Publications by authors named "Mirsky A"

We review the changing conceptions of schizophrenia over the past 50 years as it became understood as a disorder of brain function and structure in which neurocognitive dysfunction was identified at different illness phases. The centrality of neurocognition has been recognized, especially because neurocognitive deficits are strongly related to social and role functioning in the illness, and as a result neurocognitive measures are used routinely in clinical assessment of individuals with schizophrenia. From the original definitions of the syndrome of schizophrenia in the early 20th century, impaired cognition, especially attention, was considered to be important.

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According to Weber's law, a fundamental principle of perception, visual resolution decreases in a linear fashion with an increase in object size. Previous studies have shown, however, that unlike for perception, grasping does not adhere to Weber's law. Yet, this research was limited by the fact that perception and grasping were examined for a restricted range of stimulus sizes bounded by the maximum fingers span.

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Antibodies are glycoproteins produced by the immune system as a dynamically adaptive line of defense against invading pathogens. Very elegant and specific mutational mechanisms allow B lymphocytes to produce a large and diversified repertoire of antibodies, which is modified and enhanced throughout all adulthood. One of these mechanisms is somatic hypermutation, which stochastically mutates nucleotides in the antibody genes, forming new sequences with different properties and, eventually, higher affinity and selectivity to the pathogenic target.

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The emergent processes driving cultural history are a product of complex interactions among large numbers of individuals, determined by difficult-to-quantify historical conditions. To characterize these processes, we have reconstructed aggregate intellectual mobility over two millennia through the birth and death locations of more than 150,000 notable individuals. The tools of network and complexity theory were then used to identify characteristic statistical patterns and determine the cultural and historical relevance of deviations.

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The focus of this review is an analysis of the use of event-related brain potential (ERP) abnormalities as indices of functional pathophysiology in survivors of traumatic brain injury (TBI). TBI may be the most prevalent but least understood neurological disorder in both civilian and military populations. In the military, thousands of new brain injuries occur yearly; this lends considerable urgency to the use of highly sensitive ERP tools to illuminate brain changes and to address remediation issues.

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We report an investigation of P300 measures of information processing in patients with generalized epilepsy of the absence type and those with complex partial epilepsy. Studies have demonstrated that absence patients perform more poorly than complex partial patients on behavioral tests of sustained attention (the Continuous Performance Test, or CPT). Duncan [Duncan, C.

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The concept of mental disorders as diseases of the brain is as old as the ancient Greek philosopher-physicians. However, for thousands of years, the majority of doctors, as well as laypersons, held strongly to the belief that epilepsy and "madness" (i.e.

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Event-related potentials (ERPs) can elucidate aspects of sensory and cognitive processing that have been compromised due to closed head injury. We present the results of two investigations, one previously unreported, in which we used ERPs to evaluate information processing in head-injury survivors. In the first study, we used visual and auditory reaction time tasks differing in attentional demands to assess processing after head trauma.

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Verbal material used to assess the cognitive abilities of Spanish-speakers in the the United States is frequently of linguistically unacceptable quality. The use of these materials in research settings is thought to pose a serious threat to test validity and hence to the validity of claimed results or conclusions. The authors explain how and why incorrect language finds its way into cognitive tests used in research and other settings and suggest solutions to this serious problem.

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We evaluated alterations in information processing after closed head injury as a function of task demands and stimulus modality. Visual and auditory discrimination tasks were administered to 11 survivors of a head injury and 16 matched healthy controls. In auditory tasks, compared with controls, the survivors had smaller N100s, smaller and later N200s, a more posterior scalp distribution of N200, and longer P300 and response latencies.

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To investigate familial effects of neuropsychological deficits associated with seizure disorders, we studied 65 families, in which 1 member had epilepsy. The disorders included childhood absence epilepsy (CAE), juvenile myoclonic epilepsy (JME) and temporal lobe epilepsy (TLE). Age-appropriate tests were administered to assess sustained attention, encoding and verbal memory, executive and focused attention and attentional flexibility/impulsivity.

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The trailblazing research on sleep mechanisms and petit mal epilepsy, conducted during the period from 1940 through 1970, illuminated the brain substrate for normal consciousness and attention, as well as their disorders. This research helped inform and structure our neuropsychologically based model of the "elements" of attention. The model has been used to assess attention in the research laboratory and clinic, and has led to a "nosology of disorders of attention," which is presented here in preliminary form.

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The Genains, a unique group of monozygotic female quadruplets, all developed a schizophrenic disorder by age 24. They have been studied since the 1950s, because of the rarity of this occurrence (estimated to be one in 1.5 billion) and because their illnesses varied in severity.

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Objective: To investigate the relation between neuropsychological dysfunction and volumetric measures of neuroanatomic structures in patients with bipolar disorder.

Background: Previous research suggests that neuropsychological deficits are associated with neuroanatomic changes in patients with bipolar disorder.

Method: Twenty-six outpatients who met Diagnostic and Statistical Manual, Third Edition-Revised criteria for bipolar disorder were administered a battery of neuropsychological tests that assessed memory, abstracting ability, psychomotor performance, sustained attention, and intelligence.

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Background: This study investigated the relationship between prior course of illness and neuropsychological deficits in relatively high functioning outpatients with bipolar disorder.

Method: Forty-nine bipolar I or II patients, in a relatively euthymic state during treatment with mood stabilizers, were administered neuropsychological tests that assessed a variety of functions, including verbal memory, sustained attention and vigilance, and intelligence. A detailed retrospective life chart was completed for each patient using the NIMH Life Chart Method" to define variables reflecting duration and severity of illness, and frequency of episodes.

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Skin conductance (SC) and heart rate (HR) were recorded in two experiments in persons who had suffered a closed head injury (CHI) at least 2 years previously and in control subjects. Experiment 1 consisted of a rest period, a series of innocuous tones, and a short simple reaction time (RT) task. Experiment 2 consisted of initial and final rest periods and a longer RT task with constant and variable preparatory intervals.

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The nature of deficits in attention in closed head injury (CHI) was studied by three reaction time (RT) paradigms given to 20 patients who had a CHI 2 or more years previously and to 25 controls. We studied the effects of temporal uncertainty by varying the length and regularity of the preparatory interval, the effects of stimulus modality uncertainty on simple RT to tones and lights, and the effects of response selection in choice RT. The CHI group showed slower and more variable RT than controls under all conditions.

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Symptoms of DSM-IV attention-deficit hyperactivity disorder (ADHD) were determined in patients entering methadone maintenance treatment. The relationship of ADHD to psychiatric and substance abuse comorbidity, attention testing, and treatment outcome was analyzed; 19% of patients had a history of ADHD, and 88% of these had current symptoms. Continuous Performance Testing indicated poorer attention in patients with ADHD.

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We obtained neuropsychological assessment data on persons from five countries whose ages range from 8 to 90 years. Participants were assessed in four languages. The results from the multivariate analyses indicate that reaction-time measures obtained in tests of sustained attention are minimally affected by country of origin and level of education.

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Twenty-three children with autism and two control groups completed an attention battery comprising three versions of the continuous performance test (CPT), a digit cancellation task, the Wisconsin Card Sorting Test (WCST), and two novel, computerized tests of shifting attention (i.e., the Same-Different Computerized Task and the Computerized Matching Task).

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Previous reports of seasonal variations in P300 were based on cross-sectional observations of subjects tested at different times of the year. In this study, we tested three groups of subjects in each of two seasons: winter and spring, spring and summer, and summer and winter. We found winter or spring maxima in auditory and visual P300 and visual slow wave.

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The goal of this study was to further characterize episodic memory functioning in schizophrenia. This study compared verbal and visual learning and memory performance in (1) patients with schizophrenia (N = 35), (2) patients with temporal lobe epilepsy (TLE; N = 30), and (3) normal controls (N = 25). Results indicated significant memory impairments in patients with schizophrenia and TLE.

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Neurocysticercosis (NCC) is a common neurologic disorder in developing countries, where it may pose a major public health challenge. Recently, the disorder has become more commonly diagnosed in developed countries as a result of the influx of migrants from countries where the disease is endemic. The clinical syndrome associated with NCC includes neurologic, physical, and functional problems.

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