Healthcare Engineering Defined: A White Paper.

Engineering has been playing an important role in serving and advancing healthcare. The term "Healthcare Engineering" has been used by professional societies, universities, scientific authors, and the healthcare industry for decades. However, the definition of "Healthcare Engineering" remains ambiguous. The purpose of this position paper is to present a definition of Healthcare Engineering as an academic discipline, an area of research, a field of specialty, and a profession. Healthcare Engineering is defined in terms of what it is, who performs it, where it is performed, and how it is performed, including its purpose, scope, topics, synergy, education/training, contributions, and prospects.

Temporal lobe dysfunction and electrodermal nonresponding in schizophrenia.

The present study examined the biological correlates of electrodermal activity in 63 patients with DSM-III diagnosed chronic schizophrenia. Subjects were administered a battery of neuropsychological tests sensitive to temporal lobe, frontal lobe, and overall brain functioning. Brain morphology was evaluated by calculating the size of the lateral ventricles, measuring the width of the third ventricle, and rating the extent to which cortical sulci were visible. Electrodermal hyporesponsiveness was associated with impaired performance on tests that assessed temporal lobe functioning. No association was found between the brain morphology indices and electrodermal activity.

Season of birth and electrodermal activity in functional psychoses.

The present study examined the association between electrodermal activity (EDA) and season of birth in a sample of first-episode patients with schizophrenia, schizophreniform disorder, and affective disorder with psychotic features, and in a normal control group. Patients with schizophrenia who were born during the season of excess risk (January-April) were less responsive than those born during other times of the year. They had lower skin-conductance levels and fewer skin-conductance responses. No such effects were found in patients with schizophreniform or affective disorder, or in the normal subjects. When compared with the control group, winter-born schizophrenics showed significantly more evidence of hyporesponsivity. In contrast, nonwinter-born patients did not differ from normal subjects in skin-conductance level or number of skin-conductance responses. Schizophreniform patients born during the other seasons of the year were more likely to be hyporesponsive. The above results provide supporting evidence for the validity of the season of birth phenomenon. We hypothesize that a viral infection, or some other perinatal complication associated with winter and early spring births, leads to temporal lobe damage and consequent dysregulation of electrodermal activity in patients with schizophrenia.

Association of left-handedness with ventricle size and neuropsychological performance in schizophrenia.

Left-handed schizophrenic patients showed lateral ventricular enlargement and generally poorer performance on intelligence and neuropsychological tests compared with right-handed schizophrenic patients. These results suggest that left-handed schizophrenic patients have more cerebral dysfunction than right-handed schizophrenic patients.

Smooth pursuit ocular motor dysfunction in schizophrenia: evidence for a major gene.

OBJECTIVE: Evidence suggests that poor eye tracking relates to genetically transmitted vulnerability for schizophrenia. The authors tested competing models for the genetic transmission of poor eye tracking in a search for major gene effects. METHOD: Samples from three studies (conducted in Minneapolis, New York, and Vancouver, B.C.) were pooled. Probands (N = 92) were diagnosed as schizophrenic by DSM-III criteria. Of the comparison subjects (N = 171), Vancouver patients were an epidemiologic first-episode group; at other sites unselected admitted patients were studied. First-degree relatives (N = 146) of 65 probands were also studied. Eye tracking was measured while subjects followed a horizontally moving, sinusoidally driven (0.4 Hz) spot of light on a screen. Performance was quantified by root mean square error. Data analysis was by complex segregation analysis (Bonney's class D regressive models). RESULTS: A single major gene is needed to account for poor eye tracking in schizophrenic patients and their relatives. This gene alone can explain about two-thirds of the variance in eye tracking performance. A single gene alone (regardless of dominance) will, however, not account for the data; polygenic factors are also required. CONCLUSIONS: Results support postulation of a single gene for ocular motor dysfunction, which may be a risk factor for schizophrenia. Eye tracking may be useful as a gene carrier test in genetic studies of schizophrenia.

Verbal working memory impairment in schizophrenia patients and their first-degree relatives: evidence from the digit span task.

OBJECTIVE: The evidence for verbal working memory deficits in schizophrenia has been inconsistent. Few studies have evaluated verbal working memory in the first-degree relatives of schizophrenia patients, who likely share the genetic diathesis for schizophrenia but not the potential confounds associated with chronic mental illness. METHOD: The Wechsler Digit Span Task was used to investigate verbal working memory in 52 schizophrenia patients, 56 of their first-degree relatives, and 73 nonpsychiatric comparison subjects. RESULTS: The nonpsychotic relatives showed no impairment on the forward digit span task, a measure of general attention, but did show impairment on the backward digit span task, a measure of verbal working memory. Schizophrenia patients showed impairment on both the forward and backward digit span tasks. CONCLUSIONS: These results indicate that the forward and backward digit span tasks tap different cognitive abilities that are differentially associated with the diathesis for schizophrenia. Working memory deficits associated with schizophrenia appear to be generalized and not limited to the spatial modality.

Neuropsychological and oculomotor correlates of spatial working memory performance in schizophrenia patients and controls.

Recent reports of spatial working memory deficits in schizophrenia provide evidence for dorsolateral prefrontal cortical (DLPFC) dysfunction. However, the question of how spatial working memory performance relates to other task impairments in schizophrenia considered reflective of frontal dysfunction, such as the Wisconsin Card Sorting Test (WCST) and smooth pursuit eye tracking, has been largely unexplored. Spatial working memory, as measured by a computerized visual-manual delayed response task (DRT), was evaluated in 42 schizophrenia patients and 54 normal controls. Subjects also completed a battery of neuropsychological and oculomotor tasks. Schizophrenia patients performed as accurately as controls on a no-delay, sensory-motor control condition, but showed a significant impairment in spatial accuracy with the addition of an 8-s delay and verbal distraction task. For the patients, working memory impairment was associated with fewer categories on the WCST, impaired eye tracking, fewer words learned on the Rey Auditory Verbal Learning Test, but not with measures of general cognitive and clinical functioning. Results suggest the presence of a sub-group of schizophrenia patients with common pathophysiology that accounts for the co-variance of several tasks implicating prefrontal dysfunction.

Electrodermal activity and clinical status in chronic schizophrenia.

The present study investigated the association between electrodermal nonresponsiveness and clinical state in schizophrenia. Sixty-three patients with a DSM-III diagnosis of chronic schizophrenia served as subjects. Clinical status was assessed using multiple measures, including age of onset, symptom severity, illness duration, hospitalization history, global functioning, and occupational functioning. Electrodermal hypoactivity was found to be associated with poorer functioning and a more severe form of illness. In addition, hyporesponsive patients displayed more conceptual disorganization and alogia.

Clinical, neuropsychological, and brain structural correlates of smooth-pursuit eye tracking performance in chronic schizophrenia.

The relation of smooth-pursuit eye tracking dysfunction to neuropsychological performance, brain structural anomalies, and clinical state was examined in a sample of 61 patients with chronic schizophrenia. No association was found between impaired pursuit oculomotion and measures of chronicity or clinical state. Likewise, no association emerged between eye-tracking integrity and brain structural anomalies. Patients with dysfunctional eye tracking were more likely to have impaired performance on tests that assess frontal lobe functioning. In addition, negative symptoms and a relative absence of positive symptoms. Because negative symptoms are often found among patients with frontal lobe impairment, their association with abnormal eye tracking provides converging support for the hypothesis that the cortical locus of deviant smooth-pursuit eye tracking is in the frontal lobes.

Anhedonia and perceptual aberration in first-episode psychotic patients and their relatives.

One hundred eighteen psychiatric patients, each experiencing his or her first lifetime episode of psychosis, 125 of their first-degree relatives, and 155 normal subjects were assessed using the physical anhedonia, social anhedonia, and perceptual aberration scales of Chapman et al. (1976, 1978). We hypothesized that psychotic subjects would obtain higher scores on these scales than their relatives and the controls, and we expected the group of relatives to score more deviantly than the normal controls. The physical anhedonia and social anhedonia scales successfully differentiated the psychiatric patients from the relatives and the latter from the normal subjects. These findings testify to the construct validity of the scales and suggest that they tap a predisposition to psychosis. Unexpectedly, the relatives scored lower on the perceptual aberration scale than did the normal controls, perhaps because the relatives adopted a defensive response set.

Clinical correlates of anhedonia and perceptual aberration in first-episode patients with schizophrenia and affective disorder.

We examined the association between scales measuring physical anhedonia, social anhedonia, and perceptual aberration and premorbid functioning, clinical state, and current level of adjustment in 91 psychotic subjects. The patients were examined at the onset of their first psychotic episode and again 18 months later. For patients with schizophrenia, anhedonia was significantly related to premorbid functioning. No association was found between the scales and clinical state or level of adjustment at intake or follow-up. In affective disorder patients, no correlation was found between premorbid functioning (a stable characteristic) and scale scores, but moderately large correlations emerged between the scales and clinical state and level of adjustment at both assessment times. These results suggest that schizophrenic and affective disorder patients endorse items on these scales for different reasons. We hypothesize that for patients with schizophrenia, the scales assess enduring personality characteristics, whereas for the affective disorder patients, they assess clinical condition at the time of testing.

Antisaccade performance in patients with schizophrenia and affective disorder.

The authors examined psychotic patients with schizophrenia, major depression, and bipolar disorder; "normal" participants; and 1st-degree relatives of patients with schizophrenia on an antisaccade task in which participants were instructed to move their eyes in the opposite direction of a target that moved unpredictably and abruptly either to the left or right of central fixation. Patients with schizophrenia were found to make significantly more errors than their relatives, and the latter made more errors than the controls. The poor performance of the relatives could not be attributed to their having a psychiatric disorder. Comparison of the 3 patient groups indicated that antisaccade deficits were more pronounced in schizophrenia and bipolar disorder.

Psychometric detection of schizotypy: perceptual aberration and physical anhedonia in relatives of schizophrenics.

We administered scales of Perceptual Aberration (PERAB) and Physical Anhedonia (PHYSAN), traits that may be related to risk for schizophrenia, to 54 schizophrenics, 146 of their first-degree relatives (evaluated for schizophrenia-related disorders), and 178 normal subjects (screened for psychotic disorders in them or their relatives). For both scales, there was a significant effect of group membership. For the PERAB scale, the schizophrenics had higher scores than the normal subjects, who had higher scores than the relatives. For the PHYSAN scale, schizophrenics had higher scores than their relatives, who had higher scores than the normal subjects. Patterns of familial correlations also suggested that physical anhedonia, but not perceptual aberration, may be familial among schizophrenics and their relatives. The PHYSAN scale, but not the PERAB one, may be a useful indicator of liability for schizophrenia among the relatives of affected probands.

Effects of instructional set on attributions of nonvolition during hypnotic and nonhypnotic analgesia.

Fifty highly hypnotizable subjects were assigned to four treatment groups or a no-treatment control group and then underwent two pain stimulation trials. Half the treated subjects were administered hypnotic analgesia, half waking analgesia. Within hypnotic and nonhypnotic treatments, half the subjects were given actively worded analgesia instructions, half passively worded instructions. Subjects in the four treated groups reported equivalent pain reduction and equivalent use of coping imagery, although hypnotic subjects rated themselves as more deeply hypnotized than did nonhypnotic subjects. Both hypnotic and nonhypnotic subjects given passive instructions rated their pain reduction as occurring involuntarily, whereas those given active instructions reported that their pain was reduced through their active use of coping strategies. These findings support sociocognitive formulations of hypnotic responding that view ratings of involuntariness as reflecting contextually guided interpretations of behavior.

Emotional modulation of the startle reflex in twins: preliminary findings.

This study investigated twin similarity in general startle reflex reactivity and emotional modulation. Seventeen monozygotic (MZ) and 12 dizygotic (DZ) male twin pairs received startling acoustic stimuli while viewing emotionally positive, negative and neutral slides. Electromyographic (EMG) responses were recorded from the orbicularis oculi. Members of MZ twin pairs had similar response amplitudes under all three valence conditions. In addition, modulation scores for the positive and negative conditions, representing the percent change in response amplitude between the affective and the neutral conditions, also showed significant similarity within MZ twin pairs. Overall, members of DZ twin pairs were not found to be significantly similar of any of the measures. These preliminary findings suggest that emotional modulation of the startle reflex shows familial resemblance within MZ pairs. Given the lack of resemblance between DZ twins, it is tentatively suggested that affective modulation may be under partial genetic control.

Relationship of lateral ventricular size to psychophysiological measures and short-term outcome.

To examine clinical and psychophysiological correlates of lateral ventricular size, computerized tomographic (CT) scans were obtained on a sample of 88 patients who had experienced their first psychotic episode. Patients met DSM-III criteria for schizophrenia, schizophreniform disorder, or affective disorder with psychotic features. For patients with schizophrenia, large lateral ventricles were associated with unfavorable outcome. No association between outcome and ventricular size was found in patients with affective or schizophreniform disorder. Patients with mood disorders who had large ventricles consumed significantly greater amounts of alcohol than those with small ventricles. No differences were found between patients with large or small ventricles in premorbid functioning, smooth pursuit eye tracking, or electrodermal activity.

Eye-tracking performance and adaptive functioning over the short-term course of first-episode psychosis.

We examined the relationship of smooth pursuit eye tracking to the course of first-episode psychosis. Various measures of social, occupational, and psychological functioning were obtained for 134 persons with diagnoses of schizophrenia, schizophreniform disorder, or psychotic mood disorder at the time of their psychosis and 9 and 18 months later. Poor eye-tracking performance was associated with generally impaired functioning over the 18-month course of disorder for patients with schizophrenia. A similar association between smooth pursuit and adaptive functioning was not found in patients with schizophreniform or affective disorder. The results suggest that patients with schizophrenia who are characterized by poor eye tracking have a more severe disorder, indications of which are present at the onset of their psychosis.

The association between P300 and age from preadolescence to early adulthood.

The present study examined the latency and amplitude of P300 in a large sample of subjects between 11 and 21 years old. The P300 components of the visual event-related potential showed consistent and significant age-related changes. Peak amplitude was found to diminish with increasing age, whereas peak latency decreased. Our data indicate that a linear relationship best explains the association between age and P300 amplitude and latency. The changes in P300 amplitude and latency across the different ages are likely to reflect developmental changes in mental processing that are not due to a decrease in general cortical reactivity with increasing age or the result of subject noncompliance.

Visual event-related potentials in first-episode psychotic patients and their relatives.

We conducted a comprehensive examination of the sensory visual event-related potential (ERP) of psychiatric patients and their relatives using a methodology that improves upon those used previously by other investigators. One hundred thirty-five patients at the onset of their first psychotic episode, 146 first-degree relatives of these patients, and 113 normal controls were exposed to light flashes of four different intensities while their ERPs were recorded from three central scalp sites. For most analyses, various ERP amplitude measures did not discriminate the different psychiatric groups or their relatives either from one another or from the normal controls. These findings indicate that patients with schizophrenia, schizophreniform disorder, and affective disorder at the early stage of their illnesses do not display significant deficits in the processing and regulation of simple sensory visual stimulation.