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Dive into the research topics where Michael P. Clarke is active.

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Featured researches published by Michael P. Clarke.


Gut | 2002

Prevalence of faecal incontinence in adults aged 40 years or more living in the community.

Sarah Perry; Chris Shaw; C McGrother; Ruth Matthews; R. P. Assassa; H. Dallosso; K. Williams; Katherine Brittain; U Azam; Michael P. Clarke; Carol Jagger; C Mayne; C. M. Castleden

Background: Prevalence studies of faecal incontinence in the general population are rare and the impact of faecal incontinence on quality of life has not been previously addressed. Aims: To establish the prevalence of faecal incontinence in adults in terms of frequency of leakage, degree of soiling, and level of impact on quality of life. Methods: In a cross sectional postal survey, 15 904 adults aged 40 years or more (excluding residents of nursing and residential homes) were selected randomly by household from the Leicestershire Health Authority patient register. Participants were asked to complete a confidential health questionnaire. Major faecal incontinence was defined as soiling of underwear or worse with a frequency of several times a month or more. Respondents were also asked if bowel symptoms had an impact on their quality of life. Results: From a total sample of 10 116 respondents, 1.4% reported major faecal incontinence and 0.7% major faecal incontinence with bowel symptoms that had an impact on quality of life. Major faecal incontinence was significantly associated with a lot of impact on quality of life (odds ratio 12.4, 95% confidence interval 7.5–20.6). Incontinence was more prevalent and more severe in older people but there was no significant difference between men and women. Conclusions: This study has confirmed that faecal incontinence is a fairly common symptom, particularly in older people. Faecal incontinence in men has received little attention in the past and the results from this study indicate that it is as much of a problem in men as it is in women while the level of unmet need in this group is high. Estimates of need for health care for this symptom should be multidimensional and assess both the severity of symptoms and the impact it has on quality of life.


Brain | 2010

Multi-system neurological disease is common in patients with OPA1 mutations

Patrick Yu-Wai-Man; Philip G. Griffiths; Grainne S. Gorman; Charles Marques Lourenço; A. F. Wright; Michaela Auer-Grumbach; Antonio Toscano; Olimpia Musumeci; Maria Lucia Valentino; Leonardo Caporali; Costanza Lamperti; Chantal Tallaksen; P. Duffey; James Miller; Roger G. Whittaker; Mark R. Baker; Margaret Jackson; Michael P. Clarke; Baljean Dhillon; Birgit Czermin; Joanna D. Stewart; Gavin Hudson; Pascal Reynier; Dominique Bonneau; Wilson Marques; Guy Lenaers; Robert McFarland; Robert W. Taylor; Douglass M. Turnbull; Marcela Votruba

Additional neurological features have recently been described in seven families transmitting pathogenic mutations in OPA1, the most common cause of autosomal dominant optic atrophy. However, the frequency of these syndromal ‘dominant optic atrophy plus’ variants and the extent of neurological involvement have not been established. In this large multi-centre study of 104 patients from 45 independent families, including 60 new cases, we show that extra-ocular neurological complications are common in OPA1 disease, and affect up to 20% of all mutational carriers. Bilateral sensorineural deafness beginning in late childhood and early adulthood was a prominent manifestation, followed by a combination of ataxia, myopathy, peripheral neuropathy and progressive external ophthalmoplegia from the third decade of life onwards. We also identified novel clinical presentations with spastic paraparesis mimicking hereditary spastic paraplegia, and a multiple sclerosis-like illness. In contrast to initial reports, multi-system neurological disease was associated with all mutational subtypes, although there was an increased risk with missense mutations [odds ratio = 3.06, 95% confidence interval = 1.44–6.49; P = 0.0027], and mutations located within the guanosine triphosphate-ase region (odds ratio = 2.29, 95% confidence interval = 1.08–4.82; P = 0.0271). Histochemical and molecular characterization of skeletal muscle biopsies revealed the presence of cytochrome c oxidase-deficient fibres and multiple mitochondrial DNA deletions in the majority of patients harbouring OPA1 mutations, even in those with isolated optic nerve involvement. However, the cytochrome c oxidase-deficient load was over four times higher in the dominant optic atrophy + group compared to the pure optic neuropathy group, implicating a causal role for these secondary mitochondrial DNA defects in disease pathophysiology. Individuals with dominant optic atrophy plus phenotypes also had significantly worse visual outcomes, and careful surveillance is therefore mandatory to optimize the detection and management of neurological disability in a group of patients who already have significant visual impairment.


American Journal of Human Genetics | 2005

Heterozygous mutations of OTX2 cause severe ocular malformations

Nicola Ragge; Alison Brown; Charlotte M. Poloschek; Birgit Lorenz; R. Alex Henderson; Michael P. Clarke; Isabelle Russell-Eggitt; Alistair R. Fielder; Dianne Gerrelli; Juan Pedro Martinez-Barbera; Piers Ruddle; Jane L. Hurst; J. Richard O. Collin; Alison Salt; Simon T. Cooper; Pamela J. Thompson; Sanjay M. Sisodiya; Kathleen A. Williamson; David Fitzpatrick; Veronica van Heyningen; Isabel M. Hanson

Major malformations of the human eye, including microphthalmia and anophthalmia, are examples of phenotypes that recur in families yet often show no clear Mendelian inheritance pattern. Defining loci by mapping is therefore rarely feasible. Using a candidate-gene approach, we have identified heterozygous coding-region changes in the homeobox gene OTX2 in eight families with ocular malformations. The expression pattern of OTX2 in human embryos is consistent with the eye phenotypes observed in the patients, which range from bilateral anophthalmia to retinal defects resembling Leber congenital amaurosis and pigmentary retinopathy. Magnetic resonance imaging scans revealed defects of the optic nerve, optic chiasm, and, in some cases, brain. In two families, the mutations appear to have occurred de novo in severely affected offspring, and, in two other families, the mutations have been inherited from a gonosomal mosaic parent. Data from these four families support a simple model in which OTX2 heterozygous loss-of-function mutations cause ocular malformations. Four additional families display complex inheritance patterns, suggesting that OTX2 mutations alone may not lead to consistent phenotypes. The high incidence of mosaicism and the reduced penetrance have implications for genetic counseling.


BMJ | 2003

Randomised controlled trial of treatment of unilateral visual impairment detected at preschool vision screening

Michael P. Clarke; Charlotte M. Wright; Susan Hrisos; J D Anderson; J Henderson; S Richardson

Abstract Objectives To test the efficacy of treatment for unilateral visual loss detected by preschool vision screening and the extent to which effectiveness varies with initial severity. Design Randomised controlled trial of full treatment with glasses and patching, if required, compared with glasses only or no treatment. Masked assessment of best corrected acuity after one year of follow up. Setting Eight UK eye departments. Participants 177 children aged 3-5 years with mild to moderate unilateral impairment of acuity (6/9 to 6/36) detected by screening. Results Children in the full and glasses treatment groups had incrementally better visual acuity at follow up than children who received no treatment, but the mean treatment effect between full and no treatment was equivalent to only one line on a Snellen chart (0.11 log units; 95% confidence interval 0.050 to 0.171; P < 0.0001). The effects of treatment depended on initial acuity: full treatment showed a substantial effect in the moderate acuity group (6/36 to 6/18 at recruitment) and no significant effect in the mild acuity group (6/9 to 6/12 at recruitment) (P = 0.006 for linear regression interaction term). For 64 children with moderate acuity loss the treatment effect was 0.20 log units, equivalent to one to two lines on a Snellen chart. When all children had received treatment, six months after the end of the trial, there was no significant difference in acuity between the groups. Conclusions Treatment is worth while in children with the poorest acuity, but in children with mild (6/9 to 6/12) unilateral acuity loss there was little benefit. Delay in treatment until the age of 5 did not seem to influence effectiveness.


Journal of Pediatric Ophthalmology & Strabismus | 1992

The Ocular Manifestations of the Sturge-Weber Syndrome

Timothy J. Sullivan; Michael P. Clarke; Jd Morin

Sturge-Weber syndrome (SWS) is a rare neuro-oculocutaneous disorder. The ocular component manifests as glaucoma and vascular malformations of the conjunctiva, episclera, choroid, and retina. The authors reviewed the records of and recalled for examination 51 consecutive patients with a diagnosis of SWS seen at The Hospital for Sick Children, Toronto, Ontario, Canada, from 1980 to 1991. Of the 51 patients, 36 (71%) had glaucoma, 26 experienced onset before 24 months of age and the remainder after 66 months of age, 35 (69%) had conjunctival or episcleral hemangiomas, and 28 (55%) had choroidal hemangiomas, which were bilateral in 12 patients. Other ocular manifestations (retinal vascular tortuosity, iris heterochromia, retinal detachment, and strabismus) also occurred. Thirty-four of 51 (67%) glaucomatous eyes had a final visual acuity of 20/40 or better, or central, steady, and maintained fixation in each eye.


Ophthalmology | 2010

The prevalence and natural history of dominant optic atrophy due to OPA1 mutations.

Patrick Yu-Wai-Man; Philip G. Griffiths; Ailbhe Burke; Sellar Pw; Michael P. Clarke; Lawrence Gnanaraj; Desiree Ah-Kine; Gavin Hudson; Birgit Czermin; Robert W. Taylor; Rita Horvath; Patrick F. Chinnery

PURPOSE Autosomal dominant optic atrophy (DOA) is a major cause of visual impairment in young adults that is characterized by selective retinal ganglion cell loss. To define the prevalence and natural history of this optic nerve disorder, we performed a population-based epidemiologic and molecular study of presumed DOA cases in the north of England. DESIGN Case series. PARTICIPANTS Seventy-six affected probands with a clinical diagnosis of DOA were identified from our neuro-ophthalmology and neurogenetics database. METHODS OPA1 genetic testing was performed using a polymerase chain reaction-based sequencing strategy. OPA1-negative cases were then screened for large-scale OPA1 rearrangements and OPA3 mutations. Additional affected family members identified through contact tracing were examined, and longitudinal visual data were analyzed. MAIN OUTCOME MEASURES The prevalence and molecular characteristics of DOA in the north of England. Visual function and disease progression among patients with OPA1-positive mutations. RESULTS The detection rate of OPA1 mutations was 57.6% among probands with a positive family history of optic atrophy (19/33) and 14.0% among singleton cases (6/43). Approximately two thirds of our families with DOA harbored OPA1 mutations (14/22, 63.6%), and 5 novel OPA1 mutations were identified. Only 1 family carried a large-scale OPA1 rearrangement, and no OPA3 mutations were found in our optic atrophy cohort. The minimum point prevalence of DOA in the north of England was 2.87 per 100,000 (95% confidence interval [CI], 2.54-3.20), or 2.09 per 100,000 (95% CI, 1.95-2.23) when only OPA1-positive cases were considered. Snellen visual acuity varied markedly between OPA1-positive cases with a mean of 20/173 (range 20/20 to hand movements), and visual function worsened in 67.4% of patients during follow-up. The mean rate of visual loss was 0.032 logarithm of the minimum angle of resolution per year, but some patients experienced faster visual decline (range = 0-0.171 logarithm of the minimum angle of resolution/year). OPA1 missense mutations were associated with a significantly worse visual outcome compared with other mutational subtypes (P=0.0001). CONCLUSIONS Dominant optic atrophy causes significant visual morbidity and affects at least 1 in 35,000 of the general population.


Movement Disorders | 2011

Visual symptoms in Parkinson's disease and Parkinson's disease dementia†‡§

Neil Archibald; Michael P. Clarke; Urs Peter Mosimann; David J. Burn

Visual symptoms are common in PD and PD dementia and include difficulty reading, double vision, illusions, feelings of presence and passage, and complex visual hallucinations. Despite the established prognostic implications of complex visual hallucinations, the interaction between cognitive decline, visual impairment, and other visual symptoms remains poorly understood. Our aim was to characterize the spectrum of visual symptomatology in PD and examine clinical predictors for their occurrence. Sixty‐four subjects with PD, 26 with PD dementia, and 32 age‐matched controls were assessed for visual symptoms, cognitive impairment, and ocular pathology. Complex visual hallucinations were common in PD (17%) and PD dementia (89%). Dementia subjects reported illusions (65%) and presence (62%) more frequently than PD or control subjects, but the frequency of passage hallucinations in PD and PD dementia groups was equivalent (48% versus 69%, respectively; P = 0.102). Visual acuity and contrast sensitivity was impaired in parkinsonian subjects, with disease severity and age emerging as the key predictors. Regression analysis identified a variety of factors independently predictive of complex visual hallucinations (e.g., dementia, visual acuity, and depression), illusions (e.g., excessive daytime somnolence and disease severity), and presence (e.g., rapid eye movement sleep behavior disorder and excessive daytime somnolence). Our results demonstrate that different “hallucinatory” experiences in PD do not necessarily share common disease predictors and may, therefore, be driven by different pathophysiological mechanisms. If confirmed, such a finding will have important implications for future studies of visual symptoms and cognitive decline in PD and PD dementia.


Parkinsonism & Related Disorders | 2011

Retinal thickness in Parkinson's disease

Neil Archibald; Michael P. Clarke; Urs Peter Mosimann; David J. Burn

BACKGROUND Visual symptoms are common in Parkinsons disease with studies consistently demonstrating reductions in visual acuity, contrast sensitivity, colour and motion perception as well as alterations in electroretinogram latencies and amplitudes. Optical coherence tomography can examine retinal structure non-invasively and retinal thinning has been suggested as a potential biomarker for neurodegeneration in Parkinsons disease. Our aim was to examine the retinal thickness of a cohort of Parkinsons disease subjects (and age-matched controls) to establish the practical utility of optical coherence tomography in a representative older Parkinsons disease group. METHODS Fifty-one established Parkinsons disease subjects and 25 healthy controls were subjected to ophthalmological assessment and optical coherence tomography (Zeiss Stratus 3000™) of macular thickness and volume and retinal nerve fibre thickness around the optic nerve head. Twenty four percent of control and 20% of Parkinsons disease subjects were excluded from final analysis due to co-morbid ocular pathology. Further data was excluded either due to poor tolerability of optical coherence tomography or poor quality scans. RESULTS Despite a reduction in both visual acuity and contrast sensitivity in the residual evaluable Parkinsons disease cohort, we did not detect any differences between the two study groups for any measures of retinal thickness, in contrast to previously published work. CONCLUSIONS In addition to technical problems inherent in the evaluation, the lack of difference between Parkinsons disease and healthy control subjects suggests longitudinal studies, employing newer techniques, will be required to define the role of optical coherence tomography as a potential diagnostic biomarker.


International Journal of Geriatric Psychiatry | 2008

A semi-structured interview to assess visual hallucinations in older people

Urs Peter Mosimann; Daniel Collerton; Robert Dudley; Thomas D. Meyer; Gemma Graham; Jennifer L. Dean; Daniel Bearn; Alison Killen; Lucy Dickinson; Michael P. Clarke; Ian G. McKeith

Visual hallucinations are under‐reported by patients and are often undiscovered by health professionals. There is no gold standard available to assess hallucinations. Our objective was to develop a reliable, valid, semi‐structured interview for identifying and assessing visual hallucinations in older people with eye disease and cognitive impairment.


British Journal of Ophthalmology | 2004

The Newcastle Control Score: a new method of grading the severity of intermittent distance exotropia

H Haggerty; S Richardson; Susan Hrisos; N P Strong; Michael P. Clarke

Aim: To describe the development and application of a novel scoring system for grading the severity of intermittent distance exotropia (IDEX) and its potential application as an intervention criterion for surgical intervention. Methods: The Newcastle Control Score (NCS) for IDEX was developed by incorporating both subjective (home control) and objective (clinic control) criteria into a scale to grade severity. The score structure described was evaluated for interobserver and test-retest reliability. To determine an optimal score threshold for surgical intervention, 170 cases of IDEX were scored retrospectively. Cure rates for surgical and non-surgical cases were then compared according to preoperative or presenting scores. Results: Interobserver and test-test reliability were good (r = 0.82 and r = 0.89 respectively). Total cure rate with surgery was 54% and without surgery 18% (χ2 = 23.093, df = 1, p<0.001). Significantly fewer patients with NCS ⩾3 achieved cure without surgery than those with NCS 2 (χ2 = 3.362, df = 1, p<0.047). Conclusions: The NCS is a reliable method for grading the severity of IDEX and aids decisions regarding intervention. Patients with a score of 3 or more are unlikely to attain a cure without surgery.

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Timothy J. Sullivan

Royal Brisbane and Women's Hospital

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N P Strong

Royal Victoria Infirmary

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H Haggerty

Royal Victoria Infirmary

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