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PubMed1999

Visuospatial priming and stroop performance in patients with obsessive compulsive disorder.

Two laboratory measures of competitive information processing were studied in obsessive compulsive disorder (OCD) and normal control participants to assess the effects of priming and interfering information on response latency or speed. In the visuospatial priming (VSP) task, key press latency is facilitated or inhibited, depending on the spatial location of a priming cue. In the Stroop task, participants name the ink color of printed words that have an interfering semantic value. OCD participants displayed significantly slowed baseline response latency and increased facilitory priming scores in the VSP task, with no significant difference in VSP inhibition compared with control participants. Higher interference cost in the Stroop task was also observed in OCD participants. Clinical associations between VSP and Stroop performance and specific OCD symptoms were examined. Increased VSP facilitation was most pronounced in OCD participants who reported a history of violent images, tics, "just right" obsessions, or checking compulsions.

Adult↗
PubMed1995

Optometric correlates of Meares-Irlen syndrome: a matched group study.

People who report visual perceptual distortions, typically when reading, that are alleviated by using coloured filters are described as suffering from 'Meares-Irlen Syndrome'. A recent double-masked placebo-controlled trial showed that this condition cannot be solely explained as a placebo effect and that the beneficial filter is idiosyncratic and sometimes needs to be highly specific. Several mechanisms have been suggested for Meares-Irlen Syndrome including ocular motor (binocular and accommodative) anomalies, a sensitivity to patterned stimuli (pattern glare), and a deficit of the transient visual sub-system. We investigated these hypotheses by comparing 16 children, who reported the symptoms described above and who showed a sustained benefit from coloured filters, with 25 control children who came from the same school and were matched for age, reading performance and intelligence. The 'Meares-Irlen Syndrome' group had slightly, but significantly, reduced vergence and accommodative amplitudes and stereo-acuity; they also demonstrated significantly more pattern glare. The two groups did not differ significantly in their visual acuities, refractive error, dissociated or associated heterophoria, AC/A ratio, or ability to perceive 20 Hz flicker. It appears that certain ocular motor factors are correlates of Meares-Irlen Syndrome, rather than the primary underlying cause of the symptoms. The results support the hypothesis that pattern glare may be involved in the mechanism of Meares-Irlen Syndrome.

Accommodation, Ocular↗
PubMed1997

[Reliability of family reports of illness anamnesis of schizophrenic patients].

Because a valid psychiatric history is difficult to obtain from an acute psychotic patient, particularly upon first admission, information given by important others is necessary for diagnostic classification, but the validity of this data must be examined. Within the ABC Schizophrenia Study, the onset and early course of schizophrenia was assessed from 171 post-psychotic first admissions and their close relatives. High agreement was found for substance abuse, self-destructive behaviour, paranoid delusion and social role deficits. Agreement was low for unspecific symptoms like depression, anxiety, problems with concentration or sleep. Due to a lack of sensitivity of the relatives' reports, agreement was also low for formal thought and perceptual disorders and derealization. A second study with 30 patients with schizophrenia and with 2 or more relatives for each case (n = 69) demonstrated that the quality of relatives' reports depends primarily on the relative's image of the patient (e.g., perceived dominance) and on the relative's attributions about the cause of the disease. Close and long contact tends to impair the quality of reports. Again, the observation of different symptoms is influenced differently by these factors.

Adolescent↗
PubMed1982

[Psychosomatic correlations in pediatric ophthalmology].

Somatopsychic disturbances encompassing both ophthalmologic as well as child-psychiatric phenomena mainly occur in ADD: Central disorders of eye motoricity (strabismus) and disorders of visual perception are encountered. Dyslexia or dysorthography often occur as secondary phenomena. The psychosomatic or psychogenic disturbances affect not only the lid mechanism but also visualization. In the lid region, nictation tics and trichotillomania of the eyebrows and eyelashes occur. Psychic impairment of vision may range from a slight amblyopia, often associated with limitation of the field of vision, to complete amaurosis. The symptomatology is described and illustrated with examples.

Adolescent↗
PubMed2005

Increasing reading speed by using colours: issues concerning reliability and specificity, and their theoretical and practical implications.

By using techniques for precision ophthalmic tinting, individuals who report perceptual distortion of text can often find a colour of illumination that eliminates the distortions and increases reading speed. Most individuals choose green or blue hues, but there is considerable variability. We investigated how specific the colour has to be to obtain optimal reading speed. Individuals who habitually wear coloured filters for reading were asked to read text illuminated by coloured light (without using their filters). Reading speed was measured repeatedly with light of different colours. The colour (chromaticity) at which reading was fastest was consistent from one test session to the next. It was different from one individual to another, but highly specific for each individual: departures of colour from optimum by about 6 JNDs eliminated most of the speed advantage conferred by the optimal colour. It was difficult to attribute the consistency and specificity simply to familiarity with the tint or immediate memory for the colour of illumination. A consecutive sample of 1000 tint prescriptions was analysed numerically. For most prescriptions the variation in chromaticity with different types of lighting was not such as to remove all the potential benefit of the tint, as judged from a model of the effect of chromaticity on reading speed. The exceptions were the few tints that were weakly saturated or purple in colour. Across participants, reading speed was not consistently related to the scotopic energy, to the energy captured by any cone class, or to opponent colour processes. The reading was generally slowest with white light, and not with the colour complementary to the optimum. Explanations in terms of magnocellular deficits and cortical hyperexcitability are briefly discussed.

Adolescent↗
PubMed1992

Implicit knowledge: new perspectives on unconscious processes.

Recent evidence from cognitive science and neuroscience indicates that brain-damaged patients and normal subjects can exhibit nonconscious or implicit knowledge of stimuli that they fail to recollect consciously or perceive explicitly. Dissociations between implicit and explicit knowledge, which have been observed across a variety of domains, tasks, and materials, raise fundamental questions about the nature of perception, memory, and consciousness. This article provides a selective review of relevant evidence and considers such phenomena as priming and implicit memory in amnesic patients and normal subjects, perception without awareness and "blindsight" in patients with damage to visual cortex, and nonconscious recognition of familiar faces in patients with facial-recognition deficits (prosopagnosia). A variety of theoretical approaches to implicit/explicit dissociations are considered. One view is that all of the various dissociations can be attributed to disruption or disconnection of a common mechanism underlying conscious experience; an alternative possibility is that each dissociation requires a separate explanation in terms of domain-specific processes and systems. More generally, it is concluded that rather than reflecting the operation of affectively charged unconscious processes of the kind invoked by psychodynamic or Freudian theorists, dissociations between implicit and explicit knowledge are a natural consequence of the ordinary computations of the brain.

Amnesia↗
PubMed2002

Congenital hypothyroidism: an analysis of persisting deficits and associated factors.

Congenital hypothyroidism (CH) is a neonatal disorder that is caused by a prolonged loss of thyroid hormone, which is essential for early brain development. While CH was once the leading cause of mental retardation, newborn screening for CH now allows for early identification and treatment. As a result, affected children now show normal physical and psychological development. Nevertheless, because they still undergo a brief but circumscribed period of thyroid hormone insufficiency, they are at risk for subtle selective impairments. This paper examines several of the persisting deficits observed in children with CH that was identified early in life by newborn screening as well as the relevant disease- and treatment-related factors contributing to such deficits. Highlighted will be (a) a weakness in visuospatial processing, which is associated with prenatal thyroid hormone insufficiency, (b) selective memory deficits associated with postnatal thyroid hormone insufficiencies, (c) a weakness in sensorimotor abilities also reflecting postnatal thyroid hormone insufficiencies, and (d) attention deficits, which are due to abnormal thyroid hormone levels at time of testing. Because these four disabilities implicate different neural substrates, the findings described presently will provide insights as to the specific time windows when different brain structures in the human critically need thyroid hormone.

Attention Deficit Disorder with Hyperactivity↗
PubMed1999

Is there a syndrome of tuberothalamic artery infarction? A case report and critical review.

Short-term post-acute neuropsychological, neurological, and neuroradiological test results and a 16-month follow-up of a 65-year-old patient with a right hemisphere ischemic lesion in the tuberothalamic area of vascular supply are reported. During a 6-week period of examinations the originally left- but trained right-handed patient exhibited fluctuating neuropsychological disorders including aphasia, visuo-perceptive and visuoconstructive disorders, and memory and attention deficits. In the follow-up examination the patient exhibited no aphasia and significant improvements in most neuropsychological tasks. Based on three-dimensional reconstruction of MRI, lesion topography and involvement of thalamic nuclei were established. We discuss the neuropsychological and neurological symptoms of the present case against the background of the 'syndrome of unilateral tuberothalamic artery territory infarction' proposed by Bogousslavsky and coworkers (1986) and the neuropsychological literature on unilateral ischemic anterior/anterolateral thalamic infarction.

Aged↗
PubMed2003

Relation of neurological soft signs to nonverbal memory performance in obsessive-compulsive disorder.

Few studies have examined the relation between neurological soft signs (NSS) and neuropsychological performance in Obsessive-Compulsive Disorder (OCD). Thirty outpatients with primary OCD and 30 matched normal controls were administered the Cambridge Neurological Inventory and the Rey-Osterrieth Complex Figure Test (RCFT). A series of multiple regression models tested the relationship between NSS and performance on the RCFT. Patients presented significantly more neurological soft signs than controls on both sides of the body, and were impaired on the free recall and organization scores of the RCFT. Nonverbal memory deficits in OCD were predicted independently by organizational strategies during the copy condition of the RCFT, and neurological soft signs. There might be at least two variables independently mediating nonverbal memory deficits in OCD: (1) a cognitive organization and planning component, and (2) a complex motor regulatory component.

Adult↗
PubMed2001

Visual and tactile size distortion in a patient with right neglect.

One typical feature of the neglect syndrome in patients with right hemisphere damage is that they bisect horizontal lines to the right of centre. It has been argued that to a large extent these bisection errors can be attributed to a perceptual change whereby the patient experiences the left half of a line as shorter than the right half, causing them to set the midpoint of the line towards the right. We describe here a patient with a left hemisphere lesion and rightward neglect, who consequently makes bisection errors in a leftward direction. We carried out a series of tests which confirmed that he shows a subjective visual distortion in the converse direction, i.e. a perception of horizontal extents on the right as shorter than extents on the left. We also found that he shows a similar distortion in his tactile perception. The association of visual and tactile distortions in this patient is compatible with the view that the distortion effects have a rather high-level origin. Multiple single-case studies will, however, be required to establish whether this association of deficits is typical, or whether visual and tactile size distortions are separable symptoms associated with neglect.

Attention↗
PubMed2003

Line bisection task performance and resting EEG alpha power.

Neurologically normal subjects generally err to the left of veridical center when performing a line bisection task, a phenomenon termed "pseudoneglect." We hypothesized that resting electroencephalogram (EEG) alpha oscillations may show relationships with attentional mechanisms and give some clues about the underlying mechanisms of pseudoneglect. We recorded resting EEGs of 41 subjects and tested them with a paper-pencil line bisection task. Our results showed that line bisection scores of men (n=18) were less biased and their performance was higher compared to those of women (n=20), but these differences only approached significance. The eyes open resting EEG alpha power of women was significantly and positively correlated with their line bisection performance. In general, significant relationships were related to the left hand performance when the lines were presented in the left hemispace. Greater resting alpha power was correlated with lower absolute bisection score or, in other words, higher bisection performance. Greater alpha power also correlated with diminished leftward bisection bias (or reduced pseudo-neglect). The resting EEG alpha of men was weakly associated with bisection performance. Results discussed in terms of Kinsbourne's activation-orientation theory and Basar's view on brain oscillations.

Adult↗
PubMed1999

Self awareness: effects of feedback and review on verbal self reports and remembering following brain injury.

Brain injury may produce impairments in self awareness. The magnitude of impairment is often determined by comparing patient self reports with self reports of others (report-report) or with patient performance (report-performance). This paper presents data on the pattern of a self-awareness deficit in memory functioning exhibited by a brain injury survivor 5 years post-injury. The effects of practice and feedback on reporting-recall differences was examined using single case methodology. Several prospective and retrospective self reports were obtained, to allow an examination of reporting about past or future recall. Results showed that recall improved and the magnitude of report-recall differences were reduced with practice and feedback.

Adult↗
PubMed2005

Extent, profile and specificity of visuospatial impairment in obsessive-compulsive disorder (OCD).

Recent reviews on the neurocognitive profile of patients diagnosed with obsessive-compulsive disorder (OCD) have converged on the assumption that both visuospatial and especially nonverbal memory performance are impaired in OCD. However, as most prior studies have contrasted performance of OCD patients with healthy controls only, no inferences can yet be drawn about the specificity of these deficits to OCD. Further, the administration of complex and multifunctional tasks limit conclusions about clearly defined cognitive deficits. The present study compared 71 OCD patients to 30 healthy and 33 psychiatric control participants on a large battery of visuospatial and nonverbal memory tasks at two time-points. In addition, a visuospatial battery (VS battery), which assesses a wide range of elementary visuospatial functions, was administered. While OCD patients performed worse than healthy controls on some complex tasks (e.g., Block Design), no visuospatial component proved to be impaired specifically in OCD. OCD patients and controls performed similarly on parameters of nonverbal memory. Regarding organizational strategy, OCD patients performed worse than healthy (but not psychiatric) control participants on two out of three Rey-figure trials (copy and immediate). It is suggested that prior research overestimated the severity and significance of visuospatial and nonverbal memory impairment in OCD.

Adult↗
PubMed2005

Do panic-agoraphobics overestimate distances?

Twenty-five subjects suffering from Panic Disorder with agoraphobia (PDA) and 25 normal controls (NC) were asked to estimate distances of familiar places of their town and non-distance stimuli. PDA subjects also completed the Mobility Inventory for Agoraphobia (MIA). Subjects with PDA significantly overestimated distances as compared to NC, whereas no significant difference was found on estimates of non-distance stimuli. Within the PDA group, significant correlations were found between distance estimates and subsets of MIA concerning the ways of moving through the environment. Although with caution, given the small sample size and the preliminary character of this study, the results could be interpreted as consistent with a cognitive dysfunction associated with PDA, probably at the level of representational mechanisms of the extrapersonal space.

Adult↗
PubMed2005

Virtual reality in brain damage rehabilitation: review.

Given the high incidence of brain injury in the population, brain damage rehabilitation is still a relatively undeveloped field. Virtual reality (VR) has the potential to assist current rehabilitation techniques in addressing the impairments, disabilities, and handicaps associated with brain damage. The main focus of much of the exploratory research performed to date has been to investigate the use of VR in the assessment of cognitive abilities, but there is now a trend for more studies to encompass rehabilitation training strategies. This review describes studies that have used VR in the assessment and rehabilitation of specific disabilities resulting from brain injury, including executive dysfunction, memory impairments, spatial ability impairments, attention deficits, and unilateral visual neglect. In addition, it describes studies that have used VR to try to offset some of the handicaps that people experience after brain injury. Finally, a table is included which, although not an exhaustive list of everything that has been published, includes many more studies that are relevant to the use of VR in the assessment and rehabilitation of brain damage. The review concludes that the use of VR in brain damage rehabilitation is expanding dramatically and will become an integral part of cognitive assessment and rehabilitation in the future.

Attention Deficit Disorder with Hyperactivity↗
PubMed1991

Perception and action in 'visual form agnosia'.

A single case study of a patient with 'visual form agnosia' is presented. A severe visual recognition deficit was accompanied by impairments in discriminating shape, reflectance, and orientation, although visual acuity and colour vision, along with tactile recognition and intelligence, were largely preserved. Neuropsychological and behavioural investigations have indicated that the patient is able to utilize visual pattern information surprisingly well for the control of hand movements during reaching, and can even read many whole words, despite being unable to make simple discriminative judgements of shape or orientation. She seems to have no awareness of shape primitives through Gestalt grouping by similarity, continuity or symmetry. It is proposed that many of these perceptual disorders might be the combined result of (1) a selective loss of the cortical elaboration of the magnocellular visual processing stream, and (2) a selective output disconnection from a central processor of visual boundaries and shape primitives in the occipital cortex.

Adult↗