that normal control subjects associate birds of prey with both birds and predators, but Korsakoff patients associate the birds of prey significantly more often with birds than predators. Three-dimensional spatial representations of patients' associations revealed that normals cluster birds at one extreme of a dimension and predators at the other extreme, with birds of prey lying in an intermediate position. Korsakoff patients also clearly separate the birds from the predators and form tight clusters within each of these groups, but they associate the birds of prey noticeably with the birds. Moreover, Korsakoff patients displayed, on another dimension of the spatial representation, their difficulty appreciating that a word could possess multiple category memberships. The findings are discussed with respect to the multifaceted dementia seen in Korsakoff Syndrome, and are interpreted to provide guarded support for the claim that insult to particular diencephalic and subcortical brain structures interferes with the appreciation of affective material in particular circumstances.

Adult↗

PubMed1985

The continuity hypothesis: the relationship of long-term alcoholism to the Wernicke-Korsakoff syndrome.

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.

Adult↗

PubMed1985

Memory disorders associated with Huntington's disease: verbal recall, verbal recognition and procedural memory.

Two experiments were conducted to evaluate the hypothesis that the memory disorders of Huntington's Disease (HD) patients are characterized by deficiencies in both retrieval mechanisms and the acquisition of procedural (skill-based) information. In the first study, verbal recall and recognition tests were administered to HD patients, amnesics and normal control (NC) subjects. Although the two patient groups were impaired relative to NC subjects on both recall and recognition of word lists, the performance of the HD patients was superior to that of the amnesics on the recognition test. In the second experiment early HD (EHD), advanced HD (AHD), amnesic and NC subjects were compared in the acquisition of the 'Tower of Hanoi' puzzle. Both the NC subjects and EHD patients acquired the solution of this puzzle after repeated trials, whereas the AHD and amnesic patients evidenced little improvement. However, on a recognition test assessing memory for facts about the puzzle, both the EHD and AHD patients were superior to the amnesic subjects. These results are consistent with the retrieval hypothesis but are equivocal with regard to the HD patients' proposed deficit in skill learning. Since the 'Tower' puzzle may rely heavily on both problem solving and skill learning capabilities, it may be of limited value in searching for double dissociations between patient groups and the acquisition of skill-based and data-based knowledge.

Adult↗

PubMed1985

The effect of associations and expectations on lexical decision making in normals, alcoholics, and alcoholic Korsakoff patients.

This study examined whether patients with Korsakoff's disease suffer from increased PI during encoding. The ability of the name of one category, e.g., BIRD, to prime the processing of members of another category, e.g., BODY PARTS, in a lexical decision task was used to assess the amount of PI during encoding. This task required a subject to inhibit the normal associations to BIRD. Young normals (25 years), older normals (48 years), alcoholics (45 years), and alcoholic Korsakoff patients (59 years) performed two lexical decision tasks. In the first experiment, the appearance of the neutral prime XXX 750 msec before the probe signaled that if the probe was a word, there was a 75% chance that it was from a particular category (e.g., BODY PARTS). The prime facilitated reaction time for words from the expected category for all four groups. The prime slowed reaction time for words that were not from the expected category for the young normals but did not influence reaction time for unexpected words for the three older groups. The second experiment was identical to the first except that a category word was used as the prime. The category word used as the prime was unrelated to the category of the words that were likely to follow it. For example, BIRD might be used to signal the likelihood that the word would be from the category, BODY PARTS. Again, young normals were slower to respond to unexpected probe words, but the three older groups were not. Again, the prime facilitated reaction time for expected words for the young normals, older normals, and alcoholics. However, the word prime did not facilitate reaction time for expected words for the alcoholic Korsakoff patients. That the word prime did not facilitate reaction time for the Korsakoff patients was viewed as evidence that they were unable to inhibit its normal associations and were more sensitive to PI from these associations than the other subjects.

Adult↗

PubMed1985

Alcoholic Korsakoff's syndrome: some unresolved issues concerning etiology, neuropathology, and cognitive deficits.

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. While 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 the nucleus basalis of Meynert has questioned the role of the medial diencephalon 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 more accurately characterized as a "basal forebrain" than as a "diencephalic" amnesia.

Alcohol Amnestic Disorder↗

PubMed1984

Dissociations between skill learning and verbal recognition in amnesia and dementia.

Patients with Huntington's disease (HD), patients with alcoholic Korsakoff's syndrome, and normal control subjects were compared on tests of skill learning (mirror reading) and verbal recognition. Like previously reported results, the patients with Korsakoff's syndrome acquired the mirror-reading skill at a normal rate but were severely impaired in their recognition of the words used on the mirror-reading task. In contrast to the amnesic patients, the demented patients with HD were retarded in their ability to acquire this skill but showed normal verbal recognition. Besides emphasizing substantial differences in the anterograde substantial differences in the anterograde memory disorders of these two patient populations, the results suggest that the memory disorder of patients with HD may appear much more severe when recall rather than recognition test paradigms are employed. This failure of recall by the patients with HD may be due to an inability to generate strategies necessary to search their short- and long-term memories.

Alcohol Amnestic Disorder↗

PubMed1984

Alcohol consumption and premature aging. A critical review.

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.

Aged↗

PubMed1984

Retrograde amnesia in Parkinson's disease.

Retrograde amnesia was assessed in demented and non-demented Parkinson's patients using a test of remote memory spanning the years from 1920-1979. Results indicated that the demented patients 1) scored significantly below normal controls and 2) had equal impairment for all time periods. This pattern was like that seen in other dementing illnesses (i.e., Huntington's and Alzheimer's diseases), but different from that in amnesic disorders, such as Korsakoff's syndrome. The data, therefore, suggest qualitative differences in pattern of remote memory loss between the dementias and amnesic syndromes.

Aged↗

PubMed1984

The clinical aspects of memory disorders: contributions from experimental studies of amnesia and dementia.

Many of the standardized memory tests employed by clinical neuropsychologists fail to demonstrate important differences in the memory disorders of amnesic and demented patients. To exemplify this heterogeneity of amnesic symptoms, the anterograde and retrograde amnesias of patients with Huntington's Disease (HD) and of patients with alcoholic Korsakoff's syndrome are compared. While both patient groups have similar MQs, they differ dramatically in their recall and recognition memory and in their ability to acquire procedural (rule-based) information. The Korsakoff patients are impaired in both recall and recognition memory but are able to acquire and retain mirror reading skills. In contrast, the patients with HD are impaired in their acquisition of procedural knowledge and in verbal recall although their recognition memory approaches normality. The importance of such information for the assessment of the patients' memory disorders is discussed.

Alcohol Amnestic Disorder↗

PubMed1984

Oculomotor function in Wernicke-Korsakoff's syndrome: I. Saccadic eye movements.

Saccadic eye movements from three patients diagnosed as having Korsakoff's syndrome and one patient who had suffered the acute Wernicke stage of the disorder were examined for changes in saccadic characteristics. The three Korsakoff patients showed increased saccadic latencies; two of the three also had reduced saccadic peak velocities and increased saccadic durations. A higher than expected incidence of hypometric saccades was also found in all four patients; saccadic intrusions were recorded in two Korsakoff patients. These abnormal oculomotor responses were found 2-7 years after the onset of the Korsakoff's syndrome and are consistent with the cerebellar and frontal lobe dysfunction reported in this patient group.

Alcohol Amnestic Disorder↗

PubMed1984

Oculomotor function in Wernicke-Korsakoff's syndrome: II. Smooth pursuit eye movements.

Smooth pursuit eye movements were studied in three patients with alcoholic Korsakoff's syndrome, one with Wernicke's encephalopathy, and an age-matched control. Horizontal smooth pursuit eye movements were abnormal in all patients: peak eye velocity and the ability to sustain smooth eye velocity were reduced. Also, smooth pursuit gain began to decrease at relatively low target velocities (i.e., 8-10 degrees). These data demonstrate a severe disturbance in smooth pursuit function long after the clinically apparent oculomotor abnormalities have passed.

Aging↗

PubMed1983

Cognitive loss and recovery in long-term alcohol abusers.

The nature of the memory and visuospatial defects associated with chronic alcoholism, and the recovery of these functions, were investigated in a large group of alcoholic men and well-matched nonalcoholic controls. Both young and old alcoholics displayed significant impairments on tasks requiring the learning of novel associations and the holding of information in memory over longer delay intervals. The recovery of cognitive skills was found to depend on the length of abstinence and the particular behavioral functions examined. Whereas psychomotor skills and short-term memory improved significantly with prolonged abstinence, long-term memory was impaired even after seven years of continuous sobriety. We propose that recovery of short-term memory reflects reestablishment of cortical functioning, while the persistent long-term memory defect indicates more permanent damage to diencephalic structures.

Alcohol Drinking↗

PubMed1983

Ablations of the mammillary nuclei in monkeys: effects on postoperative memory.

A new procedure was developed for ablating the mammillary nuclei in nonhuman primates via direct visual exposure. Using this technique, monkeys receiving lesions of the mammillary nuclei were compared to control animals after surgery to assess the retention of preoperatively acquired visuospatial discriminations and subsequent postoperative ability to attain a demanding spatial memory task. Although the lesions proved to be accurate and complete, no changes in gross behavior or deficits in preoperatively acquired visual and spatial behaviors were noted. The monkeys with mammillary body lesions were, however, impaired in their ability to acquire postoperatively the demanding spatial memory task. These findings are consistent with previous investigations suggesting that the mammillary bodies are involved in the acquisition of spatial discriminations and skills.

Animals↗

PubMed1983

The effect of verbal mediators on the pictorial memory of brain-damaged patients.

Patients with alcoholic Korskoff's syndrome, Huntington's Disease, Alzheimer's Disease or right-hemisphere damage were administered a picture recognition task in which they attempted to associate specific human and animal figures with particular scenic backgrounds. Under one condition (no-story), no explicit verbal cues were provided to help the patients associate the figures with the scenes; in a second condition, stories, stories linking the figures to the background scenes were read to the patients during the study period. Although all four patient groups were impaired in picture-context recognition under the no-story condition, the groups differed significantly in their ability to use the stories to improve their pictorial memory. The Huntington and right-hemisphere patients' picture recognition showed significant improvement when stories were provided, whereas the Korsakoff and Alzheimer patients failed to use this verbal material in a productive manner. The groups also differed in their tendency to make intrusion (i.e., perseverative) errors on the picture-context recognition task. These group differences may be related to the combination of language, cognitive and motivational deficits associated with each disease.

Adult↗

PubMed1983

Cognitive functioning of alcoholic females: an exploratory study.

The effects of long-term alcoholism on the cognitive functioning of female alcoholics was examined through direct comparisons to equivalent male alcoholics and to both male and female controls on a battery of neuropsychological tests. As expected male alcoholics demonstrated deficits in abstraction, memory and visuoperceptual functioning whereas female alcoholics demonstrated deficits in abstraction and visuoperceptual functioning only. Apparently alcoholic females have fewer cognitive deficits than equivalent alcoholic males. Specifically after 30 days of sobriety alcoholic females were no different than control males or females on tests of memory whereas male alcoholic males were impaired. This finding if replicated implies the possibility of less structural brain damage in female alcoholics than equivalent alcoholics.

Adult↗

PubMed1983

A comparison of the effects of long-term alcohol abuse and aging on the performance of verbal and nonverbal divided attention tasks.

The purpose of this study was to assess two versions of the hypothesis that alcohol abuse results in premature aging of the brain and of cognitive functioning. The performances of detoxified long-term alcoholic was compared with that of nonalcoholic controls on three divided attention tasks known to be sensitive to aging. While both forms of the premature aging hypothesis predicted that alcoholics should perform more poorly than controls, the hypotheses differed in their predictions of the interactions between the effects of alcohol and normal aging. The results showed that while all three tasks were sensitive to age, only two were affected by long-term alcohol abuse. On one of the tests affected by both age and alcohol abuse, the performance of both young and old alcoholics was equally impaired whereas on the other, only the older alcoholics had significant difficulties. Based on these findings it was concluded that there was only partial overlap between the effects of alcohol and aging, and that neither of the two forms of the premature aging hypothesis could predict the observed pattern of results.

Aging↗