Showing papers on "Verbal learning published in 1999"
TL;DR: Patients who meet the criteria for MCI can be differentiated from healthy control subjects and those with very mild AD, and appear to constitute a clinical entity that can be characterized for treatment interventions.
Abstract: Background Subjects with a mild cognitive impairment (MCI) have a memory impairment beyond that expected for age and education yet are not demented. These subjects are becoming the focus of many prediction studies and early intervention trials. Objective To characterize clinically subjects with MCI cross-sectionally and longitudinally. Design A prospective, longitudinal inception cohort. Setting General community clinic. Participants A sample of 76 consecutively evaluated subjects with MCI were compared with 234 healthy control subjects and 106 patients with mild Alzheimer disease (AD), all from a community setting as part of the Mayo Clinic Alzheimer's Disease Center/Alzheimer's Disease Patient Registry, Rochester, Minn. Main Outcome Measures The 3 groups of individuals were compared on demographic factors and measures of cognitive function including the Mini-Mental State Examination, Wechsler Adult Intelligence Scale–Revised, Wechsler Memory Scale–Revised, Dementia Rating Scale, Free and Cued Selective Reminding Test, and Auditory Verbal Learning Test. Clinical classifications of dementia and AD were determined according to the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition and the National Institute of Neurological and Communicative Disorders and Stroke–Alzheimer's Disease and Related Disorders Association criteria, respectively. Results The primary distinction between control subjects and subjects with MCI was in the area of memory, while other cognitive functions were comparable. However, when the subjects with MCI were compared with the patients with very mild AD, memory performance was similar, but patients with AD were more impaired in other cognitive domains as well. Longitudinal performance demonstrated that the subjects with MCI declined at a rate greater than that of the controls but less rapidly than the patients with mild AD. Conclusions Patients who meet the criteria for MCI can be differentiated from healthy control subjects and those with very mild AD. They appear to constitute a clinical entity that can be characterized for treatment interventions.
8,255 citations
TL;DR: Atypical antipsychotic drugs as a group appear to be superior to typical neuroleptics with regard to cognitive function, however, available data suggest that these drugs produce significant differences in specific cognitive functions.
Abstract: Cognitive function is markedly impaired in most patients with schizophrenia. Antecedents of this impairment are evident in childhood. The cognitive disability is nearly fully developed at the first episode of psychosis in most patients. The contribution of cognitive impairment to outcome in schizophrenia, especially work function, has been established. Preliminary results indicate that cognitive function, along with disorganization symptoms, discriminate schizophrenia patients who are able to work full-time from those who are not. Typical neuroleptic drugs lack the ability to improve the various domains of cognitive function impaired in schizophrenia. Atypical antipsychotic drugs pharmacologically related to clozapine-quetiapine, olanzapine, risperidone, sertindole, and ziprasidone--share the ability to produce fewer extrapyramidal symptoms than typical neuroleptic drugs and more potent antagonism of serotonin2a relative to dopamine2 receptors. However, they have a number of different clinical effects. We have identified all the studies of clozapine, olanzapine, and risperidone that provide data on their effects on cognition in schizophrenia. Data for each drug are reviewed separately in order to identify differences among them in their effects on cognition. Twelve studies that report cognitive effects of clozapine are reviewed. These studies provide (1) strong evidence that clozapine improves attention and verbal fluency and (2) moderate evidence that clozapine improves some types of executive function. However, results of the effects of clozapine on working memory and secondary verbal and spatial memory were inconclusive. Risperidone has relatively consistent positive effects on working memory, executive functioning, and attention, whereas improvement in verbal learning and memory was inconsistent. Preliminary evidence presented here suggests that olanzapine improves verbal learning and memory, verbal fluency, and executive function, but not attention, working memory, or visual learning and memory. Thus, atypical antipsychotic drugs as a group appear to be superior to typical neuroleptics with regard to cognitive function. However, available data suggest that these drugs produce significant differences in specific cognitive functions. These differences may be valuable adjunctive guides for their use in clinical practice if cognitive improvements reach clinical significance. The effects of the atypical antipsychotic drugs on cholinergic and 5-HT2a-mediated neurotransmission as the possible basis for their ability to improve cognition are discussed. It is suggested that the development of drugs for schizophrenia should focus on improving the key cognitive deficits in schizophrenia: executive function, verbal fluency, working memory, verbal and visual learning and memory, and attention.
1,032 citations
TL;DR: It was concluded that phonological recoding is critical to the acquisition of word-specific orthographic representations as proposed by the self-teaching hypothesis.
689 citations
TL;DR: This work examined word-recognition memory in patients enrolled in a clinical study evaluating the capacity of vagus nerve stimulation to control epilepsy and found Stimulation administered after learning significantly enhanced retention.
Abstract: Neuromodulators associated with arousal modulate learning and memory, but most of these substances do not freely enter the brain from the periphery. In rodents, these neuromodulators act in part by initiating neural messages that travel via the vagus nerve to the brain, and electrical stimulation of the vagus enhances memory. We now extend that finding to human verbal learning. We examined word-recognition memory in patients enrolled in a clinical study evaluating the capacity of vagus nerve stimulation to control epilepsy. Stimulation administered after learning significantly enhanced retention. These findings confirm in humans the hypothesis that vagus nerve activation modulates memory formation similarly to arousal.
527 citations
TL;DR: The results suggest that individuals with an autism spectrum condition are impaired in achieving local coherence, and they have a preference not to strive for coherence unless instructed to do so, or unless they make a conscious decision toDo so.
434 citations
TL;DR: It is concluded that the HVLT-R is a valid test of verbal learning and memory that is best suited for use with elderly patients suspected of dementia.
Abstract: The present investigation examined the validity of the revised Hopkins Verbal Learning Test (HVLT-R). In a principal components analysis with varimax rotation, measures of new learning and delayed ...
382 citations
TL;DR: It is concluded that stimulation of the subthalamic nucleus or internal globus pallidus does not change the overall cognitive performance in Parkinson's disease and does not greatly affect the functioning of subcorticofrontal loops involved in cognition in humans.
Abstract: There is a renewal of interest in surgical approaches including lesions and deep brain stimulation directed at motor subcorticofrontal loops. Bilateral lesioning presents a far greater risk of adverse effects, especially cognitive impairment. Furthermore, the main advantages of the stimulation procedure over lesioning are adaptability and reversibility of effects. The aim of this study was to assess the influence of bilateral stimulation of the subthalamic nucleus or internal globus pallidus on memory and executive functions in Parkinson's disease. Sixty-two patients were assessed before and after 3 to 6 months of chronic bilateral stimulation of the subthalamic nucleus (n = 49) or internal globus pallidus (n = 13). The neuropsychological tests used were the Mattis Dementia Rating Scale, the Grober and Buschke Verbal Learning Test, the Wisconsin Card Sorting Test, category and literal fluency, graphic and motor series, the Stroop Test, and the Trail Making Test. Mood was evaluated by the Beck Depression Inventory. Only 4 of 25 cognitive variables were affected by deep brain stimulation. Under stimulation, performance improved for Parts A and B of the Trail Making Test, but there was a deterioration in literal and total lexical fluency. There was also a mild but significant improvement in mood. It may therefore be concluded that stimulation of the subthalamic nucleus or internal globus pallidus does not change the overall cognitive performance in Parkinson's disease and does not greatly affect the functioning of subcorticofrontal loops involved in cognition in humans. This relative absence of cognitive impairment in bilateral deep brain stimulation is likely because of the accurate positioning of the electrodes, allowing the effects of stimulation to be confined to sensorimotor circuits.
374 citations
TL;DR: Gender and two NBTs can help predict PCS after MHI, and no variables fit the model at 6 months.
Abstract: Objective : To determine if clinical variables or neurobehavioural test (NBT) scores obtained in the ED within 24 hours of minor head injury (MHI) predict the development of postconcussive syndrome (PCS). Methods : Prospective, observational study of 71 MHI patients and 60 orthopaedic controls. MHI defined as loss of consciousness < 10 minutes or amnesia, GCS 15, no skull fracture or new neurologic focality on PE, and no brain injury on CT (if done). All patients received a seven part NBT battery in the ED. Telephone follow-up was done at 1, 3 and 6 months to determine if patients met the DSM IV definition of PCS. Analysis : Stepwise, multivariate, logistic regression. Results : Predictors of PCS at 1 month were female gender (OR 7.8; 95% CI 41.6, 1.98), presence of both retrograde and anterograde amnesia (OR 0.055; CI 0.002, 0.47), Digit Span Forward Scores (OR 0.748; CI 0.52, 1.03) and Hopkins Verbal Learning A scores (OR 0.786; CI 0.65, 0.91); at 3 months, presence of both retrograde and anterograde...
316 citations
TL;DR: Exercising in a virtual environment offers the potential for significant gains in cognitive function after a 4-week intervention program and significant improvements in reaction times and movement times were gained following a single bout of VR exercise.
300 citations
TL;DR: It is concluded that tryptophan depletion specifically impairs long-term memory formation, presumably as a result of an acute decrease in 5-HT turnover in the brain.
Abstract: Serotonin (5-hydroxytryptamine; 5-HT) circuits may play a role in cognitive performance, particularly in learning and memory. Cognitive impairment is often seen in depressed patients, in whom 5-HT turnover in the brain is thought to be lowered. A possible human pharmacological model to study the involvement of the serotonergic system in cognitive impairment is to reduce central 5-HT synthesis through L-tryptophan depletion in healthy subjects. In this study, the cognitive effects of tryptophan depletion were assessed and whether genetically or developmentally determined vulnerability factors were predictive of the cognitive impairment induced by tryptophan depletion. Sixteen healthy volunteers with a positive family history of depression and 11 without were given 100 g of an amino acid mixture with or without tryptophan, according to a double-blind, cross-over design. Tryptophan depletion specifically impaired long-term memory performance in all subjects: delayed recall performance, recognition sensitivity, and recognition reaction times were significantly impaired after tryptophan depletion relative to placebo. Short-term memory and perceptual and psychomotor functions were unchanged. There were no differences between groups with a positive and a negative family history for depression. On the basis of these results, it is concluded that tryptophan depletion specifically impairs long-term memory formation, presumably as a result of an acute decrease in 5-HT turnover in the brain.
277 citations
TL;DR: Verbal memory and reaction performance were not impaired, and there was even a statistically significant time x group interaction with improvement of verbal memory performance after fast rTMS, which further supported the safety of rT MS but does not show any clinically meaningful antidepressant efficacy.
Abstract: In previous studies, fast repetitive transcranial magnetic stimulation (rTMS) with a frequency >1 Hz demonstrated substantial antidepressant effects compared to sham rTMS. However, it is not clear whether fast rTMS is superior to slow rTMS (frequency ≤1 Hz) which is safe at therapeutically promising higher intensities. The aim of this double-blind study was to compare the action of fast, slow and sham rTMS. Eighteen patients with pharmacotherapy-resistant major depression were randomized to receive fast (10 Hz), slow (0.3 Hz) or sham rTMS with 250 stimuli/day for 5 successive days. rTMS was applied at 90% motor threshold intensity to the left dorsolateral prefrontal cortex. Scores on the Hamilton Depression Rating Scale (HDRS), but not on the Montgomery–Asberg Depression Rating Scale (MADRS), showed a statistically significant time×group interaction with a reduction of 19% after slow rTMS. However, the effect was clinically marginal and not reflected by self-rating scores. Verbal memory and reaction performance were not impaired after rTMS, and there was even a statistically significant time×group interaction with improvement of verbal memory performance after fast rTMS. In conclusion, this study further supported the safety of rTMS but does not show any clinically meaningful antidepressant efficacy of rTMS at 250 daily stimuli over 5 days in pharmacotherapy-refractory major depression.
TL;DR: This article investigated whether working-memory span differences across age are attributable to specific or general processing functions and found that significant performance differences remained among age groups on gain and maintenance conditions, and that the gain (accessing new information) and maintenance condition (maintenance of old information) for verbal and visuospatial WM tasks contributed independent variance to agerelated performance.
Abstract: This study investigated whether working-memory (WM) span differences across age are attributable to specific or general processing functions. The study compared 9 age groups (6, 8, 10, 13, 16, 24, 35, 45, 57 years) on verbal and visuospatial WM performance under initial (no probes or cues), gain (cues that bring performance to an asymptotic level), and maintenance conditions (asymptotic conditions without cues). (a) Age-related performance differences in WM were found across all conditions and were not isolated to specific processes, (b) significant performance differences remained among age groups on gain and maintenance conditions, and (c) the gain (accessing new information) and maintenance conditions (maintenance of old information) for verbal and visuospatial WM tasks contributed independent variance to age-related performance. The results support a general capacity explanation of age-related differences. These differences in capacity reflect demands placed on both the accessing of new information and the maintenance of old information.
TL;DR: Compared thalamic size, shape, and metabolic activity in unmedicated patients with schizophrenia and schizotypal personality disorder to findings in age- and sex-matched healthy control subjects, schizophrenic patients showed significant metabolism and shape differences from control subjects in selective subregions of the thalamus.
Abstract: OBJECTIVE: In an exploration of the schizophrenia spectrum, the authors compared thalamic size, shape, and metabolic activity in unmedicated patients with schizophrenia and schizotypal personality disorder to findings in age- and sex-matched healthy control subjects. METHOD: Coregistered magnetic resonance imaging (MRI) and positron emission tomography scans were obtained in 27 schizophrenic patients, 13 patients with schizotypal personality disorder, and 32 control subjects who performed a serial verbal learning test during tracer uptake. After thalamus edges were outlined on 1.2-mm MRI scans, a radial warping program yielded significance probability mapping in three dimensions. RESULTS: Significance probability mapping (with resampling) identified an area in the region of the mediodorsal nucleus bilaterally with significantly lower relative metabolism in the schizophrenia group than in either the control or schizotypal personality disorder groups, which did not differ from each other. The three groups d...
TL;DR: Although the demented PD (PDD) group performed significantly more poorly than their non-demented counterparts and normal controls on all three fluency tasks, a disproportionate disparity in scores was noted on the action fluency task.
Abstract: Previous research suggests that lexical and semantic verbal fluency are differentially sensitive to the effects of cortical and subcortical dementias, but little is known about action fluency performance in dementias. The present study compared lexical, semantic, and action fluency in groups of patients with Parkinson's disease (PD) with and without dementia and an elderly control group. Findings revealed an interaction between fluency type and subject group. Although the demented PD (PDD) group performed significantly more poorly than their non-demented counterparts and normal controls on all three fluency tasks, a disproportionate disparity in scores was noted on the action fluency task. The findings suggest that action fluency may be particularly sensitive to PD-associated dementia and may be an early indicator of the conversion from PD to PDD. As reported elsewhere, PD without dementia was not associated with significant impairment on any of the fluency tasks.
TL;DR: The results are interpreted as showing the possible influence of formal learning to read and write, on the biological development of the brain.
Abstract: Variations in the individual anatomy of the corpus callosum have been reported in several conditions. There seem to be genetic influencing factors, but it is impossible to rule out some environmental ones. This study focuses on the question of the environmental factors, using formal learning to read and write as the main difference in the groups to be compared. Based on magnetic resonance imaging sagital images, the contour of the corpus callosum (CC) of 41 carefully selected women (18 illiterate and 23 literate) was digitized. The comparison between the two groups showed a small difference in the region of the CC where parietal fibres are thought to cross. This region is thinner in illiterate subjects. As illiteracy in this group is the result of social constraints, and the two groups that were compared are well matched for other cultural and pragmatic aspects than literacy, the results are interpreted as showing the possible influence of formal learning to read and write, on the biological development of the brain.
TL;DR: The patients with less severe injuries performed significantly poorer on the WMT measures of biased responding, and were divided into two groups, those with relatively mild head injuries and those with moderate or severe brain injuries.
Abstract: The Word Memory Test (WMT) is a relatively new computer-based test that is designed to measure both verbal memory and biased responding (i.e. malingering). The purpose of this study was to examine the performance of a large sample of patients involved in head injury litigation on the WMT measures of biased responding. The patients were divided into two groups, those with relatively mild head injuries (n = 234) and those with moderate or severe brain injuries (n = 64). The patients with less severe injuries performed significantly poorer on the WMT measures of biased responding.
TL;DR: The neuropsychological functions of children with VCFS are explored in greater depth to rule out NLD, since they may benefit from specific remediation following the learning principles of the NLD-treatment.
Abstract: In this exploratory study, the neuropsychological and learning profile of nine primary school age children with velo-cardio-facial syndrome (VCFS) was studied by systematic neuropsychological testing. In five out of nine children, the following profile was found: a VIQ-PIQ discrepancy (in favor of the VIQ), significantly better scores (.05 level) for reading (decoding) and spelling compared to arithmetic, deficient tactile-perceptual skills (difficulties mainly on the left side of the body), weak but not deficient visual-perceptual abilities, deficient visual-spatial skills, extremely poor psychomotor skills (gross motor skills more deficient than fine motor skills), problems with processing of new and complex material, poor visual attention, good auditory memory and relatively good language skills. These findings correspond to the pattern of neuropsychological assets and deficits that has been described for the syndrome of nonverbal learning disabilities (NLD) (Rourke, 1987, 1988, 1989, 1995). The psychosocial profile of all nine children with VCFS also correspond to that of children with NLD. Further studies on the relationship between cognitive function, behavior, psychiatric disorder and abnormalities in brain anatomy in young people with VCFS will be needed. In clinical practice, it is worthwhile exploring in greater depth the neuropsychological functions of children with VCFS to rule out NLD, since they may benefit from specific remediation following the learning principles of the NLD-treatment.
TL;DR: Patients with schizophrenia fail to activate cortical-cerebellar-thalamic-cortical circuitry during recall of both well-learned and novel word lists.
Abstract: OBJECTIVE: This study explored the neural circuitry used during recall of unstructured verbal material in schizophrenic patients and healthy volunteer subjects. METHOD: The subjects were 13 healthy volunteers and 14 schizophrenic patients. All patients were free of medication, and all subjects were right-handed. Two experimental cognitive conditions were used: recall of novel and practiced word lists (two 15-item lists from the Rey Auditory Verbal Learning Test). Both active recall tasks were compared with an eyes-closed resting baseline condition. A nonparametric randomization test was used to determine within- and between-group differences in regional cerebral blood flow. RESULTS: Performance on both the practiced and novel memory tasks was nonsignificantly different in the patients and control subjects. During the novel memory task, the patients showed decreased flow in the right anterior cingulate, right thalamus, and bilateral cerebellum (left greater than right) relative to the control subjects. Whe...
TL;DR: Results are consistent, at least, with the hypothesis that children with autism are challenged by executive tasks because they are unlikely to encode rules in a verbal form.
Abstract: Many studies have shown that children with autism perform at a much lower level than control subjects on tests of executive functioning, defined as tasks requiring subjects to hold information in mind while suppressing a prepotent response. These tasks have invariably required subjects to (a) follow arbitrary and novel rules and (b) make a nonverbal response. We report that when one of these features is absent, children with autism are not impaired relative to controls. They perform at a similar level to normally developing children on the “tubes” task (containing no arbitrary and novel rules) and on the day/night task (in which the output is verbal). Results are consistent, at least, with the hypothesis that children with autism are challenged by executive tasks because they are unlikely to encode rules in a verbal form.
TL;DR: It is confirmed that stimulating central nicotinic receptors has acute cognitive benefit in AD patients and suggested that selective ChCAs have a potential therapeutic role in dementing disorders, and that further studies with this or similar agents in AD and/or Parkinson’s disease are warranted.
Abstract: To explore further the potential for cognitive enhancement utilizing nicotinic stimulation in Alzheimer's disease (AD), six otherwise healthy subjects with moderate AD received placebo and three doses (6, 12, and 23 mg) of the novel selective cholinergic channel activator (ChCA) (nicotinic agonist) ABT-418 over 6 h in a double-blind, within-subjects, repeated-measures design. Subjects showed significant improvements in total recall and a decline in recall failure on a verbal learning task. Qualitatively similar improvements were seen in non-verbal learning tasks such as spatial learning and memory, and repeated acquisition. No significant behavioral, vital sign, or physical side effects were seen. These results confirm that stimulating central nicotinic receptors has acute cognitive benefit in AD patients. These findings suggest that selective ChCAs have a potential therapeutic role in dementing disorders, and that further studies with this or similar agents in AD and/or Parkinson's disease are warranted.
TL;DR: These results suggest disturbed function of temporal lobe, but not basal ganglia, structures in persons with bipolar disorder.
TL;DR: This overview summarizes recent findings applying the framework of the theory of non-linear dynamics to brain electrical activity in the field of epileptology that promise to be important for clinical practice.
TL;DR: The present study supports the idea that estradiol replacement has specific effects on verbal memory in healthy postmenopausal women, with delayed recall being more affected, and suggests that these effects can occur relatively rapidly, and that there may be a dose response relationship of Estradiol to memory enhancement.
TL;DR: Four experiments investigated the role of imagery in the recollection of autobiographical memories and found that visual imageability of cues accounted for more variance in specificity of recall than did predicability.
Abstract: Four experiments investigated the role of imagery in the recollection of autobiographical memories. The first two experiments examined the effects of word imageability and word frequency on the retrieval of personal memories in a cued autobiographical memory task. They showed that the imageability of cues (but not frequency) mediates specificity in the recall of personal memories. Experiment 2 explored how different imagery modalities (visual, olfactory, tactile, auditory, and motor) influence autobiographical retrieval. Consistent with research on imagery modalities in verbal learning paradigms, visual imageability emerged as the most significant predictor of specificity. Experiments 3 and 4 examined how far a knowledge-based account of imagery effects might account for these effects, using predicability as a measure of semantic richness of a cue. Results found that visual imageability of cues accounted for more variance in specificity of recall than did predicability. The results are explained in terms of the way images represent the most efficient form of summarizing the information that can be used at each stage of the recollection process: setting the retrieval plan, strategic search, and evaluation of candidate episodes.
TL;DR: Evidence is presented suggesting that hippocampal NMDA receptors, most likely within the CA1 region, do participate in human verbal memory processes, and that these receptors are involved in human memory.
Abstract: Studies in rodents and nonhuman primates have linked the activity of N-methyl-d-aspartate (NMDA) receptors within the hippocampus to animals’ performance on memory-related tasks. However, whether these receptors are similarly essential for human memory is still an open question. Here we present evidence suggesting that hippocampal NMDA receptors, most likely within the CA1 region, do participate in human verbal memory processes. Words elicit a negative event-related potential (ERP) peaking around 400 ms within the anterior mesial temporal lobe (AMTL-N400). Ketamine, an NMDA-receptor antagonist, reduces the amplitude of the AMTL-N400 (in contrast to other hippocampal potentials) on initial presentation, eliminates the typical AMTL-N400 amplitude reduction with repetition, and leads to significant memory impairment. Of the various hippocampal subfields, only the density of CA1 neurons correlates with the word-related ERPs that are reduced by ketamine. Altogether, our behavioral, anatomical, and electrophysiological results indicate that hippocampal NMDA receptors are involved in human memory.
TL;DR: Children at all ages were more likely to overgeneralize usage of verbs that were less familiar to them, supporting the hypothesis that children's usage of verb in particular construction types becomes entrenched over time.
Abstract: The present study examined English-speaking children's tendency to make argument structure overgeneralization errors (e.g., I disappeared it). Children were exposed to several English verbs of fixed transitivity (exclusively intransitive or exclusively transitive) and then asked questions that encouraged them to overgeneralize usage of the verbs. Seventy-two children (24 in each of three age groups: 3, 4/5, and 8 years of age) experienced four actions performed by puppets. Each action had two verbs of similar meaning associated with it in the context of the experimental action: one more familiar to young children and one less familiar. Children at all ages were more likely to overgeneralize usage of verbs that were less familiar to them, supporting the hypothesis that children's usage of verbs in particular construction types becomes entrenched over time. As children solidly learn the transitivity status of particular verbs, they become more reluctant to use those verbs in other argument structure constructions.
TL;DR: The results further characterize the memory deficits in children with heavy prenatal alcohol exposure suggesting that in spite of learning and memory deficits, they are able to benefit from priming of verbal information.
Abstract: Prenatal alcohol exposure is associated with widespread and devastating neurodevelopmental deficits. Numerous reports have suggested memory deficits in both humans and animals exposed prenatally to alcohol. However, the nature of these memory deficits remains to be characterized. Recently children with fetal alcohol syndrome were shown to have learning and memory deficits on a verbal learning and memory measure that involved free recall and recognition memory. The current study seeks to further characterize memory functioning in children with heavy prenatal alcohol exposure by evaluating priming performance. The choice of task is also relevant given previous studies of memory performance in patient groups with and without involvement of the basal ganglia, a group of structures known to be affected in fetal alcohol syndrome. Three groups were evaluated for lexical priming, free recall, recognition memory, and verbal fluency: (1) children with heavy prenatal alcohol exposure; (2) children with Down syndrome; and (3) nonexposed controls. The children with Down syndrome showed significantly less priming than alcohol-exposed children, who did not differ from controls. In addition, the alcohol-exposed children were impaired on the free recall task but not on the recognition memory task, whereas the children with Down syndrome performed significantly worse than the alcohol-exposed group on both tasks. Finally, on the verbal fluency task, children with heavy prenatal alcohol exposure were impaired on both category and letter fluency, but the degree of impairment was greater for letter fluency. These results further characterize the memory deficits in children with heavy prenatal alcohol exposure suggesting that in spite of learning and memory deficits, they are able to benefit from priming of verbal information.
TL;DR: In this paper, the California Verbal Learning Test (CVLT) was administered to young adult, non-psychotic, depressed inpatients (20 single episode [SE] and 46 recurrent episode [RE]).
Abstract: Although memory deficits are associated with major depressive disorder, few studies have identified which patient characteristics predict impairment. Because recurrent depression appears related to more severe cerebral dysfunction, the present study tested whether recurrent depressed individuals have worse memory function than first-episode depressed individuals. Two groups of young-adult, nonpsychotic, depressed inpatients (20 single episode [SE] and 46 recurrent episode [RE]) were administered the California Verbal Learning Test within a broader battery of neuropsychological tests. The groups were equivalent in age, education, estimated IQ, severity of depression, and demographic composition. The RE group demonstrated memory deficits relative to both the SE group and published norms, but no other significant difference was found across the battery. Data indicate that abnormal memory performance is associated with recurrent depression, whereas memory deficits are not prominent in first-episode depressed individuals.
TL;DR: The intact learning exhibited by PD patients on these tests suggests that nondeclarative cognitive skill learning is not a single entity supported by the neostriatum.
Abstract: Patients with Parkinson's disease (PD) have been shown to be impaired on some nondeclarative memory tasks that require cognitive skill learning (perceptual-motor sequence learning, probabilistic classification). To determine what other skill-based tasks are impaired, 13 patients with PD were tested on artificial grammar learning, artificial grammar learning with transfer to novel lettersets, and prototype learning. Patients with PD performed similarly to controls on all 3 tests. The intact learning exhibited by PD patients on these tests suggests that nondeclarative cognitive skill learning is not a single entity supported by the neostriatum. If learning the regularities among visual stimuli is the principal feature of artificial grammar learning and prototype learning, then these forms of skill learning may be examples of perceptual learning, and they may occur in early visual cortical processing areas.
TL;DR: The results are discussed in terms of current models of reading in which it is proposed that AoA has its primary effect on the retrieval of lexical phonology, which appears to be consulted automatically in the lexical decision task.
Abstract: In five experiments, we examined the respective roles of word age of acquisition (AoA) and frequency in the lexical decision task. The two variables were manipulated orthogonally (while controlling for concreteness and length) in fully factorial designs. Experiment 1 was a conventional lexical decision task, and Experiments 2-5 involved various attempts to interfere with reliance upon phonology. In Experiment 2, only orthographically illegal nonwords were used; in Experiment 3, pseudohomophone nonwords; in Experiment 4, articulatory suppression by the recitation of a nursery rhyme; and in Experiment 5, articulatory suppression by the repetition of a single word. The same basic pattern of results was observed in all experiments: There were main effects of both AoA and frequency, which interacted in such a way that the AoA effect was larger for low- than for high-frequency words. Although the AoA effect was reduced by manipulations intended to interfere with phonological processing, the manipulations did not eliminate the effect. The results are discussed in terms of current models of reading in which it is proposed that AoA has its primary effect on the retrieval of lexical phonology, which appears to be consulted automatically in the lexical decision task.