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Biomedical subjects

R Campbell

Publications and source records attributed to R Campbell.

At least 19 recordsLinked to original sources
PubMed1992

The neuropsychology of lipreading.

Lipreading presents a unique glimpse of the intersection of sensory processes with modular, cognitive ones. It presents speech to the eye in an automatic and natural way, whether performed silently or in conjunction with heard speech. It therefore allows us to examine closely claims concerning the relation between input modality and cognitive function. In this paper I consider some of the ways in which the investigation of single neuropsychological cases casts light on this; such cases show us that lipreading can dissociate from other aspects of face perception and recognition, and from auditory speech perception and reading, too. Furthermore, different cognitive components of lipreading itself can be inferred from dissociations on different lipreading tasks. This leads to closer consideration of the boundaries of the necessary cognitive (and possibly anatomical) structures that subserve these functions.

Brain↗
PubMed1992

Optic aphasia with spared action naming: a description and possible loci of impairment.

A brief functional description is given of an optic aphasic patient, A.G., who shows a pure and isolated deficit in naming visually presented objects on confrontation, but with sparing of visual action names. We show how some tasks related to imagery are compromised in this patient and speculate on possible functional site(s) of impairment in terms of the routes from perception to naming. We suggest why action naming may be spared in such cases.

Anomia↗
PubMed1992

Psychosocial and psychopathologic influences on management and control of insulin-dependent diabetes.

The objective of this research was to explore the relationship of psychosocial variables to management and control of insulin-dependent diabetes, as measured by a scale of reported behavioral adherence and by glycosylated hemoglobin, respectively. The method includes a relatively large sample (127 subjects) drawn from a clinic, a broad range of psychosocial variables (depression, anxiety, family process, health locus of control), and documented reliability and validity of psychosocial measurement (alpha coefficients ranging from .63 to .95). The results show that both anxiety and depression have weak positive correlations with blood sugar. Family process variables also are weakly correlated with blood sugar. The measure of behavioral adherence is moderately correlated with blood sugar. The life stage of the diabetic appears to affect these relationships markedly. The conclusion is that there is no broad strong association of psychosocial variables with blood sugar but that there may be subgroups of diabetics, especially adolescents with recent onset, for whom the relationships may be more powerful.

Adolescent↗
PubMed1992

Initial experience of laparoscopic cholecystectomy in a district hospital.

Fifty-five consecutive unselected patients were submitted for laparoscopic cholecystectomy, and the procedure completed laparoscopically in fifty cases. The outcome is presented with particular reference to the duration of surgery, postoperative pain and nausea, the length of hospital stay and the time taken to recover normal activities. This technique is shown to have major advantages over conventional gallbladder surgery for the majority of patients.

Adult↗
PubMed1991

A fifteen year follow-up of a case of developmental prosopagnosia.

The term developmental prosopagnosia refers to an impairment in the recognition of familiar faces which has been present from birth in the absence of neurological disease or birth complications. The first reported study was by McConachie (1976, Cortex, 12: 76-82) and we report here a fifteen year follow-up on this case (AB). Recently developed theoretical models postulating separate processes involved in face perception and recognition were used to guide the exploration of her functional deficit. Our investigations with AB showed that basic visuo-sensory functions (acuity, contrast sensitivity, colour, etc.) were largely intact. General face perception (e.g. distinguishing between a face and a "nonface") was relatively well preserved. Recognition of familiar faces was severely impaired and she also showed problems with other face processing tasks (e.g. analysis of facial expression) and in object recognition. In object recognition she made errors based on visual similarity, and she had problems identifying exemplars from categories with many visually similar items. In addition, she was very poor at identifying objects or silhouettes from an unusual viewpoint. We conclude that AB has always been poor at constructing an effective internal representation sufficient to permit recognition of items which are visually difficult to discriminate. Therefore, she may not have been able to acquire useable stored representations either, because this deficit has been present since birth. This functional account was supported by subsequent studies which demonstrated a complete absence of covert face recognition.

Agnosia↗
PubMed1991

Neuropsychological function in young children who have undergone liver transplantation.

Presented neuropsychological data from 20 patients between the ages of 4 and 9 years, who had undergone liver transplantation at least 12 months prior to study participation, and compared them to a control group of 20 children with cystic fibrosis. The liver transplant group showed deficits in VIQ, PIQ, visual-spatial and abstraction/reasoning skills, but not in alertness/concentration, motor, or sensory-perceptual functions. On motor and sensory-perceptual tests, no differences were found in direction of lateralization of deficits. Visual-spatial deficits found in this study sample are similar to those found in adults with end-stage liver disease and in a previous report of an overall older group of children following liver transplantation. However younger children have greater evidence of generalized impairment and VIQ deficits which have not been found in older groups. Findings are discussed in relation to possible etiology, location of brain damage, and clinical implications.

Brain Damage, Chronic↗
PubMed1990

Neuropsychological studies of auditory-visual fusion illusions. Four case studies and their implications.

A heard speech sound which is not the same as the synchronized speech sound can sometimes give rise to an illusory phonological percept. Typically, a heard /ba/ combines with a seen /ga/ to give the impression that /da/ has been heard (McGurk, H. and MacDonald, J. Nature Lond. 264, 746-748, 1976). We report the susceptibility to this illusion of four individuals with localized brain lesions affecting perceptual function. We compare their performance to that of ten control subjects and relate these findings to the efficiency of processing seen and heard speech in separate and combined modalities. The pattern of performance strongly suggests LH specialization for the phonological integration of seen and heard speech. The putative site of such integration can be effectively isolated from unilateral and from bilateral inputs and may be driven by either modality.

Adult↗
PubMed1979

Antiviral drops: comparative therapy of experimental herpes simplex keratouveitis.

The present, masked, controlled study compares the therapeutic efficacy of guttate 3% vidarabine, 0.1% idoxuridine, and 1% trifluridine in herpes simplex keratouveitis in rabbits. Vidarabine, whether given every hour, every two hours, or every three hours was significantly better than controls but significantly worse than idoxuridine or trifluridine. Trifluridine and idoxuridine were not significantly different from each other. Viral cultures taken at the end of the six-day treatment period were positive in the majority of all treatment groups except for the trifluridine group, which was 100% negative. Although previous studies have shown that vidarabine is very effective as an antiviral ointment, vidarabine drops are not as effective as guttate idoxuridine or trifluridine.

Animals↗
PubMed1979

Left-handers' smiles: asymmetries in the projection of a posed expression.

Asymmetries in the expression of a posed smile and in a relaxed facial expression were observed in 24 left-handers. Neither writing position nor familial sinistrality predicted the variance of the results. Left-handers were found to smile more with their left than right side of face; an asymmetry which had previously been observed in right-handers. If anything, left-handers' smiles were more asymmetric, though in the same direction, than right-handers. When relaxed, however, the left-handers' face was judged more unhappy on its right than left side--a reversal of the direction of asymmetry previously noted in right-handers' relaxed expressions. No single neurological or psychological theory accounts for these results; it is suggested that hand preference may exert a myotonic effect which is reflected in judgements of relaxed facial expressions.

Adolescent↗
PubMed1979

Glycine and experimental spinal spasticity.

Spasticity may result in part from segmental spinal disinhibition. We determined the content and specific activity of glycine (the putative neurotransmitter thought to mediate spinal postsynaptic inhibition) and serine (the probable precursor of glycine) in feline spastic spinal cord following the intra-aortic administration of two labelled precursors of glycine--14C-D-glucose and 14C-L-serine. The specific activities of both glycine and serine were significantly reduced in the ventromedial, central, and dorsal spinal gray matter in spastic animals. Glycine content remained at control values but serine content increased in spastic spinal cord. This study suggests that glycine turnover decreases in spasticity, owing to its diminished release, and supports neurophysiologic evidence of a decrement in postsynaptic inhibition.

Animals↗
PubMed1979

Scoliosis and hydrocephalus in myelocele patients. The effects of ventricular shunting.

Developmental scoliosis is a common cause of increasing disability and deformity in long-term myelocele survivors, and is believed to result from a paralytic collapsing spine. The possible etiological role of compensated hydrocephalus and hydromyelia was assessed by determining the effect of ventricular shunting on 11 myelocele patients with developmental scoliosis. After successful shunting, one patient with a 47 degrees curve continued to deteriorate. Three cases with curves greater than 60 degrees were stabilized for short periods, but eventually required spinal fusion. Seven cases with curves less than 55 degrees were improved from a mean scoliosis of 29 degrees to 13 degrees during a 20-month follow-up period. Several patients had pre-existing shunts that were found to be non-functional on shuntogram. These findings suggest that the spinal complications of hydrocephalus may be more common than previously recognized in myelocele patients and that advanced developmental scoliosis may be avoided by early recognition and ventricular shunting.

Adolescent↗
PubMed1978

IgG2a-producing variants of an IgG2b-producing mouse myeloma cell line.

12 variant cell lines producing an IgG2a (kappa) immunoglobulin derived via different routes from the IgG2b (kappa) synthesizing MPC 11 were studied. These variants all have the parental MPC 11 idiotype as shown by a radioimmunoassay. A comparison of the variants by charge, peptide maps, and assembly patterns has shown that most of them differ from one another, and some can be grouped. One group consists of three primary variants generated with two mutagenic agents: these three have almost indistinguishable peptide maps. Two other primary variants which arose in a similar fashion differ markedly from each other and from this group. A second group is comprised of the four secondary variants which arose from two short heavy chain producing primary variants. Other secondary variants and the one spontaneously arising variant cannot be grouped. Possible genetic mechanisms such as translocation, expression of previously silent genes and recombination are discussed.

Cell Line↗
PubMed1978

Acyclic antimetabolite therapy of experimental herpes simplex keratitis.

In a masked controlled study we compared 3% acycloguanosine, 0.5% idoxuridine, and 3% vidarabine ointments in therapy of experimental herpes simplex virus keratitis in rabbits. The results of the acycloguanosine group were significantly better than the control groups and both other treatment groups, while producing none of the toxic side effects of increasing iritis, conjunctivitis or stromal keratitis, with continued drug application.

Animals↗