Biomedical subjects

J Vincent Filoteo

Publications and source records attributed to J Vincent Filoteo.

At least 19 recordsLinked to original sources

PubMed2007

Within-category discontinuity interacts with verbal rule complexity in perceptual category learning.

A test of the predicted interaction between within-category discontinuity and verbal rule complexity on information-integration and rule-based category learning was conducted. Within-category discontinuity adversely affected information-integration category learning but not rule-based category learning. Model-based analyses suggested that some information-integration participants improved performance by recruiting more "units" in the discontinuous condition. Verbal rule complexity adversely affected rule-based category learning but not information-integration category learning. Model-based analyses suggested that the rule based effect was on both decision criterion learning and variability in decision criterion placement. These results suggest that within-category discontinuity and decision rule complexity differentially impact information-integration and rule-based category learning and provide information regarding the detailed processing characteristics of these two proposed category learning systems.

Concept Formation↗

PubMed2007

Neuropsychology of cortical versus subcortical dementia syndromes.

Neuropsychological studies have shown that there are several prominent differences in the patterns of cognitive deficits that occur in neurodegenerative disorders that have their primary etiology in either cortical or subcortical brain dysfunction. Quantitative and qualitative differences are apparent across many cognitive domains, including memory (in all its aspects), attention, executive functions, language and semantic knowledge, and visuospatial abilities. These distinct patterns of deficits have been broadly characterized as forming cortical and subcortical dementia syndromes. Differentiating between cortical and subcortical dementia provides a heuristically useful model for understanding brain-behavior relationships in neurodegenerative diseases and may improve the ability to clinically distinguish among various dementing disorders.

Alzheimer Disease↗

PubMed2006

Flanker compatibility effects in patients with Parkinson's disease: impact of target onset delay and trial-by-trial stimulus variation.

Parkinson's disease (PD) patients and healthy controls were administered a flanker task that consisted of the presentation of colored targets and distractors. Participants were required to attend to the center target and identify its color. The stimulus displays were either congruent (i.e., the target and flankers were the same color) or incongruent. The time between the onset of the flanker and the target color (the target onset delay) was either short or long. Results indicated that PD patients and controls did not differ in the magnitude of the flanker effect within individual trials in that both groups demonstrated a typical flanker effect at the short target onset delay and neither group demonstrated a flanker effect at the longer delay. However, when performance was examined on a trial-by-trial basis, PD patients demonstrated a slowing of reaction time relative to controls when having to make the same response across consecutive trials at longer inter-trial intervals when the flankers were incongruent across consecutive trials and the display on the second of two trials was incongruent. These results indicate that PD patients are impaired in inhibiting the distractors over an extended delay and that this deficit may impact motor responding in these patients, suggesting that the basal ganglia contribute to the interface of attention and action.

Aged↗

PubMed2006

Characterizing rule-based category learning deficits in patients with Parkinson's disease.

Parkinson's disease (PD) patients and normal controls were tested in three category learning experiments to determine if previously observed rule-based category learning impairments in PD patients were due to deficits in selective attention or working memory. In Experiment 1, optimal categorization required participants to base their decision on a single stimulus dimension and ignore irrelevant variation on another dimension, thus emphasizing selective attention processes. In Experiment 2, optimal categorization required participants to base their decision on both stimulus dimensions using a conjunction of unidimensional decisions. Thus, this task placed less emphasis on selective attention and more on working memory. In Experiment 3, optimal categorization again required participants to base their decision on both stimulus dimensions using a disjunction of two unidimensional decisions in which an additional verbal operation was needed, thereby placing even greater emphasis on working memory. Results indicated that PD patients were impaired in the unidimensional rule-based condition, but not the other two rule-based conditions. These results are consistent with previous studies that demonstrate that PD patients are impaired in learning rule-based categories when selective attention demands are greatest, whereas these patients are normal in learning rule-based tasks when working memory demands are emphasized. Overall, these findings help to delineate the conditions under which PD patients display rule-based category learning deficits.

Aged↗

PubMed2006

Quantitative measurement of handwriting in the assessment of drug-induced parkinsonism.

Monitoring drug-induced side effects is especially important for patients who undergo treatment with antipsychotic medications, as these drugs often produce extrapyramidal side effects (EPS) resulting in movement abnormalities similar to parkinsonism. Scientists have developed several objective laboratory tests to measure and research drug-induced movement disorders, but equipment and tests are complex and costly and have not become accepted in large-scale, multi-site clinical trials. The goals of this study were to test whether a simple handwriting measure can discriminate between individuals with psychotropic-induced parkinsonism, Parkinson's disease, and healthy individuals, and to examine some of the psychometric properties of the measure. We examined pen movement kinematics during cursive writing of a standard word in 13 patients with idiopathic Parkinson's disease (PD), 10 schizophrenia patients with drug-induced parkinsonism (SZ), and 12 normal healthy control participants (NC). Participants were instructed to write the word "hello" in cursive twice, at three vertical height scales. Software was used for data acquisition and analysis of vertical stroke velocities, velocity scaling, and smoothness. There were four important results from this study: (1) both SZ patients with drug-induced EPS and PD participants exhibited impaired movement velocities and velocity scaling; (2) performance on the velocity scaling measure distinguished drug-induced EPS from normal with 90% accuracy; (3) SZ, but not PD participants displayed abnormalities in movement smoothness; and (4) there was a positive correlation between age and magnitude of the velocity scaling deficit in PD participants. This study demonstrates that kinematic analyses of pen movements during handwriting may be useful in detecting and monitoring subtle changes in motor control related to the adverse effects of psychotropic medications.

Adult↗

PubMed2006

Episodic memory in patients with focal frontal lobe lesions.

Episodic memory was evaluated in patients with unilateral, frontal lobe damage and matched controls using a list-method directed forgetting paradigm. Directed forgetting instructions (forget vs. remember the word), encoding instructions (learn vs. judge the word) and test format (recall vs. recognition) were manipulated in order to explore how variations in encoding and retrieval affect verbal memory. Controls demonstrated a normal directed forgetting effect in recall and less directed forgetting in recognition. Patients with left frontal (LF) damage did not show directed forgetting in either recall or recognition and patients with right frontal (RF) damage showed directed forgetting in recall, but not in recognition. Furthermore, the LF group recalled significantly more of the judge than learn words, suggesting that this group's performance improves by providing them with an encoding strategy. Conversely, the RF group's performance did not depend on encoding instructions and their recognition memory was impaired relative to the other two groups when they were instructed to judge the words. Our results suggest that (a) patients with LF damage show deficits in the rehearsal of to-be-remembered information, (b) whereas patients with RF damage show impairments in recognition memory. Furthermore, both patient groups show a lack of directed forgetting when familiarity-based processes guide performance.

Adult↗

PubMed2006

Lack of impairment in patients with Parkinson's disease on an object-based negative priming task.

12 nondemented patients with Parkinson's disease (M age = 67.3) and 12 normal control participants were administered an object-based attention task that enabled examination of both negative and positive priming. Unlike previous studies in which spatial-based attention tasks were used, results of the present study indicated that the patients displayed negative and positive priming not different from those shown by controls. These results suggest that certain object-based attentional processes may not be impaired in patients with Parkinson's disease.

Aged↗

PubMed2005

Cortical and subcortical brain regions involved in rule-based category learning.

The brain regions contributing to rule-based category learning were examined using fMRI. Participants categorized single lines that varied in length and orientation into one of two categories. Category membership was based on the length of the line. Results indicated that left frontal and parietal regions were differentially activated in those participants who learned the task as compared to those who did not. Further, the head of the caudate displayed relative decreases in activation on incorrect trials relative to correct trials. The involvement of this latter structure is likely related to (1) processing an error signal, or (2) volitional switching between potential category rules. Results are consistent with theories suggesting that a frontal-striatal circuit is involved in rule-based category learning.

Adult↗

PubMed2005

Semantic priming in patients with right frontal lobe lesions.

Patients with unilateral, right frontal lobe damage (N=13) and matched controls (N=20) performed a task of lexical ambiguity resolution in order to explore the contribution of right frontal regions to lexical-semantic priming. Word triplets consisting of balanced homographs were presented to participants in four conditions: concordant, discordant, neutral, and unrelated. Controls demonstrated facilitation for concordant meanings of homographs, as evidenced by their faster reaction times in the concordant relative to the unrelated (baseline) condition, as well as a lack of facilitation for the discordant meaning relative to the neutral and concordant conditions. Results in patients with right frontal lobe damage differed depending on the site of the lesion. Patients with lesions restricted to the right medial frontal lobe only showed facilitation in the neutral condition, while those with lesions encroaching upon the right dorsolateral region demonstrated facilitation of both discordant and concordant meanings relative to the baseline condition. These results support a role for the right frontal lobe in semantic priming and suggest possible specialization within the right prefrontal cortex for the processing of lexical-semantic information.

Adult↗

PubMed2005

The impact of irrelevant dimensional variation on rule-based category learning in patients with Parkinson's disease.

This study examined the impact of irrelevant dimensional variation on rule-based category learning in patients with Parkinson's disease (PD), older controls (OC), and younger controls (YC). Participants were presented with 4-dimensional, binary-valued stimuli and were asked to categorize each into 1 of 2 categories. Category membership was based on the value of a single dimension. Four experimental conditions were administered in which there were zero, 1, 2, or 3 randomly varying irrelevant dimensions. Results indicated that patients with PD were impacted to a greater extent than both the OC and YC participants when the number of randomly varying irrelevant dimensions increased. These results suggest that the degree of working memory and selective attention requirements of a categorization task will impact whether PD patients are impaired in rule-based category learning, and help to clarify recent discrepancies in the literature.

Aged↗

PubMed2005

Discontinuous categories affect information-integration but not rule-based category learning.

Three experiments were conducted that provide a direct examination of within-category discontinuity manipulations on the implicit, procedural-based learning and the explicit, hypothesis-testing systems proposed in F. G. Ashby, L. A. Alfonso-Reese, A. U. Turken, and E. M. Waldron's (1998) competition between verbal and implicit systems model. Discontinuous categories adversely affected information-integration but not rule-based category learning. Increasing the magnitude of the discontinuity did not lead to a significant decline in performance. The distance to the bound provides a reasonable description of the generalization profile associated with the hypothesis-testing system, whereas the distance to the bound plus the distance to the trained response region provides a reasonable description of the generalization profile associated with the procedural-based learning system. These results suggest that within-category discontinuity differentially impacts information-integration but not rule-based category learning and provides information regarding the detailed processing characteristics of each category learning system.

Adult↗

PubMed2005

Information-integration category learning in patients with striatal dysfunction.

Information-integration category learning was examined in patients with Parkinson's disease (PD) and in healthy control participants in 2 different conditions. In the linear condition, optimal categorization required a nonverbalizable linear integration of information from the 2 stimulus dimensions, whereas in the nonlinear condition, a nonlinear integration of information was required. Each participant completed 600 trials in each condition and was given corrective feedback following each trial. Results indicated that PD patients were not impaired in the linear condition across all trials, whereas the same patients were impaired in the nonlinear condition, but only later in training. The authors conducted model-based analyses to identify participants who used an information-integration approach, and a comparison of the accuracy rates of those individuals further revealed a specific deficit in information-integration category learning in patients with PD. These findings suggest that the striatum may be particularly involved in information-integration category learning when the rule is highly complex.

Aged↗

PubMed2005

Attentional inhibition in patients with focal frontal lobe lesions.

Patients with unilateral, frontal lobe damage and matched controls performed an identity negative priming task as a measure of inhibition in selective attention. Control participants demonstrated a normal negative priming effect, as evidenced by slower reaction times when a previously to-be-ignored item became the target on a subsequent trial (distractor suppression). On the other hand, patients with left medial frontal lobe damage showed positive priming in the distractor suppression condition suggesting facilitation of distractor information. Patients with right frontal lobe damage showed an unreliable pattern of negative priming, some demonstrating an absence of negative priming and others demonstrating enhanced negative priming in the distractor suppression condition. Neither patient group nor controls demonstrated slower responses on a target-to-distractor condition included to evaluate a noninhibitory (i.e., episodic retrieval) account of negative priming. Taken together, our results suggest that (a) the negative priming effect represents active inhibition of a distractor representation, rather than a noninhibitory mismatch between retrieval episodes, and (b) that the frontal lobes, especially the left frontal lobes, contribute to this active inhibition.

Adult↗

PubMed2005

Is a perseveration a perseveration? An evaluation of cognitive error types in patients with subcortical pathology.

This study investigated several constructs of executive functioning in a group of 77 patients with subcortical pathology. Specifically, we examined the validity of categorizing perseverative errors as "recurrent," "stuck-in-set," or "continuous," as proposed by Sandson and Albert (1984). A principal components analysis of 2 measures of recurrent perseveration, 2 measures of stuck-in-set perseveration, and 2 measures of intrusive errors yielded a 2 component solution with stuck-in-set perseverations and intrusive errors loading on Component 1, and recurrent perseverations loading on Component 2. Presence of a continuous perseveration on a graphomotor test was significantly associated with higher factor scores on Component 1, but not Component 2. The stuck-in-set perseveration and intrusion component was associated with the majority of the other neuropsychological tests administered, including tests of executive function and memory. The recurrent perseveration component was not associated with the other measures of cognitive functioning. Presence of a continuous perseveration was associated with executive function but not memory measures. This study provides evidence that recurrent perseverations are distinct from the other types of perseverative and intrusive errors, and that stuck-in-set and intrusive errors are good indicators of general cognitive functioning in patients with subcortical pathology.

Adult↗

PubMed2005

The ubiquity of memory retrieval deficits in patients with frontal-striatal dysfunction.

OBJECTIVE AND BACKGROUND: Previous studies have shown that patients with frontal-striatal dysfunction demonstrate improved performance on tests of recognition memory relative to free recall memory, suggesting deficits in retrieval processes. Not all studies, however, have indicated that all patients with frontal-striatal dysfunction display this profile. In this study, we examined the ubiquity of this "retrieval deficit" profile in a relatively large sample of patients with Parkinson disease (PD) or Huntington disease (HD). METHODS: Participants included 150 patients with PD and 65 patients with HD. Patients were classified as demonstrating a retrieval deficit or not based on a comparison of their standardized performances on the Recognition Discriminability and Long-Delay Free Recall indices from the California Verbal Learning Test. RESULTS: Results indicated that 1) a retrieval deficit was more prevalent in patients with HD than PD, 2) this group difference emerged only in patients with at least a mild level of global cognitive impairment, and 3) even when the profile did emerge more frequently in patients with HD, it was present in only 44% of the patients. CONCLUSIONS: These findings suggest that not all patient groups with frontal-striatal dysfunction display a retrieval deficit profile, but in groups that do (ie, patients with HD), it is more likely to appear in individuals with greater cognitive impairment.

Aged↗

PubMed2004

Category number impacts rule-based but not information-integration category learning: further evidence for dissociable category-learning systems.

Category number effects on rule-based and information-integration category learning were investigated. Category number affected accuracy and the distribution of best-fitting models in the rule-based task but had no effect on accuracy and little effect on the distribution of best-fining models in the information-integration task. In the 2 category conditions, rule-based learning was better than information-integration learning, whereas in the 4 category conditions, unidimensional and conjunctive rule-based learning was worse than information-integration learning. Rule-based strategies were used in the 2-category/rule-based condition, but about half of the observers used rule-based strategies in the 4-category unidimensional and conjunctive rule-based conditions. Information-integration strategies were used in the 4-category/ information-integration condition and by the end of training were used in the 2-category/information-integration condition.

Adult↗

PubMed2004

A quantitative model-based approach to examining aging effects on information-integration category learning.

Information-integration category learning was examined in older and younger adults. Accuracy results indicated that older participants learned less well than younger participants in both linear and nonlinear conditions. Model-based analyses indicated that both groups in the linear condition tended to use information integration but that later in training younger participants were more likely to do so. In contrast, the 2 groups in the nonlinear condition were equally likely to use information integration. Further analysis indicated that younger adults were more accurate than older adults when an information-integration approach was adopted, whereas fewer age-related differences were observed when a rule-based approach was used, suggesting that age can have a negative impact on information-integration category learning processes but less impact on rule-based learning.

Adult↗

PubMed2003

Recognition memory for hand positions and spatial locations in patients with Huntington's disease: differential visuospatial memory impairment?

Allocentric and egocentric memory was investigated in patients with Huntington's disease (HD) and matched controls. Patients with HD and age- and education-matched healthy normal controls (NC) were administered two visuospatial recognition memory tasks, one assessing memory for hand positions (egocentric) and the other assessing memory for spatial locations (allocentric). HD patients showed normal primacy and recency effects, but their overall performance was impaired relative to controls on both tasks. Correlation analyses indicated that HD patients' performance on the Hand Position Memory task, but not the Spatial Location Memory task, was associated with global cognitive status (Mattis Dementia Rating Scale) and disease severity (Shoulson and Fahn Rating Scale), and HD patients' performances on the two tasks were not associated. Results provide preliminary support for the role of the caudate nucleus in both allocentric and egocentric spatial memory.

Adolescent↗