51
|
Sellen AJ, Louie G, Harris JE, Wilkins AJ. What brings intentions to mind? An in situ study of prospective memory. Memory 1997; 5:483-507. [PMID: 9282220 DOI: 10.1080/741941433] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In a naturalistic study, we aimed to uncover the relationship between thinking about and remembering intentions. Electronic badges allowed us to track the activities of subjects within their work environment. Over two weeks, subjects were asked to respond using a button on their badges (1) every two hours (Time task); (2) whenever they were in a particular room (Place task). In addition, whenever they thought about the task, they were asked to indicate this with their badges. Although subjects thought about the Time task more, they forgot to respond more often than in the Place task. In the Time task, there was a marked absence of thoughts about the task following successful remembering. When subjects remembered the Place task, thoughts increased with proximity to the target location. In both tasks, thoughts about intentions occurred more in places such as stairwells than in locations where people tended to settle. On the basis of these findings, possible mechanisms for prospective memory are discussed.
Collapse
|
52
|
Wilkins AJ. Photograph was insensitive. West J Med 1997. [DOI: 10.1136/bmj.314.7096.1765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
53
|
Chen EY, Lam LC, Chen RY, Nguyen DG, Chan CK, Wilkins AJ. Neuropsychological correlates of sustained attention in schizophrenia. Schizophr Res 1997; 24:299-310. [PMID: 9134590 DOI: 10.1016/s0920-9964(96)00120-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We employed a simple and relatively undemanding task of monotone counting for the assessment of sustained attention in schizophrenic patients. The monotone counting task has been validated neuropsychologically and is particularly sensitive to right prefrontal lesions. We compared the performance of schizophrenic patients with age- and education-matched controls. We then explored the extent to which a range of commonly employed neuropsychological tasks in schizophrenia research are related to attentional impairment as measured in this way. Monotone counting performance was found to be correlated with digit span (WAIS-R-HK), information (WAIS-R-HK), comprehension (WAIS-R-HK), logical memory (immediate recall) (Weschler Memory Scale, WMS), and visual reproduction (WMS). Multiple regression analysis also identified visual reproduction, digit span and comprehension as significant predictors of attention performance. In contrast, logical memory (delay recall) (WMS), similarity (WAIS-R-HK), semantic fluency, and Wisconsin Card Sorting Test (perseverative errors) were not correlated with attention. In addition, no significant correlation between sustained attention and symptoms was found. These findings are discussed in the context of a weakly modular cognitive system where attentional impairment may contribute selectively to a range of other cognitive deficits.
Collapse
|
54
|
Wilkins AJ, Jeanes RJ, Pumfrey PD, Laskier M. Rate of Reading Test: its reliability, and its validity in the assessment of the effects of coloured overlays. Ophthalmic Physiol Opt 1996; 16:491-7. [PMID: 8944196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A simple reading test that can be undertaken by disabled readers is described. The test is suitable for use in the optometric clinic, taking less than 2 minutes to administer per passage. Test-retest scores are acceptably reliable. The test reveals increases in the speed of reading when coloured overlays are used both (1) in children who have made long-term use of coloured overlays for reading, and (2) in children who will subsequently do so.
Collapse
|
55
|
Wilkins LT, Wilkins AJ. Rationing health care. US judicial guidelines on sentencing could show way forward for NHS. BMJ (CLINICAL RESEARCH ED.) 1996; 313:558. [PMID: 8789994 PMCID: PMC2351898 DOI: 10.1136/bmj.313.7056.558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
|
56
|
Evans BJ, Wilkins AJ, Brown J, Busby A, Wingfield A, Jeanes R, Bald J. A preliminary investigation into the aetiology of Meares-Irlen syndrome. Ophthalmic Physiol Opt 1996; 16:286-96. [PMID: 8796197 DOI: 10.1046/j.1475-1313.1996.95001190.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A recent double-masked placebo-controlled trial has confirmed that some children experience a reduction in symptoms of eyestrain and headache when they read through individually prescribed coloured filters and has shown that this benefit cannot be solely attributed to a placebo effect. People who are helped by coloured filters in this way have been described as having "Meares-Irlen syndrome'. We investigated the mechanism of this benefit by studying the optometric and visual perceptual characteristics of the children in the double-masked study. This population had normal refractive errors and heterophorias (none of the subjects had strabismus). They demonstrated slightly, but significantly, reduced amplitudes of accommodation and vergence and poor stereo-acuity. However, these factors seemed to be correlates of Meares-Irlen syndrome rather than the underlying cause. Pattern glare, a sensitivity to striped patterns (e.g. lines of text), was prevalent in our sample and was significantly associated with the subjects' symptoms. The spatial contrast sensitivity function was normal.
Collapse
|
57
|
Chronicle E, Wilkins AJ. Gratings that induce perceptual distortions mask superimposed targets. Perception 1996; 25:661-8. [PMID: 8888299 DOI: 10.1068/p250661] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Masking is known to depend upon the relationship between the spatial-frequency content of target and mask. This relationship has been held constant in three experiments in order to investigate the separate contribution of the spatial parameters of the mask, in this case a grating with square-wave luminance profile. Thresholds for the detection of a probe target were highest when the background grating upon which the probe was superimposed had a spatial frequency of about 4 cycles deg-1 (experiment 1) and a duty cycle of 50% (experiment 3). In experiment 2, the thresholds were strongly affected by the size of the background grating even though the size of the target was small in proportion to the grating and remained constant. The increase in threshold was linearly related to the area of visual cortex to which the grating projected. The spatial parameters of gratings that maximise masking are therefore the same as those that have been shown to be optimal for the induction of perceptual distortions, suggesting a possible physiological mechanism for both the masking and the distortions.
Collapse
|
58
|
Evans BJ, Busby A, Jeanes R, Wilkins AJ. Optometric correlates of Meares-Irlen syndrome: a matched group study. Ophthalmic Physiol Opt 1995; 15:481-7. [PMID: 8524579 DOI: 10.1046/j.1475-1313.1995.9500063j.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
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.
Collapse
|
59
|
Chronicle EP, Wilkins AJ, Coleston DM. Thresholds for detection of a target against a background grating suggest visual dysfunction in migraine with aura but not migraine without aura. Cephalalgia 1995; 15:117-22. [PMID: 7641245 DOI: 10.1046/j.1468-2982.1995.015002117.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Square-wave gratings with particular spatial characteristics induce visual illusions. Patients with migraine are particularly susceptible to these illusions and report discomfort. Their discomfort tends to be greater when the gratings are illuminated by red light, a tendency not shown by controls. Gratings that induce illusions have been found to impair the recognition of optically superimposed targets in headache-free control subjects. We measured the impairment of target detection under illuminants of various chromaticities in migraineurs with and without aura and in matched controls. Migraineurs with aura had significantly higher thresholds for target detection than either migraineurs without aura or controls; in addition, the effect of chromaticity was slightly more pronounced in both migraine groups than in the control group. These findings are consistent with a recent suggestion that migraine with aura might give rise to subclinical damage to the primary visual cortex.
Collapse
|
60
|
Wilkins AJ, Evans BJ, Brown JA, Busby AE, Wingfield AE, Jeanes RJ, Bald J. Double-masked placebo-controlled trial of precision spectral filters in children who use coloured overlays. Ophthalmic Physiol Opt 1994; 14:365-70. [PMID: 7845693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We selected 68 children who reported benefit from individually chosen sheets of coloured plastic placed upon the page when reading, and who used these regularly without prompting. These children viewed text illuminated by coloured light in an apparatus that allowed the separate manipulation of hue (colour) and saturation (depth of colour), at constant luminance. Many of the children reported improvements in perception when the light had a chromaticity within a limited range, which was different for each individual. A pair of plastic spectacle lenses ('experimental' lenses) was dyed so as to provide the appropriate chromaticity under conventional white (F3) fluorescent light. An additional pair was prepared having very similar colour but with a chromaticity outside the range in which perception was reported to improve ('control' lenses). Each pair was provided for 1 month in random order. The children kept diaries (36 completed) recording symptoms of eye-strain and headache. The children and those responsible for their assessment were unable reliably to distinguish 'experimental' from 'control' lenses. Nevertheless, symptoms were less frequent on days when the 'experimental' lenses were worn (P < 0.003).
Collapse
|
61
|
Abstract
The integrity of semantic memory in schizophrenia was examined in a reaction time task requiring subjects to verify words as members or non-members of a conceptual category, where the words differed in their degree of semantic relationship to the category. Compared to matched normal controls, 28 schizophrenic patients were impaired on the task, showing slower responses in all conditions. In addition, their performance was anomalous in that they took longest to respond to items that were outside the category but semantically related to it, in contrast to the controls who took the longest to respond to ambiguous words at the borderline of the category. The pattern of 'yes' and 'no' responses of the patients was anomalous in a similar way. In both speed and accuracy of responding, the findings indicate that there is an outward shift of semantic category boundaries in schizophrenia.
Collapse
|
62
|
Wilkins AJ, Nimmo-Smith I, Jansons JE. Colorimeter for the intuitive manipulation of hue and saturation and its role in the study of perceptual distortion. Ophthalmic Physiol Opt 1992; 12:381-5. [PMID: 1454378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A simple optical method for mixing coloured light is described. The observer has intuitive and approximately independent control over hue and saturation at constant brightness. The method facilitates colour matching by unpracticed observers. It allows children with reading difficulties to select a colour that reduces perceptual distortion of text. The chromaticity coordinates of this colour vary from one observer to another but can be very specific. Complementary colours can exacerbate the distortions and induce pain. For the majority of children reporting beneficial perceptual effects, the u' coordinate is less than 0.25.
Collapse
|
63
|
Wilkins AJ, Nimmo-Smith I, Jansons JE. Colorimeter for the intuitive manipulation of hue and saturation and its role in the study of perceptual distortion. Ophthalmic Physiol Opt 1992. [DOI: 10.1111/j.1475-1313.1992.tb00413.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
64
|
Smith AP, Tyrrell DA, Barrow GI, Higgins PG, Bull S, Trickett S, Wilkins AJ. The common cold, pattern sensitivity and contrast sensitivity. Psychol Med 1992; 22:487-494. [PMID: 1319599 DOI: 10.1017/s0033291700030427] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Results from two studies involving challenge with respiratory syncytial viruses showed that volunteers who developed colds were more sensitive to a visually distracting pattern presented prior to virus challenge than were volunteers who did not get a cold. Volunteers with sub-clinical infections reported more illusions after virus challenge than they had done before, whereas uninfected volunteers and those with colds tended to report fewer illusions on the second test. These effects did not occur when volunteers were challenged with either a coronavirus or rhinovirus. Overall, the results confirm that behavioural measures may be related to susceptibility to subsequent illness, and that viral infections may influence visual perception. They also show that the effects vary according to the nature of the infecting agent, which agrees with results from studies looking at other aspects of behaviour.
Collapse
|
65
|
|
66
|
Wilkins AJ, Wilkinson P. A tint to reduce eye-strain from fluorescent lighting? Preliminary observations. Ophthalmic Physiol Opt 1991; 11:172-5. [PMID: 2062542 DOI: 10.1111/j.1475-1313.1991.tb00217.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The rapid modulation of light from fluorescent lamps is responsible for eye-strain and headaches. The modulation is greater at certain wavelengths than at others, and it can therefore be reduced by wearing tinted spectacles. A tint was designed: (1) to minimize the luminous pulsation of light from conventional halophosphate fluorescent lamps; (2) to avoid as much as possible any concomitant increase in the pulsation from triphosphor lamps; (3) to interfere with colour perception as little as possible; and (4) to have a cosmetically acceptable colour appearance. The four design criteria conflict. A compromise design is described, together with case histories of patients who appear to have benefited from the use of the tint.
Collapse
|
67
|
Abstract
Under three types of artificial lighting 24 women with chronic agoraphobia and 24 female control subjects assessed their mood and bodily symptoms, and their heart rate was measured. One of the three types of lighting was incandescent. The other two were fluorescent, one pulsating in the conventional manner 100 times per second and the other relatively steady. Both were provided by a single fluorescent lamp controlled from one of two circuits. When exposed to the conventional pulsating fluorescent light under double-blind conditions the agoraphobic group showed a higher heart rate and reported more anomalous visual effects in response to an epileptogenic pattern. Control subjects reported more bodily symptoms under the conventional fluorescent light than under the two other lighting conditions.
Collapse
|
68
|
Vernon JM, Wilkins AJ. Anaesthesia and medium-chain acyl CoA dehydrogenase deficiency. Br J Hosp Med (Lond) 1990; 43:328. [PMID: 2364223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
69
|
Abstract
Three studies examine the role that provocative visual stimuli have in eliciting anxiety reactions in people with agoraphobia. Such stimuli elicit more anxiety in agoraphobic patients than control subjects. The effect of visual stimulation appears to be specific: (1) non-visual stimulation is without comparable effect; (2) both control and agoraphobic groups show similar effects of visual stimulation on another reaction such as headache. The anxiety effects of visual stimuli are correlated with the extent to which subjects experience depersonalization and somatic symptoms of agoraphobia, but not correlated with depression or the behavioural or cognitive aspects of agoraphobia. Alternative accounts of the possible role of visual stimulation in the anxiety reactions of agoraphobic patients are discussed.
Collapse
|
70
|
Neary C, Wilkins AJ. Effects of phosphor persistence on perception and the control of eye movements. Perception 1989; 18:257-64. [PMID: 2771610 DOI: 10.1068/p180257] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
When a rapid eye movement (saccade) is made across material displayed on cathode ray tube monitors with short-persistence phosphors, various perceptual phenomena occur. The phenomena do not occur when the monitor has a long-persistence phosphor. These phenomena were observed for certain spatial arrays, their possible physiological basis noted, and their effect on the control of eye movements examined. When the display consisted simply of two dots, and a saccade was made from one to the other, a transient ghost image was seen just beyond the destination target. When the display consisted of vertical lines, tilting and displacement of the lines occurred. The phenomena were more intrusive for the latter display and there was a significant increase in the number of corrective saccades. These results are interpreted in terms of the effects of fluctuating illumination (and hence phosphor persistence) on saccadic suppression.
Collapse
|
71
|
|
72
|
Abstract
Fifteen persons who admitted to chronic worry were asked to complete morning and evening diaries in which they reported the occurrence of headaches, assessed their mood, and observed a visually stressful pattern, noting the illusions it induced. Results showed an association between both trait and state measures of mood and headache occurrence, and between trait and state measures of headache occurrence and illusion susceptibility. However, mood and illusion susceptibility did not appear themselves to be associated either as trait or state variables. The implications of these results for remediation of headaches are discussed.
Collapse
|
73
|
Della Sala S, Comi G, Martinelli V, Somazzi L, Wilkins AJ. The rapid assessment of visual dysfunction in multiple sclerosis. J Neurol Neurosurg Psychiatry 1987; 50:840-6. [PMID: 3625206 PMCID: PMC1032120 DOI: 10.1136/jnnp.50.7.840] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A consecutive series of patients with normal activity and a diagnosis of multiple sclerosis (10 male and 31 female) underwent extensive ophthalmological examination including visual evoked potentials (VEPs) and a new test of contrast sensitivity, which is described in detail. Seventy three per cent of patients had abnormal contrast sensitivity and 83% had abnormal VEPs. There was no association between abnormalities of the two types, but patients who had impaired contrast sensitivity and normal VEPs were younger than those whose contrast sensitivity was normal but whose VEPs were not. The test of contrast sensitivity (which took less than 5 minutes to administer) was the only examination to reveal visual abnormalities in all nine patients with a history of optic neuritis, and would be a useful supplementary test in the examination of patients with suspected multiple sclerosis.
Collapse
|
74
|
Binnie CD, Kasteleijn-Nolst Trenité DG, Smit AM, Wilkins AJ. Interactions of epileptiform EEG discharges and cognition. Epilepsy Res 1987; 1:239-45. [PMID: 3504400 DOI: 10.1016/0920-1211(87)90031-3] [Citation(s) in RCA: 127] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Interactions of subclinical epileptiform EEG discharges and cognitive functioning were studied in 91 patients with epilepsy, under video monitoring, to exclude overt clinical ictal phenomena during the investigations. A short-term memory test was presented as an engaging television game, in two versions, using spatial, or verbal material. Transitory cognitive impairment (TCI) was demonstrated during EEG discharges, either generalised or focal, in half the patients. Right-sided discharges were associated with impairment of the spatial task and left-sided with errors on the verbal version. TCI was demonstrable only when the discharge occurred during presentation of the material to be recalled. Increasing task difficulty, up to the patients' limit of performance, was associated with increasing susceptibility to TCI. Sixteen patients showed a significant effect of task on discharge rate, but in some this increased during the stimulus and in others while responding. There are thus complex interactions of epileptiform EEG activity on cognitive function and vice versa.
Collapse
|
75
|
Edwards RJ, MacDermot J, Wilkins AJ. Prostacyclin analogues reduce ADP-ribosylation of the alpha-subunit of the regulatory Gs-protein and diminish adenosine (A2) responsiveness of platelets. Br J Pharmacol 1987; 90:501-10. [PMID: 2436701 PMCID: PMC1917175 DOI: 10.1111/j.1476-5381.1987.tb11199.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Prostacyclin and adenosine activate adenylate cyclase in human platelet membranes and inhibit platelet aggregation. Results are presented which show that prolonged incubation of platelets with iloprost (a stable prostacyclin analogue) results in a reduction in the capacity for adenylate cyclase activation by the adenosine analogue 5'-(N-ethyl)-carboxamidoadenosine (NECA), NaF, guanyl-5'-yl imidodiphosphate or GTP. However, iloprost pretreatment resulted in no change in the binding of [3H]-NECA to platelet membranes. These results contrast with those obtained after pretreatment with 2-chloroadenosine which revealed no change in NaF or guanyl-5'-yl imidodiphosphate sensitivity of adenylate cyclase. Pretreatment with 2-chloroadenosine resulted in reduced NECA-dependent adenylate cyclase activation, and loss of [3H]-NECA binding sites. The heterologous desensitization of adenosine A2-receptors by iloprost is accompanied by a loss (greater than 80%) of a 45 kDa protein from the plasma membrane, as revealed by [32P]-ADP-ribosylation in the presence of cholera toxin. It is proposed that this example of heterologous desensitization is mediated by elimination of Gs alpha, a subunit of the stimulatory guanyl nucleotide-binding regulatory protein.
Collapse
|
76
|
Abstract
Neurological patients were presented with a succession of 2-11 stimuli which they were required to count, reporting the number in the series when it finished. The stimuli were binaural clicks, or pulses on the right or on the left index finger. Regardless of stimulus modality or lateralization, patients with lesions involving the right frontal lobe were impaired when the presentation rate was 1/sec. There was no corresponding impairment when the presentation rate was increased to 7/sec. It is argued that at slow rates when the task was monotonous patients with right-frontal lesions were less able than others to sustain attention voluntarily.
Collapse
|
77
|
Wilkins AJ. On the manner in which sensory and cognitive processes contribute to epileptogenesis, and are disrupted by it. ACTA NEUROLOGICA SCANDINAVICA. SUPPLEMENTUM 1986; 109:91-5. [PMID: 3465188 DOI: 10.1111/j.1600-0404.1986.tb04867.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
78
|
Wilkins AJ. Remembering to do things in the laboratory and everyday life. ACTA NEUROLOGICA SCANDINAVICA. SUPPLEMENTUM 1986; 109:109-12. [PMID: 3465185 DOI: 10.1111/j.1600-0404.1986.tb04869.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
79
|
Wilkins AJ, MacDermot J. The putative prostacyclin receptor antagonist (FCE-22176) is a full agonist on human platelets and NCB-20 cells. Eur J Pharmacol 1986; 127:117-9. [PMID: 2428638 DOI: 10.1016/0014-2999(86)90211-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The action of FCE-22176 on prostacyclin receptors of human platelets and the NCB-20 cell line have been examined. FCE-22176 is a full agonist in both systems, mediating activation of adenylate cyclase. The concentration required for half-maximum enzyme activation was 174 nM in platelet membranes and 193 nM in homogenates of NCB-20 cells. The binding of [3H]iloprost to human platelet or NCB-20 cell membranes was inhibited by FCE-22176, and Ki values of 400 and 280 nM were obtained.
Collapse
|
80
|
Alt U, Leigh PJ, Wilkins AJ, Morris PK, MacDermot J. Desensitization of iloprost responsiveness in human platelets follows prolonged exposure to iloprost in vitro. Br J Clin Pharmacol 1986; 22:118-9. [PMID: 2427097 PMCID: PMC1401073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
|
81
|
Darby CE, Park DM, Smith AT, Wilkins AJ. EEG characteristics of epileptic pattern sensitivity and their relation to the nature of pattern stimulation and the effects of sodium valproate. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1986; 63:517-25. [PMID: 2422001 DOI: 10.1016/0013-4694(86)90139-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Seven patients with pattern-sensitive epilepsy were examined repeatedly over a period of 4-12 months during which the dose of sodium valproate was adjusted. Patterns were presented in series in which the size of successive patterns was progressively increased until paroxysmal activity appeared, or until the largest pattern (radius 24 degrees visual angle) had been presented. As valproate dose increased, paroxysmal activity was less likely to occur. When it did occur it was less likely to include a spike; it had a lower voltage, involved fewer electrodes, and lasted a shorter time. The size of the pattern just sufficient to induce paroxysmal activity showed relatively little change with valproate dose. The degree to which the various electrodes were involved in the discharges showed considerable stability. The paroxysmal response to patterns presented in one visual half-field was almost invariably maximal over the contralateral posterior quadrant, usually at the posterior temporal electrode.
Collapse
|
82
|
Della Sala S, Somazzi L, Wilkins AJ. Rapid technique for detecting "blurred vision" in diseases of primary visual pathways. Lancet 1985; 2:1015-6. [PMID: 2865491 DOI: 10.1016/s0140-6736(85)90568-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
83
|
Binnie CD, Findlay J, Wilkins AJ. Mechanisms of epileptogenesis in photosensitive epilepsy implied by the effects of moving patterns. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1985; 61:1-6. [PMID: 2408857 DOI: 10.1016/0013-4694(85)91065-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The triggering of epileptiform EEG discharges by pattern is thought to depend on the intensity of excitation within the visual cortex. The present study investigates the role of the synchronisation of neuronal activity by the stimulus. In 10 pattern-sensitive subjects the effects of the following patterns have been compared: (1) static gratings, (2) gratings oscillating in a direction orthogonal to the lines (which should synchronise activity in direction-sensitive cortical units), and (3) gratings drifting at the same angular velocity (which should produce little or no synchronisation, because the contours enter and leave the overlapping receptive fields of individual neurones asynchronously). The oscillating gratings were most, and the drifting least, epileptogenic. In 2 further subjects oscillating and phase-reversing patterns were more epileptogenic than drifting gratings. Although open to alternative explanations, the findings conform with predictions from the hypothesis that synchronisation of individual cortical neurones by the stimulus contributes to epileptogenesis in photosensitive subjects.
Collapse
|
84
|
|
85
|
Della Sala S, Bertoni G, Somazzi L, Stubbe F, Wilkins AJ. Impaired contrast sensitivity in diabetic patients with and without retinopathy: a new technique for rapid assessment. Br J Ophthalmol 1985; 69:136-42. [PMID: 3967001 PMCID: PMC1040540 DOI: 10.1136/bjo.69.2.136] [Citation(s) in RCA: 114] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A simple technique is described for assessing the sensitivity of the human visual system to gratings at threshold contrast. The technique has advantages for clinical use in that it is (1) inexpensive, (2) quick to administer, (3) portable, and (4) relatively free from bias. Forty-two diabetic patients and 84 normal controls have been tested. Fifteen diabetic patients (6/20 with retinopathy and 9/22 without) had test scores more than two standard deviations below the norm for age-matched controls.
Collapse
|
86
|
Abstract
The offence of attempted infanticide has hitherto been unknown in English Law. A case is here described in which a woman was convicted of infanticide, and attempted infanticide, having been charged with murder and attempted murder. The relevance of this is discussed, together with an aspect of infanticide previously unreported in the English literature, i.e. repetition of the offence.
Collapse
|
87
|
Aarts JH, Binnie CD, Smit AM, Wilkins AJ. Selective cognitive impairment during focal and generalized epileptiform EEG activity. Brain 1984; 107 ( Pt 1):293-308. [PMID: 6421454 DOI: 10.1093/brain/107.1.293] [Citation(s) in RCA: 355] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
It is well established that generalized epileptiform EEG discharges unaccompanied by overt clinical change may nevertheless be associated with transitory cognitive impairment (TCI) detectable by appropriate psychological testing. However, the tests employed in most research studies of this phenomenon are of little use for routine clinical application. They are suitable for administration only over short periods of time and are therefore applicable only to patients with a high discharge rate, a serious limitation, as the discharges are generally depressed by the tests themselves. We have developed two short-term memory tasks, one using verbal, the other nonverbal material presented in the form of television games which patients are generally prepared to perform for up to an hour or longer. Forty-six patients with subclinical EEG discharges have been studied. They were screened by video monitoring before and during testing to exclude any with overt clinical changes during the discharges. Despite this rigorous selection, in 50 per cent TCI was demonstrable with a confidence level (within the individual patient) of 10 per cent. Discharges during stimulus presentation were most disruptive of performance and those confined to the period when the patient was responding were without demonstrable effect. A significant association was found between the laterality of focal or asymmetrical generalized discharges and impairment of one or other task, left-sided discharges being associated with errors in the verbal task and right-sided with impairment of the nonverbal test. Two case histories are cited illustrating patients who were clearly handicapped by TCI and whose functioning improved when the subclinical discharges were suppressed by medication. To determine how many patients suffer such disabilities or can be helped by appropriate medication, further prospective studies are required.
Collapse
|
88
|
Wilkins AJ, Jenkins WJ, Steiner JA. Efficacy of clonidine in treatment of alcohol withdrawal state. Psychopharmacology (Berl) 1983; 81:78-80. [PMID: 6415735 DOI: 10.1007/bf00439278] [Citation(s) in RCA: 79] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Clonidine hydrochloride 5 micrograms/kg and placebo were given orally to 11 patients experiencing well-developed alcohol withdrawal states. Active drug and placebo were given in a randomised, cross-over double blind fashion 2 h apart. Clonidine significantly suppressed heart rate (P = 0.002), arterial blood pressure (P = 0.006), and an accumulated score of withdrawal symptoms and signs (P = 0.004). These data suggest that clonidine may be useful in the management of alcohol withdrawal states, and that the underlying pathophysiology of at least some of these manifestations may be sympathetic nervous system hyperactivity.
Collapse
|
89
|
Wastell DG, Wilkins AJ, Darby CE. Self-induction of epileptic seizures by eye-closure. Spectral analysis of concomitant EEG. J Neurol Neurosurg Psychiatry 1982; 45:1151-2. [PMID: 6819341 PMCID: PMC491701 DOI: 10.1136/jnnp.45.12.1151] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The spectral characteristics of the EEG were studied in the period immediately preceding slow eye-closures associated with the self-induction of epileptiform activity. Power levels were compared with similar spontaneous eye-closures not associated with paroxysmal activity, with eye closures performed to command, and with EEG preceding eye-blinks. A transient rise in EEG power at low frequencies 1-2 seconds before the slow eye-closure was found to be reliably associated with the subsequent occurrence of paroxysmal activity. This finding suggests that eye-closure may not be initial event in the sequence culminating in paroxysmal activity.
Collapse
|
90
|
Abstract
A patient with generalized convulsions noted that seizures were reliably precipitated by mental arithmetic. The interictal electroencephalogram revealed only a mild, diffuse, nonspecific disturbance, but bursts of generalized epileptiform activity with no obvious clinical expression accompanied efforts at mental arithmetic with a significantly high incidence. Tasks involving multiplication, division, and manipulation of spatial information were significantly associated with discharges, but few, if any, discharges appeared when addition and subtraction tasks of equivalent difficulty were performed. Tasks involving the retention of numerical information in short-term memory (e.g., immediate repetition of a series of 8 digits) were never associated with paroxysmal EEG activity. It is argued that generalized epilepsy of this kind may be related to focal dysfunction in a manner analogous to the involvement of the occipital lobe in cases of pattern-sensitive epilepsy.
Collapse
|
91
|
Wilkins AJ, Binnie CD, Darby CE. Interhemispheric differences in photosensitive epilepsy. I. Pattern sensitivity thresholds. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1981; 52:461-8. [PMID: 6171412 DOI: 10.1016/0013-4694(81)90030-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A group of 15 volunteers with both photosensitive epilepsy and pattern sensitivity were shown patterns of stripes in the left and right visual hemifields. In the majority of patients the resulting paroxysmal epileptiform EEG activity was maximal in the posterior temporal and occipital regions contralateral to the stimulus. Patterns in the upper and lower hemifields were also presented and in two patients there was a difference in the vertical distribution of the response such as to suggest that in these patients the discharges were largely confined to the striate and prestriate cortex. The probability with which paroxysmal activity was evoked was usually different for the two lateral hemifields. This difference between the hemifields (which was dramatic in some patients) was mirrored in a lateralisation of the responses to diffuse intermittent photic stimulation. The association between the asymmetries in pattern sensitivity and in the responses to photic stimulation suggests that the two cerebral hemispheres often differed in hyperexcitability. It is therefore interesting that the putative differences in hyperexcitability were observed in patients with primary generalised epilepsy as well as those with other types.
Collapse
|
92
|
Binnie CD, Wilkins AJ, De Korte RA. Interhemispheric differences in photosensitive epilepsy. II. Intermittent photic stimulation. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1981; 52:469-72. [PMID: 6171413 DOI: 10.1016/0013-4694(81)90031-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Of a consecutive series of 138 photosensitive epileptic patients 57 showed a unilateral preponderance of asymmetrical discharges on IPS, significant in each individual at the 5% level. There was no association between asymmetry of IPS-induced discharges and clinical evidence of cerebral pathology (partial or secondary generalized epilepsy, neurological deficit, left handedness, etc.). It is concluded that these results, together with our previous findings of asymmetrical pattern sensitivity suggest that the cortical hyperexcitability postulated in primary cortico-reticular epilepsy is not uniformly distributed.
Collapse
|
93
|
Wilkins AJ, Rose D, Hartley J, Sloboda JA, Brown J. Review: The Story of Ruth, Behavioural Neuroscience: An Introduction, NATO Conference Series, Series III, Volume 13. Processing of Visible Language 2, Human Memory: Structures and Processes (Second Edition). Perception 1981. [DOI: 10.1068/p100355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
94
|
Binnie CD, Darby CE, De Korte RA, Veldhuizen R, Wilkins AJ. EEG sensitivity to television: effects of ambient lighting. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1980; 50:329-31. [PMID: 6160975 DOI: 10.1016/0013-4694(80)90161-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The effect of ambient lighting on EEG sensitivity to television has been tested in 16 photosensitive epileptic patients. Those who were not sensitive to 50 Hz IPS responded to TV at a viewing distance of 1 m or less and showed a consistent increase of EEG activation by television when the room was brightly lit. Most of those who were sensitive to 50 Hz IPS were also TV-sensitive at viewing distances greater than 1 m and the effect was most marked with lights off. The results are discussed in the context of previous work showing that some patients with TV epilepsy respond to the raster pattern of the screen and some, at greater distance, to 50 Hz flicker.
Collapse
|
95
|
Binnie CD, Darby CE, De Korte RA, Wilkins AJ. Self-induction of epileptic seizures by eyeclosure: incidence and recognition. J Neurol Neurosurg Psychiatry 1980; 43:386-9. [PMID: 7420087 PMCID: PMC490563 DOI: 10.1136/jnnp.43.5.386] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Self-induction of epileptic seizures is generally regarded as a rarity, chiefly observed in patients of subnormal intelligence. During EEG recordings with open eyes in a consecutive series of 48 photosensitive patients, however, 13 subjects induced paroxysmal activity of seizures by eyeclosure with forced upward deviation of the eyes. Eyeclosure on command produced a different type of oculographic artefact and induced paroxysmal activity in only one subject. Two patients were of subnormal intelligence but all displayed psychiatric or psychosocial problems. The incidence of induced paroxysmal activity was reduced by reduction of ambient lighting. Eight patients admitted self-induction of seizures. We conclude that this phenomenon occurs more often than was previously supposed and can be recongnized by the recording in photosensitive patients of prolonged EEGs with eyes open and in a brightly lit environment.
Collapse
|
96
|
Abstract
Of 22 consecutive epileptic patients sensitive to intermittent photic stimulation, 7 were found to induce paroxysmal activity and/or seizures by a slow closure of the lids accompanied by eye rolling, which in 6 of the 7 was totally different from the movement normally carried out on voluntary eye closure to command. To identify the syndrome it may be necessary to monitor the EEG and oculogram for some 10 min or longer with the eyes open in a well-lit environment.
Collapse
|
97
|
|
98
|
Wilkins AJ, Darby CE, Binnie CD, Stefansson SB, Jeavons PM, Harding GF. Television epilepsy--the role of pattern. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1979; 47:163-71. [PMID: 95710 DOI: 10.1016/0013-4694(79)90218-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Patients with photosensitive epilepsy were asked to view normally functioning 625-line televisions while the EEG was monitored. In the first of two studies paroxysmal EEG activity was reliably induced by television at a viewing distance related to a patient's sensitivity to intermittent photic stimulation (IPS); patients who were sensitive to diffuse IPS at 50 Hz were sensitive to the television at greater viewing distances than those who were not. No such relationship was obtained with patterned IPS. On the other hand, patterned IPS was generally more epileptogenic than diffuse IPS with the same luminance. In the second study, where the angular subtense of the television screen and the subtense of its lines were manipulated independently, the convulsive response was found to be a function of both factors, the relative contribution of each depending on the viewing distance at which the patient was sensitive. For patients sensitive at normal viewing distances, where 50 Hz diffuse flicker appeared to be responsible for the induction of paroxysmal activity, the probability with which paroxysmal activity was induced was closely related to the subtense of the screen. For patients sensitive only at closer viewing distances the probability was influenced not by the subtense of the screen but by the subtense of its lines, suggesting that the paroxysmal activity was induced by the 25 Hz pattern alternation produced by the scan. A television with a small screen was considerably less epileptogenic than one with a large screen for all patients, presumably due to the reduced contribution of both diffuse flicker and pattern alternation.
Collapse
|
99
|
Worcester NA, Bruckdorfer KR, Hallinan T, Wilkins AJ, Mann JA, Yudkins J. The influence of diet and diabetes on stearoyl Conenzyme A desaturase (EC 1.14.99.5) activity and fatty acid composition in rat tissues. Br J Nutr 1979; 41:239-52. [PMID: 34420 DOI: 10.1079/bjn19790033] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
1. Rats were given low-fat diets for 3 d in which the carbohydrate source was starch. The livers of animals given the fructose or sucrose had increased hepatic activities of the fatty acid synthetase and stearoyl CoA desaturase (EC 1.14.99.5) enzyme complexes: in those given fructose there was a lower activity of the enzymes in adipose tissue. 2. Similar results were obtained in rats given fructose diets for 30 d, but in animals which had previously been made diabetic with streptozotocin, the activities were lower. The dietary treatment made little difference to the fatty acid profiles of the tissue lipids. The diabetic condition on the other hand produced considerable changes in fatty acid profile. 3. With diets containing approximately 200 g fat/kg in the form of butter or of polyunsaturated margarine, the tissue lipids from rats given sucrose had less linoleic acid than those from rats given starch. In addition, there was the expected difference between the rats given butter or margarine. The results are discussed in relation to the current literature.
Collapse
|
100
|
Abstract
The capacity of striped patterns (square-wave gratings) to induce paroxysmal EEG activity in a group of pattern-sensitive epileptic patients is shown to depend on: 1. The spatial frequency of the pattern. The optimum spatial frequency lies between 1 and 4 cycles/degree in every patient tested. 2. The orientation of the pattern. Although, for the patient group as a whole, no one orientation is consistently more likely to induce paroxysmal activity than any other, the responses of individual patients can show marked orientation selectivity. 3. The brightness contrast of the pattern. The probability of paroxysmal EEG activity increases dramatically as contrast is increased from 0.2 to 0.4. Red/green gratings at isoluminance fail to induce paroxysmal activity. 4. The size of the pattern. There is considerable variation between patients in the subtense of a centrally-fixated circular pattern necessary to induce paroxysmal activity with a given probability. However, for every patient an increase in the probability of paroxysmal activity from near zero to near unity is effected by an increase in the angular subtense of the pattern by a factor of two. Patterns other than square-wave gratings are capable of inducing paroxysmal activity but, in general, patterns that stimulate more than one orientation system are less epileptogenic. The above findings are compatible with the hypothesis of a seizure trigger in the striate cortex and are incompatible with a trigger confined to the lateral geniculate nucleus of the thalamus. Further evidence against a geniculate trigger is obtained from an investigation of the response of a pattern-sensitive patient to a diffuse (unpatterned) flickering field in which it is shown that the effects of counter-phase interocular flicker implicate binocular mechanisms.
Collapse
|