Biomedical subjects

R C Delaney

Publications and source records attributed to R C Delaney.

16 recordsLinked to original sources

PubMed1998

Complex partial and secondarily generalized seizure patients: cognitive functioning prior to treatment with antiepileptic medication. VA Epilepsy Cooperative Study 264 Group.

This investigation of cognitive functioning in patients with symptomatic localization-related (partial) epilepsy prior to administration of antiepileptic medication is part of a nationwide prospective, double-blind study of drug efficacy and longitudinal changes in cognition associated with seizure disorders. Recently-diagnosed patients with complex partial or secondarily generalized tonic clonic seizures, equated for age, education and IQ, were compared with normal controls on a battery of neuropsychological tests: verbal and figural memory measures (Rey auditory verbal learning test, Rey Osterrieth complex figure), and a brief behavioral toxicity battery comprising measures of motor function, concentration and mental flexibility (Lafayette grooved pegboard, controlled word association test, Stroop, paced auditory serial addition test [PASAT]). Control subjects perform significantly better than both groups of seizure patients on several measures of motor speed/integration and memory, specifically the pegboard and the RAVLT learning (3-5) and recall trials. Secondarily generalized seizure patients show greatest impairment. They perform significantly worse than patients with complex partial seizures and control subjects on the controlled word association test and the most demanding Stroop color word trial, both measures of concentration and mental flexibility. These findings document deficits in memory as well as concentration and motor function in complex partial and in secondarily generalized seizure patients prior to treatment with antiepileptic medication.

Adult↗

PubMed1996

Effect of valproate on cognitive functioning. Comparison with carbamazepine. The Department of Veterans Affairs Epilepsy Cooperative Study 264 Group.

OBJECTIVE: To assess the effects of carbamazepine vs valproate sodium on cognitive functioning in patients with epilepsy compared with normal control subjects. DESIGN: Patients with recently diagnosed, previously unmedicated seizures participated in a prospective randomized double-blind Department of Veterans Affairs multicenter study of the efficacy and toxicity of carbamazepine vs valproate. MAIN OUTCOME MEASURE: A behavioral toxicity battery was administered prior to treatment and again 6 and 12 months after the initiation of antiepileptic medication. RESULTS: There were no significant differences in the effect of carbamazepine vs valproate on motor speed and coordination, memory, or concentration and mental flexibility, and there was no significant decline in neuropsychological performance from pretreatment baseline levels for either drug. No significant differences in performance were found between patients with low (mean, 52.8 micrograms/mL) vs high (mean, 94.4 micrograms/mL) serum valproate levels within the therapeutic range. Patients treated with either carbamazepine or valproate did not show practice effects experienced by normal controls, a finding that may reflect a subtle compromise in cognitive functioning. CONCLUSION: The impact of carbamazepine and valproate monotherapy on cognitive functioning is similar: both drugs produce minimal negative effects compared with pretreatment baseline performance.

Adult↗

PubMed1996

Comparison of technetium-99m-HMPAO and technetium-99m-ECD cerebral SPECT images in Alzheimer's disease.

UNLABELLED: SPECT has shown increasing promise as a diagnostic tool in Alzheimer's disease (AD). Recently, a new SPECT brain perfusion agent, 99mTc-ethyl cysteinate dimer (99mTc-ECD) has emerged with purported advantages in image quality over the established tracer, 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO). This research aimed to compare cerebral images for 99mTc-HMPAO and 99mTc-ECD in discriminating patients with AD from control subjects. METHODS: Twenty-four AD patients (mean age +/- s.d. = 68.9 +/- 8.2 yr) and 13 healthy subjects (68.4 +/- 8.0 yr) were scanned sequentially with 20 mCi of each tracer using the CERASPECT system within 1 mo. Scanning began on average 11.5 +/- 2.8 min after 99mTc-HMPAO injection and 41.8 +/- 10.1 min after 99mTc-ECD. A ratio, R, was derived of count densities in "typically affected" brain structures (parietal and temporal association cortices) to "unaffected" structures (cerebellum, basal ganglia, thalamus, occipital cortex, and sensorimotor cortex). RESULTS: Analysis of variance revealed significant interaction between diagnostic group and radiopharmaceutical (F = 4.71; df = 1.35; p = 0.04), with 99mTc-ECD demonstrating better separation of R values between AD patients and control subjects than 99mTc-HMPAO. Receiver operating characteristic (ROC) analysis, revealed no significant difference in the ability of the two tracers to correctly classify AD patients and control subjects. Both tracers showed high diagnostic accuracy (99mTc-ECD: sensitivity = 100%, specificity = 92%; 99mTc-HMPAO: sensitivity = 100%, specificity = 85%). CONCLUSION: Technetium-99m-ECD shows greater contrast than 99mTc-HMPAO between affected and unaffected brain structures in AD when patients are compared to age-matched control subjects. Both tracers perform equally well in correctly classifying patients and control subjects.

Aged↗

PubMed1995

Right hemisphere mediation of verbal learning and memory in acquired right hemisphere speech dominant patients.

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.

Adult↗

PubMed1995

MRI-based measurement of hippocampal volume in patients with combat-related posttraumatic stress disorder.

OBJECTIVE: Studies in nonhuman primates suggest that high levels of cortisol associated with stress have neurotoxic effects on the hippocampus, a brain structure involved in memory. The authors previously showed that patients with combat-related posttraumatic stress disorder (PTSD) had deficits in short-term memory. The purpose of this study was to compare the hippocampal volume of patients with PTSD to that of subjects without psychiatric disorder. METHOD: Magnetic resonance imaging was used to measure the volume of the hippocampus in 26 Vietnam combat veterans with PTSD and 22 comparison subjects selected to be similar to the patients in age, sex, race, years of education, socioeconomic status, body size, and years of alcohol abuse. RESULTS: The PTSD patients had a statistically significant 8% smaller right hippocampal volume relative to that of the comparison subjects, but there was no difference in the volume of other brain regions (caudate and temporal lobe). Deficits in short-term verbal memory as measured with the Wechsler Memory Scale were associated with smaller right hippocampal volume in the PTSD patients only. CONCLUSIONS: These findings are consistent with a smaller right hippocampal volume in PTSD that is associated with functional deficits in verbal memory.

Adult↗

PubMed1993

Deficits in short-term memory in posttraumatic stress disorder.

OBJECTIVE: The purpose of this study was to compare the memory function of patients with posttraumatic stress disorder (PTSD) to that of matched comparison subjects. METHOD: Vietnam veterans with combat-related PTSD (N = 26) were compared to physically healthy comparison subjects (N = 15) matched for age, race, sex, years of education, handedness, socioeconomic status, and alcohol abuse. Memory and intelligence were assessed with a battery of neuropsychological tests, including the Russell revision of the Wechsler Memory Scale, the Selective Reminding Test, and subtests of the Wechsler Adult Intelligence Scale-Revised (WAIS-R). RESULTS: The PTSD patients scored significantly lower than the comparison subjects on the Wechsler Memory Scale logical memory measures for immediate recall (mean = 11.6, SD = 3.3 versus mean = 20.9, SD = 6.6) and delayed recall (mean = 8.0, SD = 3.3 versus mean = 17.8, SD = 6.4). The PTSD patients also scored significantly lower on the total recall, long-term storage, long-term retrieval, and delayed recall measures for the verbal component of the Selective Reminding Test and on the recall, long-term storage, long-term retrieval, and continuous long-term retrieval measures for the visual component of the Selective Reminding Test. There was no significant difference between the PTSD patients and comparison subjects in prorated full-scale IQ as measured by the WAIS-R. CONCLUSIONS: Patients with PTSD may have deficits in short-term memory. Counseling and rehabilitation that address these deficits may be of value for PTSD patients.

Humans↗

PubMed1992

Test-retest comparability and control subject data for the Rey-Auditory Verbal Learning Test and Rey-Osterrieth/Taylor Complex Figures.

This report presents data from a nonpatient sample considering the test-retest reliability and task comparability of the Rey-Osterrieth/Taylor Complex Figures and the Rey Auditory Verbal Learning Test. These tasks were presented to normal comparison subjects as a component of a large Department of Veterans Affairs Cooperative Study on anticonvulsant effects in a manner typical of routine clinical use. The results suggest a high degree of reliability for the Rey-Auditory Verbal Learning Test, supporting its use for test-retest situations. However, cautions are discussed for the use of the Rey-Osterrieth-Taylor Complex Figure comparisons.

Journal Article↗

PubMed1991

Feeling-of-knowing in temporal lobe epilepsy: monitoring knowledge inaccessible to conscious recall.

Feeling-of-Knowing was compared in left temporal, right temporal, and control subjects. Seizure patients, like controls, demonstrate knowledge of information that is not accessible to conscious recall, but they are less accurate in FOK judgements. Furthermore, there are significant differences between seizure patients and controls in the relationship between Feeling-of-Knowing and object level memory scores: (1) Controls spend more time searching memory for inaccessible information that is correctly identified on a later recognition test than they do for information that is incorrectly recognized. (2) Latency of correct recognition decreases as strength of FOK increases among controls, suggesting that controls correctly anticipate the outcome of memory search. These patterns of performance, which are consistent with an efficient memory search termination device, were not observed among seizure patients. The findings suggest that inaccurate Feeling-of-Knowing may play a role in inefficient memory search mechanisms in temporal lobe epilepsy.

Adult↗

PubMed1991

A method of assessing the efficacy of memory rehabilitation techniques using a "real-world" memory task: learning a computer language.

A software program developed to assess the effectiveness of memory rehabilitation techniques is described. This project addresses current weaknesses in the research literature on memory rehabilitation: 1) remediation strategies are evaluated in terms of performance on a practical, real-world memory task, rather than a laboratory learning task; 2) the program allows maximum flexibility in assessing a wide variety of remediation strategies and training schedules; and, 3) the software, which provides sensitive outcome measures and detailed feedback about performance, is adaptable to the needs of patients with widely varying degrees of memory impairment. The results of a demonstration project are included to illustrate the use of this technology in determining the usefulness of different mnemonic strategies for patients with specific patterns of memory deficit. The importance of assessing maintenance of rehabilitation training over time is stressed.

Computer Graphics↗

PubMed1989

Transcranial magnetic stimulation: an assessment of cognitive and other cerebral effects.

To assess possible persistent cerebral effects, we acquired EEG, measured serum prolactin, and administered cognitive and motor tests before and after transcranial magnetic stimulation of 30 healthy adults. We found no detrimental effects on EEG or test performance. A slight but statistically significant decline in serum prolactin lacked correlation with the extent of stimulation.

Adult↗

PubMed1988

Metamemory in temporal lobe epilepsy: self-monitoring of memory functions.

Temporal lobe seizure patients and control subjects participated in an investigation of metamemory. The two-part study explored the individual's perception of memory abilities for both encoding and retrieval. Experiment I addressed self-monitoring of encoding through a study of prediction of memory span. Experiment II explored self-monitoring of retrieval through a study of "Feeling of Knowing." The results indicate that left and right temporal lobe seizure patients tend to overestimate their memory capacities, in comparison with normal controls, and that self-monitoring tends to be less accurate for material (verbal or nonverbal) mediated by side of lesion. The potential impact of inaccurate memory monitoring on the memory dysfunction observed in seizure patients is discussed.

Adult↗

PubMed1988

Gist recall in temporal lobe seizure patients (a study of adaptive memory skills).

This study investigates the capacity of lateralized temporal lobe seizure patients to process and retain complex narrative information, to recall the most important elements of verbal material, and to make effective use of mnemonic strategies during a brief study period to improve performance. Compared to normal controls, both left and right temporal lobe samples recall significantly less information on both immediate and post-study trials. In addition seizure patients, particularly left temporal subjects, engaged in fewer active learning strategies and produced more instances of major distortion. However, despite their reduced efficiency in total recall, seizure patients, like control subjects, do tend to remember a higher proportion of important idea units and a smaller proportion of details. The findings are discussed in relation to previous research which documented memory monitoring failures in temporal lobe seizure patients, and in terms of the development of adaptive memory skills to circumvent memory deficits.

Adaptation, Psychological↗

PubMed1986

Short term retention with lateralized temporal lobe epilepsy.

This investigation focused upon whether individuals with lateralized temporal-lobe epilepsy have impairments in short term memory and, if so, whether these impairments are of a material-specific nature. The Peterson short term memory distractor paradigm which consists of single, brief presentations of stimuli with varying decay intervals and appropriate interpolated distractors was employed. A significant deficit in both left and right temporal lobe seizure groups was documented in comparison to controls for verbal but not for non-verbal materials. The results suggest that one aspect of the memory problem observed in temporal lobe seizure patients relates to relatively early components of information processing where encoding is primarily based upon physical rather than semantic characteristics of the stimulus and material-specificity is less evident.

Adolescent↗

PubMed1986

Neuropsychological signs of asymptomatic carotid stenosis.

Several investigators have reported cognitive deficits associated with symptomatic carotid artery disease. This paper reports the findings of a study investigating cognitive deficits associated with asymptomatic carotid stenosis. Experimental subjects consisted of six patients who, in the course of routine physical examinations, showed carotid bruits and, on carotid ultrasound studies, showed 70% or greater stenosis in one or both arteries. No clinical symptoms had been associated with that stenosis. Six control subjects who were group-matched in terms of age and years of education were drawn from a control group evaluated previously for comparison with a transient ischemic attack (TIA) sample. All patients received a battery of tests consisting of a Wechsler Adult Intelligence Scale-Revised, abbreviated Halstead-Reitan Neuropsychological Battery, Revised Wechsler Memory Scale, and a written word fluency measure. Findings were converted to Rating Equivalents according to standard guidelines and an average Impairment Index was computed for each subject. ANOVA revealed that the two groups were significantly different in terms of the average Impairment Index. The clinical significance of these findings is discussed and implications for future research are reviewed.

Journal Article↗

PubMed1982

Screening for organicity: the problem of subtle neuropsychological deficit and diagnosis.

Considered the clinical efficacy of a promising test used to screen for organic brain dysfunction in adults by applying that measure to several types of epileptic patient samples (N = 60) in comparison to control Ss (N = 15). Results indicate that the Canter Background Interference Procedure for the Bender-Gestalt Test cannot differentiate such neurological groups from controls and that its hit rate in such diagnostic situations is disappointingly low. The issue of assessing subtle yet significant disorders is discussed with recommendations to consider the nature of the referral question and aspects of the patient's history in deciding upon appropriate test applications and to maintain a flexible approach in neuropsychological differential evaluations.

Adolescent↗

PubMed1980

Memory function in focal epilepsy: a comparison of non-surgical, unilateral temporal lobe and frontal lobe samples.

Three well-matched groups of non-surgical, pharmacologically controlled epileptic patients with unilateral seizure foci in either the left temporal lobe, the right temporal lobe or a frontal lobe, and a normal control group were compared on several verbal and non-verbal memory tasks. Results revealed significant impairment of verbal memory in left temporal epileptic subjects, and significant impairment of non-verbal, visual memory in right temporal epileptic subjects. Seizure patients with unilateral frontal lobe foci did not differ from the control sample on any measure. Results support previous research which emphasizes the importance of temporal lobe systems in memory function. The findings are discussed with regard to the nature and specificity of the observed deficits.

Adolescent↗