Amnesic patients often exhibit spared priming effects on implicit memory tests despite poor explicit memory. In previous research, we found normal auditory priming in amnesic patients on a task in which the magnitude of priming in control subjects was independent of whether speaker's voice was same or different at study and test, and found impaired voice-specific priming on a task in which priming in control subjects is higher when speaker's voice is the same at study and test than when it is different. The present experiments provide further evidence of spared auditory priming in amnesia, demonstrate that normal priming effects are not an artifact of low levels of baseline performance, and provide suggestive evidence that amnesic patients can exhibit voice-specific priming when experimental conditions do not require them to interactively bind together word and voice information. (JINS, 1995, I, 434–442.)

Efficient solution of the Tower of London (T of L) test (Shallice, 1982) has been hypothesized to depend on frontal lobe mediation. Performance on the test by 20 patients with severe, diffuse, traumatic head injury was compared with that of control subjects, matched on age and years of education, and, within the patient group, according to broad location of damage (frontal or nonfrontal). Scores were also compared with those obtained on two commonly used tests of frontal lobe function, Verbal Fluency, and the Wisconsin Card Sorting test (WCST). Results indicated that whereas the Verbal Fluency test and WCST discriminated well between patients and control subjects, the T of L test did not, nor did it discriminate well between patients with and without documented frontal lobe damage. However, there were large individual differences in planning and solution times across all subjects. Interpretation of results was complicated by interaction of other variables such as premorbid IQ and duration of posttraumatic amnesia. It is suggested that closer attention to the relation between planning and total times separately for correct and incorrect solutions might be informative. A need for systematic study of the relationship between test performance and everyday behavior is also identified. (JINS, 1995, 7, 537–544.)

Two new tasks designed to individualize and assess aspects of cognitive flexibility and complex integration were administered to patients with schizophrenia (n = 16), Parkinson's disease (PD; n = 25) and Huntington's disease (HD; n = 12). Findings indicated impaired performance in the schizophrenic and HD groups on components of solution fluency, reactive flexibility and integration. The PD group demonstrated normal performance on all but the solution fluency and reaction time measures. These findings corroborate previous studies suggesting that executive and problem solving disturbances feature in schizophrenia and HD and that these functions may not be as severely affected in medicated PD. Slowed reaction time by both dementia groups is explained with reference to the concept of bradyphrenia. (JINS, 1995, 1, 545–553.)

Neuropathology in Huntington's disease (HD) known to project to areas that process olfactory information raises the questions of which olfactory function, if any, is most affected in HD, and how to explain such dysfunction in terms of olfactory sensitivity and cognition. These questions were studied by comparing HD patients and controls (matched for age, gender, and education) on absolute detection, intensity discrimination, quality discrimination, short-term recognition memory, and lexical- and picture-based identification for odor. Taste or vision were used as comparison modalities. The results suggest that whereas odor-recognition memory is not affected in patients with HD, these patients have impaired olfactory functioning with respect to absolute detection, intensity discrimination, quality discrimination, and identification. The three latter impairments were significantly explained by poor detection sensitivity. Odor identification was the function most affected. (JINS, 1995, I, 281–290.)

The purpose of this study was to compare a mnemonic strategy based on concept-driven processing and explicit memory (i.e., verbal elaboration and imagery) to one based on data-driven processing and implicit memory (the method of vanishing cues) in a names and faces learning task. A third training condition that used video presentation was also included. Six American and six German patients with memory impairment attributable to brain injuries of different etiologies attempted to learn the associations between names and faces in each of the three conditions. The mnemonic strategy proved to be the most effective. Discussion focuses on the characteristics of the training procedures and on the nature of the to-be-learned materials as critical determinants of the effectiveness of different training techniques. (JINS, 1995, 1, 29–38.)

To assess if amnesics have intact remote memory for general semantic information, we examined memory for vocabulary words with known dates of entry into the language between 1955 and 1989. Amnesics of mixed etiology with acute onset performed normally on both a recall and a recognition task. Korsakoff patients, in contrast, were impaired on both tasks and demonstrated a gradient such that their knowledge of words acquired during more recent time periods was worse than that of words acquired during more remote time periods. The improvement in performance associated with recognition testing was larger for Korsakoff patients than for control subjects and correlated significantly with a composite measure of frontal dysfunction. These findings suggest a deficit in the controlled search and retrieval of semantic information in Korsakoff patients. The implications of the differential performance of Korsakoff and mixed etiology amnesics for explanations of temporally graded retrograde amnesia are discussed. (JINS, 1995, I, 443–453.)

Several studies of semantic abilities in Dementia of the Alzheimer Type (DAT) suggest that their semantic disorders may affect specific categories of knowledge. In particular, the existence of a category-specific semantic impairment affecting, selectively, living things has frequently been reported in association with DAT. We report here results from two naming tasks of 25 DAT patients and two subgroups within this population. The first naming task used 48 black and white line drawings from Snodgrass and Vanderwart (1980) which controlled the visual complexity of stimuli from living and nonliving categories. The second task used 44 colored pictures (to assess the influence of word frequency in living vs. nonliving categories). Within the set of black and white pictures, both DAT patients and controls obtained significantly lower scores on high visual complexity stimuli than on stimuli of low visual complexity. A clear effect of semantic category emerged for DAT patients and controls, with a lower performance on the living category. Within the colored set, pictures corresponding to high frequency words gave rise to significantly higher scores than pictures corresponding to low frequency words. No significant difference emerged between living versus nonliving categories, either in DAT patients or in controls. In the two tasks, the two subgroups of DAT patients presented a different profile of performance and error type. As color constitutes the main difference between the two sets of pictures, our results point to the relevance of this cue in the processing of semantic information, with visual complexity and frequency also being very relevant. (JINS, 1995, I, 39–48.)

Hypoxia is known to cause damage to the hippocampus as well as memory impairments in humans. Subjects who have experienced a hypoxic episode and age-, gender-, and education-matched control subjects were tested for memory for spatial and linguistic temporal distance information using sentences and spatial locations. Each test contained a familiar component based on information that is meaningful and is thought to be stored as part of the knowledge system (prior knowledge) as well as a novel component based on new information. Subjects were presented a list of eight-word sentences or eight spatial locations (Xs) on a grid on a Macintosh computer and tested for memory for temporal distances. Temporal distance is defined as the number of items that occur between the two test items, in the study phase. Compared to control subjects, hypoxic subjects were impaired across all temporal distances on the novel spatial and linguistic tasks. As the temporal distance increased, hypoxic subjects showed some improvement in memory performance. In addition, memory of familiar temporal distance information was also assessed. Hypoxic subjects were impaired, compared to control subjects, for familiar temporal distance information. For hypoxic subjects there was a proportionally greater impairment for novel compared to familiar spatial and linguistic temporal distance information. There was a significant difference in their performance on the familiar temporal distance tasks compared to their performance on the novel tasks. Prior knowledge appears to attenuate the deficits seen in the familiar temporal distance tasks. It appears that hypoxia may cause more selective damage to the hippocampus and this damage is sufficient to produce profound memory impairments for primarily novel and less severe memory impairments for familiar spatial and linguistic temporal distance information. (JINS, 1995, I, 454–468.)

Forty-eight patients with temporal lobe epilepsy completed measures of narrative recall and list learning prior to surgery. The intracarotid amytal procedure (IAP) established that 13 patients were right hemisphere dominant for speech and 35 (18 left foci, 17 right foci) were left hemisphere dominant. Hippocampal volumetric neuron densities were measured after surgery. The left hippocampal neuron densities in subfields CA3 and the hilar area were significantly correlated with list learning ability and percent retention for narrative recall only for left hemisphere speech dominant patients with left seizure foci. No significant correlations between measures of neuron volume and memory were found for the left hemisphere speech dominant patients with right seizure foci or the right hemisphere speech dominant patients with left seizure foci. This suggests that the right hemisphere of right speech dominant patients mediates verbal memory as well as speech. This conclusion is supported by patterns of correlations among measures of verbal memory that differed for patients undergoing resection of the dominant hemisphere versus those undergoing resection of the nondominant hemisphere. However, it is premature to conclude that the cerebral organization of cognitive functions of right hemisphere speech dominant patients is equivalent albeit reversed from that of left hemisphere speech dominant patients. Right hemisphere speech dominant patients with left temporal foci differed from left hemisphere speech dominant patients with right temporal foci with respect to the patterns of correlations between measures of verbal memory and intelligence as well as the level of intellectual ability that they demonstrated. (JINS, 1995, 1, 554–560.)

We administered the Multiscale Depression Inventory (MDI) and the Beck Depression Inventory (BDI) to 84 multiple sclerosis (MS) patients, 101 patients diagnosed with major depression and 87 nonmedical, nonpsychiatric controls. The MDI consists of three separate depression scales measuring mood, vegetative, and evaluative symptoms. We found that: (a) MS patients did not significantly differ from the controls in mood symptoms, (b) the depression prevalence rate in MS patients was significantly lower when measured by the mood scale (17·7%) than by the BDI (30·5%) or MDI total score (26·6%), and (c) MS patients showed significantly less mood disturbance than a non-MS comparison group matched on BDI measured depression severity. We suggest that the inclusion of nonmood symptoms in self-report depression scales may artificially raise both prevalence rates and severity ratings of MS related depression and that the most valid measure of depression in MS is mood disturbance. (JINS, 1995, I, 291–296.)

To examine the contribution of memory deficits and executive dysfunction to the production of prior-item intrusion errors, Korsakoff, mesial temporal amnesic, and anterior communicating artery aneurysm (ACoA) patients’ performance on the Visual Reproduction subtest of the Wechsler Memory Scale-Revised (WMS-R) was assessed. The Korsakoff patients were matched to the mesial temporal group in terms of severity of amnesia, while the ACoA group, which was less severely amnesic, was matched to the Korsakoff group in their performance on executive tests. Results indicated that at immediate recall, Korsakoff patients made significantly more intrusions than mesial temporal and ACoA patients. Conversely, after a delay, ACoA patients tended to make more intrusions than the other groups. Findings suggest that intrusions are due to a combination of deficient memory and executive dysfunction. A further comparison of a subgroup of ACoA patients matched to the Korsakoff patients in terms of severity of amnesia, however, revealed differences in the pattern of intrusions of these two groups, suggesting that different mechanisms may underlie Korsakoff and ACoA patients’ susceptibility to interference. (JINS, 1995, 1, 561–567.)

It has been postulated that rehearsal rate is the primary determinant of working memory capacity for verbal material (Baddeley et al., 1975). A previous study of normal control children and children with spastic diplegic cerebral palsy (SDCP) suggested that covert rather than overt rehearsal rate determines working memory capacity (White et al., 1994). In the current study, a subset of SDCP children who received a surgical treatment to relieve spasticity were retested on measures of articulation rate and memory span. A subset of control children from the original study were also retested. The SDCP group showed improvements in articulation rate at follow-up, though memory span did not change and was again equivalent to that of controls. These findings indicate that increases in articulation rate are not necessarily accompanied by improvements in memory span, and provide additional evidence that working memory capacity may be determined by covert rather than overt articulatory rehearsal. (JINS, 1995, I, 49–55.)