A nosology of disorders of attention.

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. The nosology reviews the possible causes of the symptom(s) of impaired attention, as well as suggesting a blueprint for future research in this area.

A 39-year followup of the Genain quadruplets.

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. The identical inheritance would tend to rule out genetic differences as the cause of the neuropsychological differences; however, we cannot disentangle the effects of early brain injury and harsh punitive treatment as factors accounting for the differences in the severity of their disorders. We conducted neuropsychological examinations of the Genains at age 66, compared their test profiles, and contrasted certain test scores at 66 with those at ages 27 and 51. Test results indicate generally stable (or even improved) performance over time and support the notion that cognitive decline is not a degenerative process in schizophrenia. The Genains remind us of the exquisite interaction among variables that must be understood before additional, satisfactory progress can be made in preventing the development and predicting the course of schizophrenia.

A preliminary study of the relation of neuropsychological performance to neuroanatomic structures in bipolar disorder.

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. Patients also received a magnetic resonance imaging scan, from which volumes of the temporal lobes, hippocampus, third ventricle, and areas of the lateral ventricles were calculated. Using multiple regression analyses, neuroanatomic structures were compared with neuropsychological test variables. RESULTS: Data suggest that a larger right hippocampal volume is associated with poorer neuropsychological functioning. CONCLUSIONS: Further studies are needed to both replicate and examine the relation between potential mechanisms of neuroanatomic alterations and neuropsychological dysfunction in patients with bipolar disorder.

Autonomic activity during task performance in adults with closed head injury.

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. The results from both protocols showed no group differences in HR, SC levels, or SC fluctuations during rest periods, but the SC variables increased less to the task instructions in the CHI group. There were no differences in SC response frequency or magnitude to innocuous tones, but the CHI subjects had fewer SC responses to the RT stimuli in both experiments. SC responses to both innocuous tones and RT stimuli had longer latencies in the CHI group. The results show that selective deficits in tonic and phasic autonomic responding to meaningful, significant, or demanding situations and stimuli are long-term sequelae to CHI. These attenuated activation increases may be related to inadequate mobilization of processing resources and to behavioral deficits shown by these patients.

Reaction time indicators of attention deficits in closed head injury.

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. In addition, a long preparatory interval on the preceding trial retarded RT more in the CHI group, and they showed greater effects of stimulus modality uncertainty. Both of these findings suggest a difficulty in shifting attention to unexpected stimuli. These greater effects on RT of variations of attention or preparation in CHI may account for their greater within-subject variability possibly due to frontal lobe damage.

Attention deficit hyperactivity disorder and treatment outcome in opioid abusers entering treatment.

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. The only substance use disorder more common in the ADHD group was clonidine. There was significantly more current axis I, dysthymic disorder, anxiety disorder (including social phobia), and antisocial personality disorder in the ADHD patients. There was no difference between groups at the 1-year follow-up for illicit drug use, treatment retention, or treatment performance. The ADHD diagnosis did not convey significant prognostic implications for methadone maintenance treatment. A strong psychiatric assessment and treatment focus in the treatment program may help to explain the good treatment outcome.

Relationship between prior course of illness and neuropsychological functioning in patients with bipolar disorder.

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. RESULTS: Stepwise multiple regression analyses show that several different measures of a more severe course of prior illness related to greater duration and a larger number of affective episodes and hospitalizations were associated with poorer performance on tests of abstraction, attention and memory. CONCLUSION: The results indicate that bipolar patients with a more severe prior course of illness and a greater number of affective episodes have more impaired neuropsychological functioning. The direction of causality and the pathophysiological mechanisms remain to be explored.

Sex differences in seasonal variations in P300.

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. This pattern of results, with the amplitude of P300 being inversely related to the amount of sunlight in a season, supports the hypothesis that the allocation of processing resources varies across the seasons. Our results also suggest a trend for an increased sensitivity of women, as compared with men, to seasonal influences on P300. Although our findings do not provide strong evidence that P300 varies systematically as a function of season, seasonal factors appear to affect cognitive processing (as indexed by P300) differentially in men and women.

Comparative effects of schizophrenia and temporal lobe epilepsy on memory.

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. "Savings" score measures of memory decay showed that the loss of information in schizophrenia and TLE was approximately equal, and quantitatively mild compared to that found in most neurologic groups with memory disorders. The severe difficulty shown by the schizophrenia group on a task of incidental recall suggested that the absence of instructional set added to a vulnerability to memory deficit. In contrast, relatively mildly impaired performance on paired associate learning suggested that patients with schizophrenia benefited from retrieval cues, multiple trials, and short (nonsupraspan) informational loads. Because patients with schizophrenia consisted of a relatively nonchronic sample with a mean IQ of 99.7, their memory disorder could not be attributed to schizophrenic dementia, nor was it accounted for by other potential confounds. Patients with schizophrenia, even those relatively early in the course of illness, have a mild episodic memory disorder.

Attentional capacities in children with autism: is there a general deficit in shifting focus?

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). Children with autism could focus on a particular stimulus and sustain this focus as indicated by their performance on the digit cancellation task and the CPT. Their performance on the WCST suggested problems in some aspects of shifting attention (i.e., disengaging attention). The autism group performed as well as controls on the Same-Different Computerized Task, however, that required successive comparisons between stimuli. This implies that they could, in fact, shift their attention continuously. In addition, they did not differ from controls on the Computerized Matching Task, an analog of the WCST, suggesting that they do not have a general deficit in shifting attention.

Multinational neuropsychological testing: performance of children and adults.

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. In contrast, tests assessing the ability to focus attention and solve a problem, to shift strategies, and to inhibit an automatic response tendency differ significantly by country and level of education. Most of these differences tend to disappear at about the age of 54. The data provide partial support for the hypothesis of commonality of some neuropsychological functions across cultures.

Neurocysticercosis and performance on neuropsychologic tests: a family study in Ecuador.

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. Since the locus of the infection is mainly the central nervous system, there is a risk of neuropsychologic dysfunction. This study was conducted in Ecuador in a group of 123 subjects (49 males and 74 females, 9-62 years of age) from a community sample that was part of a larger neuroepidemiologic inquiry. A discriminant function procedure was used to select the tests that would be most sensitive at distinguishing between affected and nonaffected individuals. The results suggest that behavioral functions that include aspects of inhibitory control, motor, and visual-motor output are impaired in adolescent and adult subjects with NCC.

Perils and pitfalls on the path to normal potential: the role of impaired attention. Homage to Herbert G. Birch.

The research of Herbert Birch and colleagues, conducted 30 years ago in a rural area of Guatemala, called attention to the permanent noxious effects on cognitive development associated with conditions of poverty. Half of the world's population, including millions of persons in the United States, are still afflicted by these conditions. Included among these are malnutrition, disease, toxic agents, perinatal injury, and lack of intellectual/social stimulation. Recent research findings on the cognitive effects of these poverty-related variables are presented; the effects appear to be expressed in a reduction of the brain's capacity to engage in attentive behavior. Neuropsychologists, by virtue of their interests and training, are in a position to develop methods of assessing and correcting these deficits, and must become advocates of improved conditions to foster better brain development for all of the world's children.

EEG abnormalities, malnutrition, parasitism and goitre: a study of schoolchildren in Ecuador.

We report on data collected in a sample of 194 schoolchildren (9-13 years of age) residing in a mountainous community in Ecuador. This study was part of an ongoing epidemiological inquiry into the prevalence of parasitism, malnutrition, neurocysticercosis, goitre, iodine levels and EEG abnormalities, and the relationships among these factors. Data were obtained by a local medical team supported by specialized personnel. The results showed that 34% of the EEG tracings were abnormal, with higher rates among girls. The best fitted log-linear model to explain the results was the combination of EEG status, parasite infection, goitre and gender. The best predictor of EEG abnormalities was found to be a diagnosis of goitre.

Analysis of the attention deficit in schizophrenia: a study of patients and their relatives in Ireland.

County Roscommon, a rural area in the western part of Ireland, was the site of a family study of schizophrenia. As part of this study, we have assessed several elements of attention, identified by principal components analysis in previous investigations, in a group of subjects with schizophrenia, first-degree relatives of subjects with schizophrenia and age- and education-matched controls. The schizophrenic subjects performed significantly more poorly than the controls; the performance of the relatives fell somewhere between the other two groups. Those relatives with a DSM-III-R diagnosis (most frequently, alcohol abuse or an affective disorder) tended to perform more poorly on some of the attention elements than relatives without a diagnosis; in contrast, control subjects with diagnoses were not distinguishable from other controls. The attention elements appeared to differ in their capacity to differentiate the groups and each seemed to have a distinctive profile. The effects of alcohol abuse were also considered. The results obtained with this cohort may provide clues concerning the pathophysiological basis of schizophrenia and the heterogeneity of its expression.

Israeli High Risk Study: editor's introduction.

The National Institute of Mental Health joint study by the United States and Israel, known as the Israeli High-Risk Study,is a unique long-term followup investigation of children at genetic risk for schizophrenia. We compared the development of psychiatric disorder in two groups of such children, one group raised in kibbutz environments, the other by their own parents. Matched controls were studied as well. The subjects were evaluated at ages 11, 17, and 26; an extensive battery of cognitive and clinical tests, as well as psychophysiological and diagnostic procedures, was used. This issue of the Schizophrenia Bulletin reports and summarizes evaluations conducted when the subjects were in their early thirties, as well as some previously unreported data obtained when the subjects were 17 years old.

Neuropsychological assessment of attention and its pathology in the Israeli cohort.

We assessed attention in 63 of the 98 traceable living subjects of the original 100 in the National Institute of Mental Health (NIMH) joint study of schizophrenia by the United states and Israel, known as the Israeli High-Risk Study cohort; their mean age was 32 years. These data were supplemented, for comparative purposes, with those obtained on 31 normal control and 17 schizophrenia subjects studied at NIMH. The results suggest that attention skills of the adult children of a parent with schizophrenia fall between those of schizophrenia patients and controls, and that measures of sustained attention and the ability to focus and execute provide the best discrimination among groups. Post hoc analyses revealed that poor scores on simple tests of attention obtained in childhood were associated with the development of disorders in adulthood. Low scores on a digit cancellation test at age 11, but not at age 17, predicted which of the children at genetic risk would develop schizophrenia spectrum disorders diagnosed at ages 26 and 32.

Reanalysis of SCOR and anxiety measures in the Israeli High-Risk Study.

In an earlier study, skin conductance orienting response (SCOR) and anxiety measures obtained when the subjects of the Israeli High-Risk Study were 11 years old were analyzed, using adult diagnostic information, when the subjects were 26 years old. The present study considers similar data obtained from most of this sample when the subjects were 16 years old. As in the earlier analysis, those subjects who would receive a schizophrenia spectrum diagnosis at 26 had higher anxiety ratings at age 16. Nondiagnosed index subjects also had significantly higher anxiety ratings than the nondiagnosed controls. The subjects who would receive affective spectrum diagnoses at age 26 had the most hyporesponsive SCORs, as predicted, while the subjects who would later be diagnosed in the schizophrenia spectrum had an unexpected hyperresponsive SCOR to the dishabituation tone in a habituation series. Further consideration of the long-term stability of SCORs seems necessary; they may be related to the developing psychopathological processes.

Twenty-five-year followup of the Israeli High-Risk Study: current and lifetime psychopathology.

Current and lifetime psychopathology was assessed in 50 Israeli children of parents with schizophrenia who were either of kibbutz families and raised collectively with the help of child care workers, or of urban families and raised by their parents. Index subjects were compared with 50 matched control children of healthy parents by means of the Schedule for Affective Disorders and Schizophrenia-Israel. Subjects were evaluated in adulthood at a mean age of 31 years; schizophrenia was found exclusively among children of ill parents, and no effect of town or kibbutz rearing on risk for schizophrenia was observed. Major affective illness was more common among kibbutz index subjects. Affective symptomatology observed in some index parents was evenly distributed among town and kibbutz parents and was not related to the diagnosis of affective disorders in at-risk children. Current adult functioning was similar between town-and kibbutz-raised subjects (and in general reflected good adjustment); an excess of personality disorders was found among index subjects. The present findings support the concept that both familial and environmental factors operate in the expression of psychopathology.