Bruce K. Schefft

Mood and global-local visual processing

Testing hypotheses derived from neuropsychological models of mood, as well as the association of mood states and personality characteristics with global-local visual processing, were examined. Fifty-nine men completed measures associated with depression and positive mood, and were administered a brief perceptual judgment task that assessed global-local visual processing biases. Additionally, 19 of these 59 subjects were administered measures of anxiety and optimism-pessimism and completed an expanded judgment task. Affective and personality variables were then correlated with judgment task performances. Consistent with predictions, positive mood and optimism were directly associated with a global bias and inversely related to a local bias. A converse pattern of findings was obtained with depression and trait anxiety. Implications for research concerning other aspects of visual processing are discussed.

Effects of experimentally-induced emotional states on frontal lobe cognitive task performance

A growing body of evidence suggests that dysphoric and euphoric emotional states are associated with reliable patterns of frontal lobe activity. Specifically, dysphoric affect coincides with greater right than left frontal lobe activity, and euphoric affect tends to correspond with a converse pattern of activity. The present study examined whether cognitive outcomes associated with the left and right frontal lobes are differentially influenced by dysphoric and euphoric affect. In a completely between-groups design, 60 dextral women were administered either the positive or negative conditions of the Velten Mood Induction Procedure, and they subsequently completed either a verbal or figural fluency test. Euphoria resulted in better verbal than figural fluency performance, and dysphoria yielded better figural than verbal fluency outcomes. These findings are consistent with electrophysiological data concerning frontal lobe activity during euphoric and dysphoric affect, and they underscore the notion that affective influences upon cognition are more complicated than previously thought.

Mood, Personality, and Health‐related Quality of Life in Epileptic and Psychogenic Seizure Disorders

Summary:  Purpose: Patients with psychogenic nonepileptic seizures (PNES) rate their health‐related quality of life (HRQOL) more poorly than those with epileptic seizures (ES). This has been explained in part by mood state. We sought to investigate whether HRQOL differences between diagnostic groups (PNES vs. ES) can be explained by additional, perhaps chronic, aspects of mood and personality. An understanding of these relationships may inform treatment designed to improve HRQOL in ES or PNES.

Recovery in pediatric brain injury: is psychostimulant medication beneficial?

Objective:To assess the effects of methylphenidate on attention, memory, behavior, processing speed, and psychomotor skills of children with closed head injuries. Design:Double-blind, placebo-controlled, crossover design. Setting:An outpatient facility of a childrens hospital medical center. Patients:Ten pediatric subjects identified through chart review. Subjects met baseline scores for hyperactivity (Conners Hyperactivity Index 560) and intellectual functioning (Verbal Intelligence Quotient £70) and achieved minimal scores on two psychometric tests. All subjects evidenced head injury by focal lesions on computed tomography scan and/or sequelae reported at the time of injury. Severity of injury ranged from mild to severe. All subjects were medically stable at the time of testing. Mean time post injury was 2 years, 8 months. Intervention:Administration of methylphenidate and placebo. Main Outcome Measures:Percentage change in scores was calculated to assess differences between baseline and end of methylphenidate/ placebo trials. Results:No significant differences between methylphenidate and placebo on measures assessing behavior, attention, memory, and processing speed. Conclusions:The results of the study call into question the effectiveness of methylphenidate in the pediatric head injury population.

Medial temporal fMRI activation reflects memory lateralization and memory performance in patients with epilepsy

Memory difficulties are a frequent cognitive complaint of patients with chronic epilepsy. Previous studies have suggested that the presence of a seizure focus causes reorganization of brain mechanisms underlying memory function. Here we examine whether seizure onset in the left hemisphere and onset in the right hemisphere have different effects on memory lateralization and whether longer duration of epilepsy is associated with increased lateralization of memory functions to the unaffected hemisphere. We hypothesized that hemisphere of onset and duration of epilepsy would influence plasticity of memory mechanisms, similar to the plasticity observed for language mechanisms. Healthy controls (HC, N = 10) and patients with epilepsy (N = 23, 11 with a left- and 12 with a right-hemisphere focus) performed a scene-encoding fMRI task at 4 T. Active voxels (relative to scrambled image viewing) were identified for each participant. Memory laterality indices (LIs) were calculated in three regions of interest (ROIs) designed on the basis of HC group data: a functional ROI, an anatomical-hippocampal ROI, and an anatomical-medial temporal ROI encompassing hippocampus and parahippocampal gyrus. In healthy controls, LIs were suggestive of slight left lateralization of encoding memory for pictures. Patients with right hemisphere epilepsy showed a nonsignificant increase in degree of left lateralization. In contrast, patients with left hemispheric epilepsy showed right-lateralized activation, differing significantly from controls and from patients with right hemispheric epilepsy. Neuropsychological measures of memory (WMS-III Story Recall) across epilepsy patients predicted LIs in the anatomical ROIs: higher scores were associated with more left-lateralized medial temporal fMRI activation. Neither age of onset nor duration of epilepsy was significantly related to LI. These results indicate that focal epilepsy may influence the functional neuroanatomy of memory function.

The effect of seizures on working memory and executive functioning performance

The aim of this study was to assess whether duration of seizure disorder and lifetime seizure load are associated with deficits in higher cognitive functions in patients with temporal lobe epilepsy (TLE) (N=207) or psychogenic nonepileptic seizures (PNES) (N=216). Multivariate regression analyses revealed that age at onset, duration, and group assignment were significant predictors of neuropsychological performance (all P<or=0.02), with group having a moderating relationship. Univariate analyses revealed different patterns of predictor effects on cognitive functioning within each diagnostic group. An impairment index was calculated for each individual, and univariate analyses revealed that age at TLE but not PNES onset was the only significant predictor of impairment (b=-0.005, P<0.001). The results suggest that earlier age at seizure onset, longer duration, and higher lifetime seizure frequency affect cognitive functioning in both the TLE and PNES groups, but differently within each group. These results have implications for early diagnosis and intervention in both groups.

Accuracy of Self-Reported Neuropsychological Functioning in Individuals with Epileptic or Psychogenic Nonepileptic Seizures

The aim of this study was to determine the degree to which subjective ratings of neurocognitive ability accurately reflect objectively measured neuropsychological functioning in patients diagnosed with epileptic (ES, n = 45) or psychogenic nonepileptic (PNES; n = 37) seizures. Patients received a battery of neuropsychological tests, measures of current mood state, and the Quality of Life In Epilepsy-89 questionnaire. Results indicated that subjective ratings of neuropsychological functioning were only partially accurate within each group. Patients with ES accurately rated their memory function, but overestimated language and attention abilities. Patients with PNES accurately rated attention, but underestimated memory and overestimated language. In both groups, poorer self-reported neurocognitive functioning was strongly related to poorer mood state; however, mood state did not predict objectively measured neurocognitive abilities. Given the inaccuracies that exist in patient self-report, results highlight the importance of a comprehensive neuropsychological assessment when evaluating the neurocognitive status of individuals with seizures.

Preoperative assessment of confrontation naming ability and interictal paraphasia production in unilateral temporal lobe epilepsy

The present study examined the diagnostic utility of confrontation naming tasks and phonemic paraphasia production in lateralizing the epileptogenic region in patients with temporal lobe epilepsy (TLE). Further, the role of intelligence in moderating the diagnostic utility of confrontation naming tasks was assessed. Eighty patients with medically intractable complex partial seizures (40 left TLE, 40 right TLE) received the Boston Naming Test (BNT) and the Visual Naming subtest (VNT) of the Multilingual Aphasia Examination. The BNT was diagnostically more sensitive than the VNT in identifying left TLE (77.5% vs 17.5%, respectively). The utility of BNT performance and paraphasias was maximal in patients with Full Scale IQs >or=90 who were 6.8 times more likely to have left TLE than patients without paraphasias. Preoperative assessment of confrontation naming ability and phonemic paraphasia production using the BNT provided diagnostically useful information in lateralizing the epileptogenic region in left TLE.

Preserved color imagery in an achromatopsic.

The loss of color vision secondary to central nervous system disease (achromatopsia) is thought to preclude visual imagery of colors. We report a patient with achromatopsia, secondary to bilateral temporo-occipital infarcts inclusive of the lingual and fusiform gyri, with preserved color imagery. Our findings, in conjunction with previous cases in the literature, are consistent with a single neural network for color processing in which a disconnection of internal activation from stored color representations produces impaired color imagery with preserved color perception, whereas a disconnection of visual input to these representations produces achromatopsia with preserved color imagery.

Repetition and the arcuate fasciculus.

According to the traditional model of language organization, repetition deficits arise following damage to the arcuate fasciculus of the dominant hemisphere (conduction aphasia). Conduction aphasia may result from lesions that spare the arcuate fasciculus. However, these patients have atypical language organization. We describe a man with normal language architecture who underwent a resection of the anterior portion of his arcuate fasciculus and retained his ability to repeat words and sentences. We propose that the arcuate fasciculus is not necessary for speech repetition by the lexical route.