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PubMed2004

Distance underestimation in virtual space is sensitive to gender but not activity-passivity or mode of interaction.

Four groups of undergraduates (half of each gender) experienced a movement along a corridor containing three distinctive objects, in a virtual environment (VE) with wide-screen projection. One group simulated walking along the virtual corridor using a proprietary step-exercise device. A second group moved along the corridor in conventional flying mode, depressing a keyboard key to initiate continuous forward motion. Two further groups observed the walking and flying participants, by viewing their progress on the screen. Participants then had to walk along a real equivalent but empty corridor, and indicate the positions of the three objects. All groups underestimated distances in the real corridor, the greatest underestimates occurring for the middle distance object. Males' underestimations were significantly lower than females' at all distances. However, there was no difference between the active participants and passive observers, nor between walking and flying conditions.

Adolescent↗
PubMed2000

A systematic study of visual extinction. Between- and within-field deficits of attention in hemispatial neglect.

Mechanisms of visual extinction were investigated in four patients with right hemisphere damage using a partial report paradigm. Different shapes (star or triangle) were displayed in one, two or four possible locations so that double simultaneous stimuli occurred either across the two hemifields or within the same hemifield. Patients attended either to the location (right, left or both), number (one, two or four) or shape (no, one or two stars among the shapes presented) of stimuli in three separate experiments using the same displays and exposure duration. Reporting the location (Experiment 1) produced marked contralesional extinction, although reaction time was delayed compared with unilateral right trials, indicating unconscious processing. Reaction time was also delayed on correct bilateral and unilateral left trials. In contrast, enumerating stimuli (Experiment 2) caused no significant contralesional extinction on bilateral displays and reaction time was similar on bilateral and unilateral right trials, suggesting that information from both fields was grouped in a single numerable percept in this task. However, patients often detected only one of two stimuli within the left field. Whereas similarity of shapes improved localization and did not affect enumeration, identifying stars among shapes (Experiment 3) revealed a severe inability to detect two similar targets between hemifields as well as within each of the hemifields. Distracting triangles were generally less detrimental to the perception of a concurrent target on either side, but slowed the reaction time regardless of whether they were in the same or the opposite field. Relative difficulty in ignoring distractors correlated with neglect severity on a cancellation task, and was most prominent in one patient with a large amount of frontal damage. These findings suggest that (i) allocation of attention to identical stimuli can be modulated by task demand; (ii) enumerating a small set of items across fields may not require attending to individual stimuli but relies on preattentive subitizing ability, as found in normal subjects; (iii) location information may be critical for attentional mechanisms subserved by the parietal cortex and pathological competition for awareness in extinction; (iv) extinction entails a bilateral deficit in attending to two concurrent similar targets when their features must be identified; and (v) the relevance of the stimuli can modulate the distribution of attention, possibly through frontal top-down control. These findings are consistent with recent neurophysiological evidence of parietal and frontal attentional influences on ventral visual pathways.

Aged↗
PubMed1998

False recognition effects in young and older adults' memory for text passages.

Recent work has demonstrated an age-related increase in susceptibility to illusory memories; specifically, older adults make more false recognition responses to unstudied items when such items are semantically related to studied items. The majority of studies have examined false recognition for semantically associated words; the current study extends that previous work by examining false recognition effects for schematized story actions. In two experiments young and older adults studied schematized stories and were later given a recognition test for studied and unstudied story actions. Our results indicate that both age groups produced robust false recognition effects, but older adults were not more susceptible to these effects. These results suggest there are limits to the range of circumstances that yield age differences in illusory memories.

Adolescent↗
PubMed2000

The effect of aging on adaptive eye-hand coordination.

Perceptual-motor adaptability of older adults (65 and older) was assessed. Participants in two groups (younger, 20-36 years, and older, 67-87 years) pointed 100 times at a straight-ahead visual target while looking through laterally displacing prisms, with the hand visible early in the pointing movement. Aftereffect tests were administered after adaptation. Each group was then split into decay and readaptation subgroups in which respective treatments were given twice. After each treatment, aftereffect tests were readministered. Eye-hand total shift was significantly smaller for older participants, proprioceptive shift was not statistically smaller for older participants, and visual shift did not appear. Readaptation produced greater reduction in aftereffects than did decay; this effect was the same for both groups. The main conclusion is that perceptual-motor adaptability declines with advancing age.

Adult↗
PubMed1999

Structured Interview for Assessing Perceptual Anomalies (SIAPA).

Clinical descriptions of perceptual and attentional anomalies in schizophrenia emphasize phenomena such as flooding, or inundation, by sensory stimuli. A failure of sensory "gating" mechanisms in the brain is hypothesized to account for these symptoms, and this hypothesis has led to a marked interest in their putative psychophysiological substrates. However, there are no systematic analyses of the phenomenology of these perceptual experiences, nor has the hypothesized connection between the clinical phenomena and their reported psychophysiological substrates been tested. In this investigation, a structured interview instrument was developed to measure perceptual anomalies as distinct from hallucinations and to determine their prevalence across sensory modalities in schizophrenia in 67 schizophrenia subjects and 98 normal controls. The instrument includes Likert ratings of hypersensitivity, inundation, and selective attention to external sensory stimuli. Good interrater agreement, determined from interviews, was obtained. Schizophrenia subjects had significantly higher auditory, visual, and combined scores (i.e., across all modalities) than normal controls did, indicating significantly more perceptual anomalies. For the schizophrenia group, the prevalence of auditory and visual anomalies was significantly greater than the other sensory modalities. The data indicate that the putative phenomenological correlates of sensory gating may be reliably measured and tested with the Structured Interview for Assessing Perceptual Anomalies.

Adult↗
PubMed1994

Psychometric high-risk paradigm, perceptual aberrations, and schizotypy: an update.

The psychometric high-risk strategy represents a useful methodologic adjunct to the traditional genetic high-risk research approach in the study of the etiology and development of schizophrenia. During the past 15 years, considerable research activity has focused on psychometrically identified individuals hypothesized to be en route to schizophrenia (i.e., putative schizotypes). The Perceptual Aberration Scale (PAS) has figured prominently in such prediction-oriented psychometric high-risk work. This report examines research using the PAS completed since 1987 that has established the instrument as a valid index for detecting liability for schizophrenia (or schizotypy) and as, arguably, the schizotypy index of choice for research. These results are presented and interpreted in light of Meehl's theoretical framework of schizotypy. Other measures of and assessment devices for schizotypy (schizophrenia-related liability) are identified. Of these other measures, the Chapmans' Magical Ideation Scale and the schizophrenia liability index of Moldin and colleagues are particularly well established. Methodologic suggestions for future psychometric high-risk and other work using objective measures of schizotypic psychopathology are offered. It is strongly recommended that future studies of schizotypy (or those in the planning stages, relying on psychometric detection methods use multiple psychometric indices to tap schizotypy or use a psychometric index in association with other promising biobehavioral markers of schizophrenia liability (e.g., sustained attentional deficits, eye movement dysfunction) for maximum efficiency in both location and definition of schizotypes.

Body Image↗
PubMed2006

Disturbances of time consciousness from a phenomenological and a neuroscientific perspective.

The subjective experience of time is a fundamental constituent of human consciousness and can be disturbed under conditions of mental disorders such as schizophrenia or affective disorders. Besides the scientific domain of psychiatry, time consciousness is a topic that has been extensively studied both by theoretical philosophy and cognitive neuroscience. It can be shown that both approaches exemplified by the philosophical analysis of time consciousness (Husserl) and the neuroscientific theory of cross-temporal contingencies (binding of cognitive processes over time) as the neurophysiological basis of human consciousness implemented in the prefrontal cortex (Fuster) converge in 2 respects. Firstly, a tripartite conception of consciousness divides human cognition in 3 different temporal domains comprising retention, presentation, and protention (Husserl) and the past, the present, and the future corresponding to working memory, interference control, and preparatory set (Fuster). Secondly, both concepts refer to the present as an extended duration that integrates information from the recent past and the future. We propose that the integration of phenomenological and neuroscientific approaches can stimulate the development of enriched pathophysiological concepts of mental disorders. This approach appears to be particularly fruitful with respect to schizophrenia that is interpreted as a structural disturbance of time consciousness.

Awareness↗
PubMedDate not supplied

Clinical considerations in the use of time-compressed speech.

The four lists of the Auditec of St. Louis recording of the 60% time-compressed NU 6 test were presented at 32 dB SL to 28 normal subjects and 28 subjects with sensorineural hearing loss. Significant list effects were found, with only lists I and IV being equivalent for both groups. A significant learning effect, greater for the normal subjects, also was present. Clinical recommendations are made regarding list and practice effects and considerations for use of this test in the presence of peripheral hearing impairment.

Adult↗
PubMedDate not supplied

Group amplification in schools for the hearing impaired.

In the present field study, ambient noise levels and the status of group FM-wireless amplification systems were examined in 19 classrooms for the hearing impaired. Classroom noise was judged to be unacceptably high thus justifying the need for group amplification devices. Physical inspection of the group systems revealed defects in approximately one-half of the 28 teacher and 89 student amplification units. The electroacoustic measurements showed wide variability in performance among systems. There also appeared to be no systematic relationship between the degree of hearing loss of the children and the amount of unit gain being employed by each specific amplification system.

Amplifiers, Electronic↗
PubMed1990

Dimensions of personality disorder. The DSM-III-R cluster A diagnoses.

The authors adopt a construct validity approach to examine the structural validity of diagnoses of paranoid, schizoid, and schizotypal personality disorders. Systematic descriptions of these diagnoses were developed based on features identified from the literature that were organized using the clinicians' ratings. Each diagnosis was described in terms of a series of behavioral dimensions. Sets of behavioral exemplars were developed to assess each dimension. Dimensions and diagnoses were found to exhibit satisfactory levels of internal consistency that were cross-validated in a general population sample of 274 subjects and a clinical sample of 133 patients with a diagnosis of personality disorder. Some dimensions did not correlate highly with the total diagnosis score. Diagnoses could probably be refined by eliminating these dimensions. The structural relationships between dimensions delineating each diagnosis were explored using factor analysis. Diagnoses were not unifactorial. Instead, each diagnosis was found to be composed of two factors. The factorial structure of each diagnosis was found to be similar in the general population and clinical sample. It is suggested that the results support a dimensional representation of these diagnoses using three dimensions: paranoid behaviors, social avoidance, and perceptual cognitive distortion.

Adult↗
PubMed1992

Toward a more culturally sensitive DSM-IV. Psychoreligious and psychospiritual problems.

In theory, research, and practice, mental health professionals have tended to ignore or pathologize the religious and spiritual dimensions of life. This represents a type of cultural insensitivity toward individuals who have religious and spiritual experiences in both Western and non-Western cultures. After documenting the "religiosity gap" between clinicians and patients, the authors review the role of theory, inadequate training, and biological primacy in fostering psychiatry's insensitivity. A new Z Code (formerly V Code) diagnostic category is proposed for DSM-IV: psychoreligious or psychospiritual problem. Examples of psychoreligious problems include loss or questioning of a firmly held faith, and conversion to a new faith. Examples of psychospiritual problems include near-death experiences and mystical experiences. Both types of problems are defined, and differential diagnostic issues are discussed. This new diagnostic category would: a) improve diagnostic assessments when religious and spiritual issues are involved; b) reduce iatrogenic harm from misdiagnosis of psychoreligious and psychospiritual problems; c) improve treatment of such problems by stimulating clinical research; and d) encourage clinical training centers to address the religious and spiritual dimensions of human existence.

Culture↗
PubMed2002

Future time perspective in pathological gamblers.

The hypothesis that pathological gambling is associated with shortened time horizons was investigated by administering the Zimbardo Time Perspective Inventory (ZTPI) and the Future Time Perspective Inventory (FPTI) to a group of pathological gamblers and two comparison groups, psychiatric day patients and social gamblers. The South Oaks Gambling Screen (SOGS) was used to assess the severity of the participants' gambling. Sixty-six participants were recruited, of which 35 were women. The mean age of participants was 39 years. Results showed significantly shorter time horizons in pathological versus social gamblers but few differences between pathological gamblers and psychiatric patients. These results suggest that shortened time horizons are not a unique feature of addicted populations. The role of psychological distress as a possible explanatory variable is discussed.

Adult↗