Biomedical subjects

J DeLuca

Publications and source records attributed to J DeLuca.

At least 19 recordsLinked to original sources

PubMed2004

Prevalence of stimulant use for attentional dysfunction in children with phenylketonuria.

Recent data suggest that children with phenylketonuria (PKU) and poor metabolic control may have an increased prevalence of attentional dysfunction. However, few formal studies have addressed this topic in detail. We reviewed the medical records of 38 school-aged children with early and continuously treated PKU to determine the prevalence of stimulant use for attentional dysfunction, and to determine the relationship between metabolic control and attentional symptoms. Twenty-six per cent of the PKU children used a stimulant medication for attentional dysfunction. This is significantly higher than in an age- and sex-matched control group consisting of children with type I diabetes mellitus (6.5%, p <0.006), and also considerably higher than population norms for attention deficit hyperactivity disorder (ADHD) (5%). We also found a significant relationship between phenylalanine levels and stimulant use or attentional symptoms. Mean plasma phenylalanine concentration was 486 micromol/L in the non-stimulant-using group and 792 micromol/L in the stimulant-using group (p <0.02). Mean phenylalanine concentration was 462 micromol/L in the group not reporting attentional symptoms, and was 702 micromol/L in the symptomatic group (p <0.05). Parents of the stimulant-using children felt that the stimulants were efficacious in treating their child's attentional symptoms. Stimulant use and parent reports of attentional dysfunction are quite common in our PKU patients and appear to be strongly related to higher phenylalanine concentrations.

Adolescent↗

PubMed2003

Spacing of repetitions improves learning and memory after moderate and severe TBI.

Extensive research has determined that new learning in healthy individuals is significantly improved when trials are distributed over time (spaced presentation) compared to consecutive learning trials (massed presentation). This phenomenon known as the "spacing effect" (SE) has been shown to enhance verbal and nonverbal learning in healthy adults of different ages and in different memory paradigms (e.g., recognition, recall, etc.). The purpose of this study was to examine whether learning in adults with moderate and severe traumatic brain injury (TBI) is improved using a spacing-of-repetitions procedure. Using a within-groups design, participants with TBI (n = 20) were presented a list of 115 words that were presented either once (single condition), twice consecutively (massed condition), or twice with 11 words between presentations (spaced condition). Participants were required to rank each word from 1 to 10 according to their familiarity with the word; they were not asked to "memorize" words for a later test. Word list learning was measured with a free recall test immediately following list presentation and with free recall and recognition tests after a 30-min delay. Participants recalled and recognized significantly more spaced words than massed words during this word list learning task. These results strongly indicate that the spacing of repetitions improves learning and memory in individuals who have sustained moderate to severe TBI. Implications for rehabilitation are discussed.

Adolescent↗

PubMed2003

An investigation of working memory rehearsal in multiple sclerosis using fMRI.

The present study examined patterns of cerebral activation during a working memory (WM) rehearsal task in individuals diagnosed with multiple sclerosis (MS) and in healthy adults. BOLD functional magnetic resonance imaging (fMRI) was performed using a 1.5 T GE scanner to assess activation during a WM task adapted from the Sternberg paradigm (Sternberg, 1969). Participants included 8 individuals diagnosed with MS, and 5 healthy controls (HCs) matched for age and education. Task difficulty was manipulated by increasing the length of time that strings of letters were to be rehearsed. Findings revealed increased right prefrontal cortex activation and increased right temporal lobe activation in individuals diagnosed with MS compared to HCs. The potential explanations for increased right hemisphere activation in persons with MS are discussed.

Adolescent↗

PubMed2001

The influence of cognitive impairment on driving performance in multiple sclerosis.

OBJECTIVE: To examine the influence of impaired cognitive processing on measures of driving skills in persons with MS. METHODS: Twenty-eight subjects with documented MS were divided into two groups-with [MS(+), n = 13] and without [MS(-), n = 15] cognitive impairment-based on neuropsychological performance. Healthy control (HC) subjects (n = 17) matched on age and driving experience were also studied. Driving-related skills were compared between the groups based on performance on two computerized driving tests: the Useful Field of Vision (UFOV) and the Neurocognitive Driving Test (NDT). RESULTS: The MS(+) group performed significantly worse than both the MS(-) and HC groups in the latency to perform several driving-specific functions on the NDT, but no overall group differences were observed in actual errors on the NDT. On the UFOV, when compared to MS(-) and HC subjects, the MS(+) group demonstrated poorer performance on two of the three subtests. Additionally, a significantly higher percentage of MS(+) individuals were rated within the high risk (probability of crash involvement) category, relative to the MS(-) and HC groups. CONCLUSIONS: Cognitive impairment can negatively affect driving-related skills in persons with MS and should be considered in the determination of driving ability.

Adult↗

PubMed2001

Functionally activated brain imaging (O-15 PET and fMRI) in the study of learning and memory after traumatic brain injury.

Advances in functional imaging technology and cognitive neuropsychology have resulted in paradigms in which participants can perform cognitive tasks during functional image acquisition. We will discuss the application of two approaches (oxygen-15 positron emission tomography and functional magnetic resonance imaging) that have recently been used to examine components of learning and memory following traumatic brain injury (TBI). Activated functional brain imaging findings that we will discuss may suggest possible functional reallocation and reorganization of brain substrates involved in verbal learning and memory following brain injury. The findings also are clearly in line with other research that indicates a prominent role for the frontal lobes in learning and memory functioning, and support the concept of distributed neural networks for memory-related functions, cognitive load, and the potential for examining brain re-organization after injury.

Brain Injuries↗

PubMed2001

Functional magnetic resonance imaging of working memory impairment after traumatic brain injury.

OBJECTIVES: To examine patterns of brain activation while performing a working memory task in persons with moderate to severe traumatic brain injury (TBI) and healthy controls. It is well established that working memory is an area of cognition that is especially vulnerable to disruption after TBI. Although much has been learned about the system of cerebral representation of working memory in healthy people, little is known about how this system is disrupted by TBI. METHODS: Functional magnetic resonance imaging (fMRI) was used to assess brain activation during a working memory task (a modified version of the paced auditory serial addition test) in nine patients with TBI and seven healthy controls. RESULTS: Patients with TBI were able to perform the task, but made significantly more errors than healthy controls. Cerebral activation in both groups was found in similar regions of the frontal, parietal, and temporal lobes, and resembled patterns of activation found in previous neuroimaging studies of working memory in healthy persons. However, compared with the healthy controls, the TBI group displayed a pattern of cerebral activation that was more regionally dispersed and more lateralised to the right hemisphere. Differences in lateralisation were particularly evident in the frontal lobes. CONCLUSIONS: Impairment of working memory in TBI seems to be associated with alterations in functional cerebral activity.

Adult↗

PubMed2001

Quantitative assessment of cerebral ventricular volumes in chronic fatigue syndrome.

Previous qualitative volumetric assessment of lateral ventricular enlargement in chronic fatigue syndrome (CFS) has provided evidence for subtle structural changes in the brains of some individuals with CFS. The aim of this pilot study was to determine whether a more sensitive quantitative assessment of the lateral ventricular system would support the previous qualitative findings. In this study, we compared the total lateral ventricular volume, as well as the right and left hemisphere subcomponents in 28 participants with CFS and 15 controls. Ventricular volumes in the CFS group were larger than in control groups, a difference that approached statistical significance. Group differences in ventricular asymmetry were not observed. The results of this study provide further evidence of subtle pathophysiological changes in the brains of participants with CFS.

Adult↗

PubMed2001

Longitudinal assessment of neuropsychological functioning, psychiatric status, functional disability and employment status in chronic fatigue syndrome.

The longitudinal course of subjective and objective neuropsychological functioning, psychological functioning, disability level, and employment status in chronic fatigue syndrome (CFS) was examined. The relations among several key outcomes at follow-up, as well as the baseline characteristics that predict change (e.g., improvement), were also evaluated. The study sample consisted of 35 individuals who met the 1988 and 1994 CFS case definition criteria of the Centers for Disease Control (CDC) at intake. Participants were evaluated a mean of 41.9 (SEM = 1.7) months following their initial visit (range = 24-63 months). Results indicated that objective and subjective attention abilities, mood, level of fatigue, and disability improve over time in individuals with CFS. Moreover, improvements in these areas were found to be interrelated at follow-up. Finally, psychiatric status, age, and between-test duration were significant predictors of outcome. Overall, the prognosis for CFS appears to be poor, as the majority of participants remained functionally impaired over time and were unemployed at follow-up, despite the noted improvements.

Adult↗

PubMed2001

Relationship of brain MRI abnormalities and physical functional status in chronic fatigue syndrome.

Chronic Fatigue Syndrome (CFS) is an unexplained illness that is characterized by severe fatigue. Some have suggested that CFS is a "functional somatic syndrome" in which symptoms of fatigue are inappropriately attributed to a serious illness. However, brain magnetic resonance imaging (MRI) data suggest that there may be an organic abnormality associated with CFS. To understand further the significance of brain MRI abnormalities, we examined the relationship between MRI identified brain abnormalities and self-reported physical functional status in 48 subjects with CFS who underwent brain MR imaging and completed the Medical Outcomes Study SF-36. Brain MR images were examined for the presence of abnormalities based on 5 general categories previously shown to be sensitive to differentiating CFS patients from healthy controls. There were significant negative relationships between the presence of brain abnormalities and both the physical functioning (PF) (rho=-.31, p=.03), and physical component summary PCS (rho=-.32, p=.03) subscales of the SF-36. CFS patients with MRI identified brain abnormalities scored significantly lower on both PF (t(1,46) =2.3, p=.026) and the PCS (t(1,41) =2.4, p=.02) than CFS subjects without an identified brain abnormality. When adjusted for age differences only the PF analysis remained significant. However, the effect sizes for both analyses were large indicating meaningful differences in perceived functional status between the groups. These results demonstrate that the presence of brain abnormalities in CFS are significantly related to subjective reports of physical function and that CFS subjects with MRI brain abnormalities report being more physically impaired than those patients without brain abnormalities.

Adult↗

PubMed2001

A comparison of memory performance in relapsing-remitting, primary progressive and secondary progressive, multiple sclerosis.

OBJECTIVE: The current investigation was designed to examine the influence of disease course on the specific patterns of acquisition and retrieval impairments in multiple sclerosis (MS). BACKGROUND: Recent investigations of learning and memory in MS have shown that many subjects have impaired verbal and visual new learning abilities, but normal long-term recall and recognition. However, heterogeneity in the learning and memory abilities of subjects has been documented. Some evidence in the literature suggests that this heterogeneity may be in part attributable to clinical variables, such as disease course. METHODS: Verbal and visual learning and memory tests, modified to equate MS groups with healthy controls on initial acquisition of information, were administered to 64 individuals with clinically definite MS (relapse-remitting = 21; primary progressive = 18; secondary progressive = 25), and to 20 healthy control participants. Recall and recognition performance then was evaluated at 30 minutes, at 90 minutes, and at 1 week for the verbal learning task, and at 30 minutes and at 90 minutes for the visual learning task. RESULTS: Results indicate that the two progressive forms of MS result in significantly greater deficits in regard to the acquisition of new verbal information, with the secondary progressive group showing a significantly higher failure rate in regard to meeting the learning criterion. Performance for recognition measures was not significantly different among groups, whereas recall performance of the primary progressive group was significantly below that of the control group and of the secondary progressive group. When testing new learning with visuospatial information, individuals with relapse-remitting MS and secondary progressive MS required more trials than control participants to learn the same amount of visual information. Visual recall and recognition performance did not differ between groups. No group differences in rates of forgetting for visuospatial material was observed after equating for acquisition. CONCLUSIONS: Results of the current study indicate that the primary problem in MS with regard to memory functioning is in the acquisition of new information. Our findings support previous research showing verbal memory deficits with a progressive disease course and visuospatial memory deficits in relapse-remitting MS. However, the detailed analysis of new learning and memory performed in the current study indicated that the primary progressive group may be showing difficulty in their ability to use newly learned information. The pattern of new learning deficits observed between MS disease subtypes in the current study was determined to be unrelated to the duration of MS and to the physical severity of the disease. The degree of physical disability observed in patients with MS does not appear to be related to the degree of cognitive decline because of the distinct patterns and severity of memory dysfunction noted within each disease type, independent of physical disability.

Adult↗

PubMed2001

Impaired delay eyeblink classical conditioning in individuals with anterograde amnesia resulting from anterior communicating artery aneurysm rupture.

Anterior communicating artery (ACoA) aneurysm rupture can lead to an anterograde amnesia syndrome similar to that observed after damage to the hippocampus and medial temporal lobes (MT). It is currently believed that ACoA amnesia results from basal forebrain damage that disrupts hippocampal processing without direct hippocampal damage. Converging evidence from animal studies and computational modeling suggests that qualitative differences may exist in the pattern of memory impairment after basal forebrain or MT damage. For example, animals with basal forebrain but not hippocampal damage are impaired at delay eyeblink classical conditioning (EBCC). In this study, individuals with ACoA amnesia were shown to be impaired at delay EBCC compared with matched controls; this contrasts with the spared delay EBCC previously observed in MT amnesia. This finding suggests the beginning of a possible dissociation between the memory impairments in MT versus ACoA amnesia.

Adult↗

PubMed2000

Organizational strategy influence on visual memory performance after stroke: cortical/subcortical and left/right hemisphere contrasts.

OBJECTIVE: To examine how organizational strategy at encoding influences visual memory performance in stroke patients. DESIGN: Case control study. SETTING: Postacute rehabilitation hospital. PARTICIPANTS: Stroke patients with right hemisphere damage (n = 20) versus left hemisphere damage (n = 15), and stroke patients with cortical damage (n = 11) versus subcortical damage (n = 19). MAIN OUTCOME MEASURES: Organizational strategy scores, recall performance on the Rey-Osterrieth Complex Figure (ROCF). RESULTS: Results demonstrated significantly greater organizational impairment and less accurate copy performance (i.e., encoding of visuospatial information on the ROCF) in the right compared to the left hemisphere group, and in the cortical relative to the subcortical group. Organizational strategy and copy accuracy scores were significantly related to each other. The absolute amount of immediate and delayed recall was significantly associated with poor organizational strategy scores. However, relative to the amount of visual information originally encoded, memory performances did not differ between groups. CONCLUSIONS: These findings suggest that visual memory impairments after stroke may be caused by a lack of organizational strategy affecting information encoding, rather than an impairment in memory storage or retrieval.

Adult↗

PubMed2000

Stressors, personality traits, and coping of Gulf War veterans with chronic fatigue.

OBJECTIVES: preliminary surveys of Persian Gulf veterans revealed a significant prevalence of self-reported symptoms consistent with chronic fatigue syndrome (CFS). The purpose of this study was to compare self-reported life stressors, combat, and chemical exposures, personality and coping between Gulf War veterans with CFS and healthy veterans. METHODS: following a complete physical, psychiatric, and neuropsychological evaluation, 45 healthy veterans, 35 veterans with CFS and co-morbid psychiatric disorder, and 23 veterans with CFS and no co-morbid psychiatric disorder completed questionnaires assessing war and non-war-related life stressors, self-reports of environmental exposure (e.g. oil well fires, pesticides), personality, and coping. RESULTS: measures of personality, self-reported combat and chemical exposures, and negative coping strategies significantly differentiated healthy veterans from those with CFS. CONCLUSION: a biopsychosocial model of veterans' illness was supported by the fact that personality, negative coping strategies, life stress after the war, and environmental exposures during the war were significant predictors of veterans' current physical function.

Adaptation, Psychological↗

PubMed2000

Acquisition versus retrieval deficits in traumatic brain injury: implications for memory rehabilitation.

OBJECTIVE: To examine whether impaired memory in persons with traumatic brain injury (TBI) is caused by impaired initial acquisition or compromised retrieval from long-term storage. DESIGN: Prospective matched controlled trial. SETTING: Postacute rehabilitation institute. PARTICIPANTS: Patients with moderate to severe TBI (n = 28) and 21 matched, healthy controls (HCs). MAIN OUTCOME MEASURES: Patients with TBI and HC subjects were equated on initial acquisition on a verbal list-learning task. Recall and recognition performance was then evaluated at 30- and 90-minutes after learning. RESULTS: All HC subjects and 20 subjects with TBI (TBI-MET) were able to meet the learning criterion, but the TBI-MET group took significantly more trials than HC subjects to do so. However, after equating groups on acquisition, the TBI-MET group did not differ from controls on recall and recognition at both the 30- and 90-minute delays. Eight TBI subjects showed severe learning deficits (TBI-NOT MET) because they never learned the task, and showed significantly impaired recall and recognition performance. The 2 TBI groups did not differ on measures of severity of injury, but the TBI-NOT MET group performed significantly below the TBI-MET group on executive functioning. Rate of forgetting did not differ across the 3 groups. CONCLUSIONS: Results suggest that memory impairment after TBI is caused primarily by deficiencies in initial acquisition of verbal information rather than in compromised retrieval. The findings have significant implications for the rehabilitation and treatment of individuals with TBI.

Adolescent↗

PubMed2000

Learning impairment is associated with recall ability in multiple sclerosis.

Recent evidence suggests that persons with multiple sclerosis may experience deficits in verbal and visuospatial acquisition rather than recall. The present study was designed to determine whether this finding generalized to a broader range of neuropsychological tests of learning and memory. To control for group differences in information acquisition, healthy controls (HCs) and persons with multiple sclerosis (MS) were trained to specific learning criteria on both verbal (i.e., paragraph learning and paired associates) and visuospatial (i.e., facial recognition) memory tasks. Persons with MS required significantly more learning trials to meet criteria on the paragraph learning and facial recognition tasks, but not the paired associates test. However, after learning comparable amounts of information, the MS and HC groups recalled statistically similar amounts of information at 30-minutes, 90-minutes, and up to 1-week on the paragraph learning and paired associate tests. This suggests that persons with MS may have deficits in acquisition rather than recall per se. Results are discussed in terms of possible rehabilitation strategies to improve memory functioning in persons with MS.

Adult↗

PubMed2000

Speed of information processing in traumatic brain injury: modality-specific factors.

OBJECTIVE: To assess speed of information processing by two serial addition tests (one visual, one auditory) in individuals with moderate-to-severe traumatic brain injuries (TBIs) and in a healthy, normal control group (NC). The tasks were designed to equate and control for accuracy of performance across the TBI and NC groups, thus allowing for quantification of information processing speed. DESIGN: Performance across groups and tasks were compared using 2 x 2 repeated measure analyses of variance (ANOVAs). In addition, each individual's processing speed was used to adjust rate of stimulus presentation on a subsequent "rehabilitation" trial to determine further whether this adjustment equated accuracy of performance. SETTING: Rehabilitation hospital. PATIENTS: 22 outpatients with moderate-to-severe TBI (6 women, 16 men; mean age = 34.6 years; duration of loss of consciousness = 22.6 days) and 20 age- and education-matched healthy controls. RESULTS: Processing speed was slower in TBI subjects, relative to controls and was significantly related to measures of executive functioning for those with TBI. Relative to controls, speed of processing in the TBI group was disproportionately slower when information was presented in the auditory, relative to the visual, modality. CONCLUSIONS: Speed of information processing is a major impairment in those with TBI when unconfounded by performance accuracy. The modality-specific impairment observed in the TBI group may, in part, be due to a greater within-modality interference effect created by the auditory version of the task. By manipulating information at a pace customized for an individual through compensatory strategies and environmental modifications, information-processing performance of TBI participants can be enhanced significantly.

Adult↗

PubMed1999

Psychiatric diagnoses in Gulf War veterans with fatiguing illness.

The purpose of this study was to determine whether Gulf War Illness (GWI) can be explained by the presence of psychiatric disorders as assessed by DSM-III-R. To reduce the heterogeneity amongst Persian Gulf War veterans with GWI (PGV-F), only those were studied who presented with severe fatigue as a major complaint and also fulfilled clinical case definitions for Chronic Fatigue Syndrome, Idiopathic Chronic Fatigue, and/or Multiple Chemical Sensitivity. A total of 95 Registry PGVs were examined; 53 presented with GWI and 42 did not report any post-war health problems (PGV-H). All subjects were assessed for the presence of DSM-III-R Axis I psychiatric disorders. Compared to PGV-Hs, 49% of PGV-Fs had similar post-war psychiatric profiles: either no, or only one, psychiatric disorder was diagnosed. Psychiatric profiles of the remaining 51% of PGV-Fs were significantly different from PGV-Hs in that most of these veterans suffered from multiple post-war psychiatric diagnoses. The presence of psychiatric disorders as assessed by DSM-III-R criteria cannot explain symptoms of Gulf War Illness among all Persian Gulf veterans with severe fatiguing illness.

Adult↗

PubMed1999

Brain MRI abnormalities exist in a subset of patients with chronic fatigue syndrome.

Presence of MRI brain abnormalities in patients with Chronic Fatigue Syndrome (CFS) was determined and the profile of MRI abnormalities was compared between 39 CFS patients, 18 with (CFS-Psych) and 21 without (CFS-No Psych) a DSM-III-R Axis I psychiatric diagnosis since illness onset, and 19 healthy, sedentary controls (HC). Two neuroradiologists, blind to group membership, separately read the MR films using a detailed protocol for rating and categorizing abnormal signal changes. When findings were incongruent, the two neuroradiologists met to try to reach consensus, otherwise a third neuroradiologist evaluated the MR images and served as a tie-breaker. The CFS-No Psych group showed a significantly larger number of brain abnormalities on T2 weighted images than the CFS-Psych and HC groups. Cerebral changes in the CFS-No Psych group consisted mostly of small, punctate, subcortical white matter hyperintensities, found predominantly in the frontal lobes. No significant difference was found when both CFS groups were combined and compared to the HC group. The use of stratification techniques is an important strategy in understanding the pathophysiology of CFS. This frontal lobe pathology could explain the more severe cognitive impairment previously reported in this subset of CFS patients.

Adult↗