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Biomedical subjects

W Milberg

Publications and source records attributed to W Milberg.

16 recordsLinked to original sources
PubMed1991

A further analysis of perceptual identification priming in alcoholic Korsakoff patients.

Alcoholic Korsakoff patients have been shown to have normal repetition priming for words, but impaired priming for pseudowords, on perceptual identification tasks. Because real words, but not pseudowords, have semantic representations, successful priming of real words has been attributed to semantic activation. Alternatively, however, priming might reflect the perceptual, i.e. orthographic and phonological familiarity associated with real words in comparison with pseudowords. In order to examine which of these factors accounts for normal priming by amnesics, Experiment 1 was designed to contrast perceptual identification priming for words, pseudowords and pseudohomonyms (e.g. "phaire"). On this task, Korsakoff patients showed normal priming for real words and for pseudohomonyms, but significantly impaired priming for pseudowords. It was felt that since pseudohomonyms are orthographically unfamiliar but could access semantics through their phonological route, activation of a semantic representation rather than perceptual familiarity might be the critical factor underlying successful priming. Experiment 2 was then designed to further explore the robustness of this semantically mediated priming by presenting different word types within the same study list. Under these conditions, Korsakoffs' pseudohomonym priming was consistently below normal. This suggests that priming in Korsakoff patients depends upon the conceptual salience of the stimuli and not solely on semantic activation.

Alcohol Amnestic Disorder↗
PubMed1990

Intact priming of patterns despite impaired memory.

The priming of patterns was examined in normal control subjects (NCS) and in the amnesic patient H.M., whose anterograde amnesia followed bilateral medial temporal-lobe excision 33 years earlier. Despite H.M.'s impaired recognition of the patterns, he demonstrated a pattern priming effect equivalent in magnitude to that of the NCS. The results demonstrated that intact priming with novel, nonverbal material can occur despite severe amnesia. Pattern priming may reflect adaptive visual processes involved in learning novel perceptual organizations of known visual codes, such as letters, words, shapes, and objects.

Amnesia↗
PubMed1989

Reaction time methodology and the aphasic patient: a reply to Hagoort (1988).

P. Hagoort (1988, Brain and Language, 36, 335-348) suggests that the results of an experiment conducted with aphasic patients reported by W. Milberg, S. E. Blumstein, and B. Dworetzky (1987, Brain and Language, 31, 138-150) are "difficult to interpret in terms of a selective access model for normal processing because of a confound caused by the use of repeated lexical decision targets." We argue that the use of repeated lexical decision targets and other methodological compromises are necessary for using the lexical decision reaction time paradigm with aphasic patients. Furthermore, the minor differences between our data and those presented by Hagoort do not undermine our claims concerning semantic processing in different subgroups of aphasics, nor our comparisons of these patients to normal subjects.

Aphasia↗
PubMed1989

Semantic processing in patients with Alzheimer's disease.

Ten patients with dementia of the Alzheimer type and 10 normal controls performed a lexical decision, semantic facilitation task. The performance of the patients differed from that seen in normals. A post hoc subdivision of the data suggested that the diviation from normality was not uniform throughout the patient population. Six of the 10 Alzheimer patients showed an advantage of related primes over unrelated primes, while 4 of the 10 were actually faster in the unrelated condition than in the related condition. Nevertheless, both group of Alzheimer patients showed lexical decision latency differences between unrelated and related prime words, suggesting that patients with Alzheimer's disease are sensitive to the semantic relationships between words.

Aged↗
PubMed1989

Cognitive differences between patients with progressive supranuclear palsy and Alzheimer's disease.

Sixteen patients with dementia of the Alzheimer type (AD) and nine patients with Progressive Supranuclear Palsy (PSP) were administered a battery of neuropsychological tasks that assessed a cross-section of cognitive abilities. The subjects were equated in terms of overall level of impairment. There was no difference between the groups on the WAIS subtests that were administered (Vocabulary, Digit Span Forward, Similarities, Block Design). There was a striking difference between the AD and PSP patients on tests of verbal and nonverbal memory, as assessed by the Wechsler Memory Scale. The memory performance of the PSP patients did not, in fact, differ from a group of normal controls. In addition, there was a double-dissociation between the AD and PSP patients on tasks that evaluated naming and verbal fluency.

Aged↗
PubMed1988

Phonological processing and lexical access in aphasia.

This study explored the relationship between on-line processing of phonological information and lexical access in aphasic patients. A lexical decision paradigm was used in which subjects were presented auditorily with pairs of words or word-like stimuli and were asked to make a lexical decision about the second stimulus in the pair. The initial phonemes of the first word primes, which were semantically related to the real word targets, were systematically changed by one or more than one phonetic feature, e.g., cat-dog, gat-dog, wat-dog. Each of these priming conditions was compared to an unrelated word baseline condition, e.g., nurse-dog. Previous work with normals showed that even a nonword stimulus receives a lexical interpretation if it shares a sufficient number of phonetic features with an actual word in the listener's lexicon. Results indicated a monotonically decreasing degree of facilitation as a function of phonological distortion. In contrast, fluent aphasics showed priming in all phonological distortion conditions relative to the unrelated word baseline. Nonfluent aphasics showed priming only in the undistorted, related word condition relative to the unrelated word baseline. Nevertheless, in a secondary task requiring patients to make a lexical decision on the nonword primes presented singly, all aphasics showed phonological feature sensitivity. These results suggest deficits for aphasic patients in the various processes contributing to lexical access, rather than impairments at the level of lexical organization or phonological organization.

Adult↗
PubMed1988

Learning of a complex arithmetic skill in amnesia: evidence for a dissociation between compilation and production.

Two patients with severe amnesia following rupture of anterior communicating artery aneurysms were able to learn a complex algorithm for mentally squaring two-digit numbers. Although both patients learned the algorithm at a similar rate, one patient's improvement was accounted for by savings in the steps of the algorithm. The other patient, however, showed little improvement in the steps while performance of the whole algorithm improved dramatically. Neither patient showed savings in the Hebb Digit Span procedure. The results suggested a dissociation between amnesics in their capacity to learn the constituent "productions" or steps of a skill and their capacity to organize those productions into a single coherent act.

Adult↗
PubMed1988

Teaching an amnesic a complex cognitive skill.

G.P., a Korsakoff's amnesic, was able to learn an algorithm for squaring two-digit numbers mentally over a 7-day period at a rate comparable to that of age-matched controls. He failed to show normal positive transfer to specific problems or to specific numbers used in components of the task. He also exhibited slight improvement in simple naming speed, forward digit span, simple multiplication speed, but no apparent improvement for the recall of repeated supraspan digit strings. He was unable to state the algorithm he had learned to square two-digit numbers, though he could implement it successfully. The results suggest that the compilation of a skill may involve two dissociable components: composition and proceduralization, with the former, but not the latter, occurring at normal rates for Korsakoff's amnesics.

Aged↗
PubMed1988

Changes in naming ability with age.

We administered to 80 optimally healthy subjects, 30-80 years old, the Boston Naming Test, a test of confrontation naming. Results indicated that naming ability remains fairly stable across the adult life span until individuals are in their 70s, at which point there is a significant decline in performance (p less than or equal to .0001). Semantic errors (i.e., circumlocutions, semantically related associates, and nominalizations) and perceptual errors increase with age. Lexical errors (i.e., phonologically related real words and phonologically related nonwords) do not increase with age. Results of multiple regressions that included other neuropsychological variables indicate that estimated IQ, but not new learning ability, predicts a subject's naming score.

Adult↗
PubMed1987

Processing of lexical ambiguities in aphasia.

Wernicke's and Broca's aphasics performed a lexical decision task wherein they had to decide whether the third word of an auditorily presented triplet series of words was "real" or not. The first and third words of each triplet were related to one, both, or neither meaning of the second word which was semantically ambiguous. The performance pattern of the Wernicke's aphasics was similar to that of normals. They showed selective access to different meanings of the ambiguous words, as demonstrated by the fact that the context provided by the first word affected semantic facilitation on the third word. In contrast, Broca's aphasics showed no semantic facilitation in any priming condition. These results are consistent with previous findings, suggesting that semantic representations may be largely spared in Wernicke's aphasics. The failure of the Broca's aphasics to demonstrate facilitation is consistent with the view that they have a processing deficit in automatically accessing the lexical representation of words.

Aged↗
PubMed1987

Radial localization in the aged.

Elderly subjects were 41% less accurate than young subjects in localizing a point in the frontal plane. The decline could be ascribed neither to an age difference in image formation or skill acquisition nor to a difference in motivational level or trace retention. Evidently the "ambient" or "transient" visual system is compromised at an elementary level. Reasons why this deficit may not be compounded at more complex levels of spatial processing are suggested.

Adult↗