Richard C. Delaney

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.

Deficits in short-term memory in adult survivors of childhood abuse

Exposure to stress has been associated with alterations in memory function, and we have previously shown deficits in short-term verbal memory in patients with a history of exposure to the stress of combat and the diagnosis of posttraumatic stress disorder (PTSD). Few studies of any kind have focused on adult survivors of childhood physical and sexual abuse. The purpose of this study was to investigate short-term memory function in adult survivors of childhood abuse. Adult survivors of severe childhood physical and sexual abuse (n = 21), as defined by specific criteria derived from the Early Trauma Inventory (ETI), who were presenting for psychiatric treatment were compared with healthy subjects (n = 20) matched for several variables including age, alcohol abuse, and years of education. All subjects were assessed with the Wechsler Memory Scale (WMS) Logical (verbal memory) and Figural (visual memory) components, the Verbal and Visual Selective Reminding Tests (SRT), and the Wechsler Adult Intelligence Scale-Revised (WAIS-R). Adult survivors of childhood abuse had significantly lower scores on the WMS Logical component for immediate and delayed recall in comparison to normal subjects, with no difference in visual memory, as measured by the WMS or the SRT, or IQ, as measured by the WAIS-R. Deficits in verbal memory, as measured by the WMS, were associated with the severity of abuse, as measured by a composite score on the ETI. Our findings suggest that childhood physical and sexual abuse is associated with long-term deficits in verbal short-term memory. These findings of specific deficits in verbal (and not visual) memory, with no change in IQ, are similar to the pattern of deficits that we have previously found in patients with combat-related PTSD.

Defensive coping and blood pressure reactivity in medical patients

Two defensive coping styles, denial of illness and repressive coping, were studied in two groups of medical patients whose blood pressure (BP) was measured during a stress interview. Denial of illness was measured using the Levine Denial of Illness Scale (LDIS), and repressive coping was measured using a combination of the Marlowe-Crowne (MC) Social Desirability Scale and the SCL-90R anxiety subscale (ANX). Consistent with our prior research indicating that LDIS was associated with adaptive outcomes in the short run, high deniers manifested reduced systolic BP reactivity compared to low deniers. Although not related to repressive coping, systolic BP reactivity was correlated positively with MC and ANX separately. The results demonstrate that LDIS and MC measure different types of defensive coping. Current theories of the MC scale suggest two possible interpretations of the MC findings, one that focuses on avoidant coping and the second on attentional coping in high MC scorers.

Complex partial and secondarily generalized seizure patients: cognitive functioning prior to treatment with antiepileptic medication

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.

Transient cerebral ischemic attacks and neuropsychological deficit

Abstract Patients who experienced carotid distribution transient ischemic attacks (TIA) were administered an extensive neuropsychological battery 2–5 days after the clinical clearing of deficits. Significant impairments were noted on measures of higher cortical functioning, including complex memory, abstract concept formation, perceptual-motor integration, and verbal fluency as compared to both published norms and a control group equated for age and years of education. Results are discussed with regard to the heterogeneity of the TIA population, the relationship of the vascular distribution of the TIA to the observed neuropsychological sequelae, weaknesses in published norms with an aging population, and directions for further research.

Neuropsychological Screening for Cognitive Impairment Using Computer-Assisted Tasks:

The aim of this study was to validate a computer-assisted screening battery for classifying patients into two groups, those with and without cognitive impairment. Participants were all patients referred to the neuropsychology clinics at four VA medical centers during a 1-year period. Patients meeting the study inclusionary criteria (N = 252) were administered the Neurobehavioral Evaluation System-3 (NES3) computer-assisted battery. A detailed neuropsychological examination was carried out by an experienced neuropsychologist, who diagnosed the patient as cognitively impaired or not impaired. The neuropsychologists diagnosis was the gold standard. Recursive partitioning analyses yielded several classification procedures using the NES3 data to predict the gold standard. These procedures produced a set of six NES3 tasks that provide good sensitivity and specificity in predicting diagnosis. Sensitivity and specificity for the least random classification procedure were 0.87 and 0.67, respectively. The results suggest that computer-assisted screening methods are a promising means of triaging patients.

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.

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.

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.

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.