William P. Milberg

Lexical decision and aphasia: evidence for semantic processing.

Abstract Wernickes and Brocas-Conduction aphasics and a Global aphasic were presented with a lexical-decision task in which English words and pronounceable nonwords were preceded by semantically related, unrelated, or nonword primes. The patients were also given a simple semantic-judgment task using the word pairs from the lexical-decision task. Wernickes aphasics performed similar to normals and Brocas-Conduction aphasics showing significantly shorter latencies in making real-word identifications when preceded by a semantically related word. In addition, both superordinate and coordinate associates showed semantic-priming effects. Performance on the semantic-judgment task showed significantly more impairment in the aphasic group than in the normal controls. These results suggest that aphasics with even severe language impairments retain stored semantic information that may be automatically activated, yet is inaccessible to conscious semantic decision during metalinguistic tasks.

FALSE RECOGNITION AND THE RIGHT FRONTAL LOBE : A CASE STUDY

We described a patient, BG, who exhibited a striking pattern of false recognition after an infarction of the right frontal lobe. Seven experiments document the existence of the phenomenon, explore its characteristics, and demonstrate how it can be eliminated. BG showed pathologically high false alarm rates when stimuli were visual words (experiments 1 and 4), auditory words (experiment 2), environmental sounds (experiment 3), pseudowords (experiment 5), and pictures (experiment 7). His false alarms were not merely attributable to the semantic or physical similarity of studied and non-studied items (experiments 4 and 5). However, BGs false recognitions were virtually eliminated by presenting him with categorized stimuli and testing him with new stimuli from non-studied categories (experiments 6 and 7). The results suggest that BGs false alarms may be attributable to an over-reliance on memory for general characteristics of the study episode, along with impaired memory for specific items. The damaged right frontal lobe mechanisms may normally support the monitoring and/or retrieval processes that are necessary for item-specific recognition.

Semantic processing in aphasia: Evidence from an auditory lexical decision task☆

Abstract W. Milberg and S. E. Blumstein (1981, Brain and Language 14, 371–385) demonstrated semantic facilitation effects in a visual lexical decision task administered to Wernicke and other aphasics with severe comprehension deficits. In an attempt to explore the generalizability of these findings in a task where the acoustic-phonetic system could not be bypassed to access meaning, Wernickes, Global, Brocas, and Conduction aphasics were administered a lexical decision task in the auditory modality. The patients were also given a simple semantic judgment task using the word pairs from the lexical decision task. The aphasic patients showed evidence of semantic facilitation whether they were categorized by diagnostic group or comprehension level. Performance of the semantic judgment task correlated with the severity of auditory comprehension deficits, whereas the consistency of the semantic facilitation effect did not. Even patients with severe comprehension deficits showed semantic facilitation. These results decrease the likelihood that auditory comprehension deficits are due to semantic organization per se and increase the likelihood that the deficits lie in one of the many processes involved in access to that information.

Semantic processing in the neglected visual field: Evidence from a lexical decision task

Abstract The present study examined the possibility of a dissociation between visual information processing and conscious awareness of that processing in patients with unilateral visual neglect. Implicit processing of visual information was measured in the context of a semantic priming task (Experiment 1) in which patients made lexical decisions to centrally located targets following the presentation of lateralised picture primes. Like normal controls, patients with unilateral neglect showed equivalent priming when related picture primes were presented to the left or to the right visual field. This contrasts with the performance of a patient with a dense left hemianopia without neglect who did not show priming from the affected field.

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 subjects naming score.

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.

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 listeners 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.

Effect of Blood Pressure and Diabetes Mellitus on Cognitive and Physical Functions in Older Adults: A Longitudinal Analysis of the Advanced Cognitive Training for Independent and Vital Elderly Cohort

Objectives: To evaluate the effect of blood pressure (BP) and diabetes mellitus (DM) on cognitive and physical performance in older, independent‐living adults.

Cognitive Rehabilitation Interventions for Neglect and Related Disorders: Moving from Bench to Bedside in Stroke Patients

The spatial neglect syndrome, defined by asymmetric attention and action not attributed to primary motor or sensory dysfunction and accompanied by functional disability, is a major cause of post-stroke morbidity. In this review, we consider the challenges and obstacles facing scientific researches wishing to evaluate the mechanisms and effectiveness of rehabilitation interventions. Spatial neglect is a heterogeneous disorder, for which consensus research definitions are not currently available, and it is unclear which of the deficits associated with the syndrome causes subsequent disability. We review current opinion about methods of assessment, suggest a rational approach to selecting therapies which requires further study, and make systems-level and theoretical recommendations for building theory. We lastly review some creative questions for consideration in future research.

Cognitive function in normal-weight, overweight, and obese older adults : An analysis of the advanced cognitive training for independent and vital elderly cohort

Objectives: To assess how elevated body mass index (BMI) affects cognitive function in elderly people.