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Query: UMLS:C0002622 (amnesia)
 5,520 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The relationship between recall and recognition has been a central topic for the study of memory. A test of alternative views about recall and recognition was arranged by studying amnesic patients. In amnesia, damage has occurred to a brain system important for declarative (conscious) memory, but skill learning, priming, and other forms of nonconscious memory are intact. Recall and recognition were found to be proportionately impaired in amnesic patients, and confidence ratings for the recognition judgments were commensurate with the level of impaired performance. The results are contrary to views that either recognition memory or associated confidence judgments are ordinarily supported significantly by nonconscious memory. The results favor the view that recall and recognition are related functions of declarative memory and equivalently dependent on the brain system damaged in amnesia.
J Exp Psychol Learn Mem Cogn 1992 Jul
PMID:On the relationship between recall and recognition memory. 138 10

In this experiment, we examined whether a group of well-characterized amnesic patients would exhibit normal priming for novel nonverbal materials after a single exposure. Both amnesic patients and normal control subjects studied line figures and were then given a priming test in which they were asked to reproduce both old (studied) and new (unstudied) figures after a brief exposure. The measure of priming was the number of old patterns drawn correctly relative to the number of new patterns drawn correctly. Both subject groups reproduced more old patterns than new patterns, and the effect was similar in the two groups. In contrast, amnesic patients were significantly impaired on a recognition memory test for the items that had been presented. This study contributes to recent evidence that implicit memory can support the rapid acquisition of novel verbal and nonverbal information. Perceptual priming for such material is independent of the structures damaged in amnesia.
Mem Cognit 1992 Jul
PMID:Nonverbal priming in amnesia. 149 6

Three experiments examined adult age differences in memory for new associations between unrelated words. On the indirect (word-stem completion) test, age differences appeared under the less-than-optimal study conditions of Experiments 1 and 3 but not under the self-paced study conditions of Experiment 2. In contrast, all experiments revealed significant age-related deficits on the direct tests, even those (word-stem cued recall) in which the cue was identical to those provided on the indirect test. The findings show that although age-related deficits in memory for new associations are particularly pronounced on tests requiring conscious recollection, age differences are not limited to such tests. Age deficits on both direct and indirect tests are related to the precision of elaborations produced during study. Similarities and differences between normal aging and amnesia are discussed, as are functional dissociations between direct and indirect measures.
J Exp Psychol Learn Mem Cogn 1991 Jul
PMID:Aging and memory for new associations: direct versus indirect measures. 183 36

The differences between learning in lorazepam (LOR)--or scopolamine (SCOP)--induced amnesia and learning in unaware drug-free normal subjects were examined. The drugs produced impairment in free recall, but did not affect digit span or word retrieval. In a verbal version, but not a motor version, of the serial reaction time task, the subjects who received SCOP or higher dose LOR showed impairment of sequence-specific learning. Subjects who received placebo had no such impairment. In the stem completion paradigm, higher dose LOR, but not SCOP, impaired performance. In a tachistoscopic word identification task, neither drug interfered with repetition priming. Unaware learning and drug-induced amnesic learning were thus dissociable. These findings disconfirm the hypothesis that unaware learning and drug-induced amnesic learning are analogous.
J Exp Psychol Learn Mem Cogn 1991 Sep
PMID:Unaware learning versus preserved learning in pharmacologic amnesia: similarities and differences. 183 65

Amnesic patients (n = 9) and normal subjects (n = 12) read lists of unique words, repeated words, unique nonwords, and repeated nonwords as quickly as possible. In the first experiment both groups of subjects read the lists of repeated items faster than the lists of unique items and improved at the same rate within each list. In the second experiment, subjects read four new lists of items and then reread the same four lists after a 10-min delay. The results replicated the findings from the first experiment and demonstrated in addition that the facilitated reading speed persisted across the delay. These results show that the acquisition of novel verbal information can be supported by nondeclarative (implicit) memory. It is suggested that facilitated reading speed for words and nonwords reflects changes in early-stage perceptual systems and that these changes occur independently of the brain structures damaged in amnesia.
J Exp Psychol Learn Mem Cogn 1991 Nov
PMID:Normal acquisition of novel verbal information in amnesia. 183 84

Repetition priming of novel stimuli (pseudowords) and stimuli with preexisting representations (words) was compared in two experiments. In one, 19 normal male subjects performed a lexical decision task with either focused or divided attention. In another, lexical decision performance was compared between 8 male Korsakoff patients and 8 alcoholic control subjects. In control conditions, repetition speeded responses to both stimulus types. Experimental conditions that minimized the contribution of episodic memory to task performance eliminated reaction time priming for pseudowords but not for words. However, in these same conditions, repetition increased the likelihood that pseudowords would be incorrectly classified. These results indicate that preserved repetition priming effects in amnesia do not solely reflect activation of representations in semantic memory.
J Exp Psychol Learn Mem Cogn 1990 Nov
PMID:Repetition priming of words and pseudowords in divided attention and in amnesia. 214 77

In a typical perceptual identification task, a word is presented for a few milliseconds and masked; then subjects are asked to report the word. It has been found that an earlier presentation of the test word will improve identification of the test word by as much as 30%. In addition, this facilitation has been shown to be preserved under amnesia. In this article we examine a fundamental question: Is the facilitation the result of bias toward the earlier presented item, an improvement in perceptual sensitivity, or both? The experiments presented here use a forced choice procedure to show that prior presentation of an item biases the subject to choose that item but does not improve discriminability. This result is obtained when the distractor items are visually similar to the target items. When distractors are dissimilar, earlier presentation affects neither bias nor discriminability. Two models of word identification are examined in light of the bias effects, and implications for understanding savings in amnesia are also examined.
J Exp Psychol Learn Mem Cogn 1989 May
PMID:A bias interpretation of facilitation in perceptual identification. 252 43

Although there is considerable agreement that performance in direct memory tasks (e.g., recall, recognition) is more disrupted by amnesia than performance in indirect memory tasks (e.g., mirror reading, word completion), one may be able to further circumscribe the deficit within the domain of direct memory tasks. The present article explores whether recall is disproportionately disrupted by amnesia compared to recognition. If amnesia affects memory uniformly across different direct memory measures, recall of normal controls should not differ from the recall of amnesics when recognition scores of these two groups are equated. On the other hand, if recall is disproportionately disrupted, normal recall should be superior to amnesic recall even when recognition is equated. The present study equated amnesic recognition with that of controls by providing amnesics with 8 s of study time and normal subjects with 0.5 s. Amnesics with Korsakoff's syndrome, amnesics with other etiologies, and appropriate controls were examined. Normal recall was superior to amnesic recall even when no differences were found in recognition. The results further specify the selective nature of amnesia.
J Exp Psychol Learn Mem Cogn 1986 Jul
PMID:Recognition and recall in amnesics. 294 28

Accuracy of the feeling of knowing was tested in patients with Korsakoff's syndrome, patients prescribed electroconvulsive therapy, four other cases of amnesia, and control subjects. In Experiment 1, we tested feeling-of-knowing accuracy for the answers to general information questions that could not be recalled. Subjects were asked to rank nonrecalled questions in terms of how likely they thought they would be able to recognize the answers and were then given a recognition test for these items. Only patients with Korsakoff's syndrome were impaired in making feeling-of-knowing predictions. The other amnesic patients were as accurate as control subjects in their feeling-of-knowing predictions. In Experiment 2, we replicated these findings in a sentence memory paradigm that tested newly learned information. The results showed that impaired metamemory is not an obligatory feature of amnesia, because amnesia can occur without detectable metamemory deficits. The impaired metamemory exhibited by patients with Korsakoff's syndrome reflects a cognitive impairment that is not typically observed in other forms of amnesia.
J Exp Psychol Learn Mem Cogn 1986 Jul
PMID:Memory and metamemory: a study of the feeling-of-knowing phenomenon in amnesic patients. 294 29

We investigated the ability of amnesic patients to learn new facts (e.g., Angel Falls is located in Venezuela) and also to remember where and when the facts were learned (i.e., source memory). To assess the susceptibility of fact and source memory to retrograde amnesia, patients prescribed electroconvulsive therapy were presented facts prior to the first treatment and were tested after their second treatment. All amnesic patients exhibited marked fact memory impairment. In addition, some amnesic patients exhibited source amnesia (i.e., they recalled a few facts but then could not remember where or when those facts had been learned). Source amnesia was unrelated to the severity of the memory deficit itself, because patients who exhibited source amnesia recalled as many facts as the patients who did not. These results show that the deficit in amnesia includes an impairment in acquiring and retaining new facts. Source amnesia can also occur, but it is dissociable from impaired recall and recognition and appears to reflect difficulty in remembering the specific context in which information is acquired. The findings are discussed in terms of their significance for how memory is organized.
J Exp Psychol Learn Mem Cogn 1987 Jul
PMID:A neuropsychological study of fact memory and source amnesia. 295 56


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