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Biomedical subjects

C M Wiles

Publications and source records attributed to C M Wiles.

At least 55 records · Page 3Linked to original sources
PubMed1996

Simultaneous electrical impedance tomography and videofluoroscopy in the assessment of swallowing.

Simultaneous videofluoroscopy and electrical impedance tomography (EIT) were performed in 13 patients. Subjects swallowed a low-conductivity and a higher-conductivity bolus of between 5 and 20 ml. EIT images from the two swallows were then subtracted to cancel out movement related changes. The peak in the conductivity change was most closely associated in time with a point at which the pharynx is filled with bolus: this suggests that the subtraction process does produce data and images which are related to the bolus rather than to movement of involved structures. The full width at 50% and 75% of the maximum of the time conductivity plot was correlated with the time taken for the bolus to be cleared from the mouth (r = 0.63 and 0.68 respectively, p < 0.05 for both). Despite the sampling frequency of only 9 frames s-1, compared to 50 frames s-1 for videofluoroscopy, EIT recordings from the neck are able to detect the presence of a conductive bolus in the pharynx and for the first time the relationship between parameters of an EIT time-conductivity plot and a measure of bolus transit using an accepted technique has been established.

Adult↗
PubMed1996

Clinical measurement of swallowing in health and in neurogenic dysphagia.

We studied clinical features potentially related to dysphagia and three indices from a timed test of swallowing--average volume per swallow (ml), average time (s) per swallow and swallowing capacity (ml/s)--in 181 screened healthy adults and 30 patients with motor neurone disease (MND). In healthy adults, age, sex and height accounted for 44.3% and 55.6% of the variance of log average volume per swallow and log swallowing capacity, respectively. Symptoms and signs were more prevalent in the MND group and were associated with reduced swallowing capacity and reduced average volume per swallow; repeatability studies on these two indices in both groups showed that the median difference between the mean of two recordings on successive days and the mean of all recordings (6-15 over 3 days) was < 5% (maximum third quartile 12.8%, indices expressed as percent predicted according to age and sex). Using this simple bedside test, swallowing function can be quantified on a ratio scale and expressed as percent of that predicted by age and sex; such information may improve the predictive value of clinical assessment and provides a practical way of monitoring change in patients with dysphagia.

Adolescent↗
PubMed1996

Respiratory insufficiency in neuronopathic and neuropathic disorders.

Twenty-nine patients with a neuronopathic or neuropathic disorder were referred for assessment of respiratory insufficiency between 1978 and 1994. Diagnoses included spinal muscular atrophy (6), chronic idiopathic demyelinating neuropathy (4), Vialetto-van Laere syndrome (3), hereditary motor and sensory neuropathy (3) and a miscellaneous group (5). We also describe seven patients with Guillain-Barré syndrome (GBS) who required long-term ventilatory support for over 6 months to 7 years after the initial illness. Respiratory insufficiency occurred as a consequence of respiratory muscle weakness, impaired bulbar function and restrictive lung defects. In some groups presentation was with progressive nocturnal hypoventilation culminating in acute respiratory failure. Five patients with GBS or chronic idiopathic demyelinating neuropathy were weaned from ventilatory support up to 18 months after the initial illness. The remaining 24 patients required continuous or nocturnal ventilatory support using intermittent positive-pressure ventilation (13), negative pressure ventilation (4), nasal-mask-delivered intermittent positive-pressure ventilation (4), nasal-mask-delivered continuous positive-pressure ventilation (3), mouthpiece-assisted ventilation by day (2) and rocking bed (1). None have been weaned from support after a period of ventilation ranging from one month to 10 years. Eight patients have subsequently died.

Adolescent↗
PubMed1996

Measurement of swallowing in patients with sore throats.

Swallowing function was measured using a simple timed test in 20 healthy subjects with a sore throat (16 women, median age [range] 27.5 years [19.3-44.5]) and the test was repeated following recovery. All three indices from the test average volume per swallow (ml), average time per swallow (s) and swallowing capacity (mls-1) were significantly improved following recovery (P = 0.0001, 0.041 and 0.0001 respectively). There was no significant change in respiratory function between the two visits. The indices from a timed test of swallowing are sensitive enough to detect changes occurring due to a sore throat; the test provides a simple bedside technique for quantifying swallowing and may be useful in measuring the rate of recovery from swallowing problems and in assessing the effect of different treatments on swallowing function.

Adult↗
PubMed1996

Palatal and pharyngeal reflexes in health and in motor neuron disease.

Palatal and pharyngeal sensation and motor responses, and volitional palatal movement, were tested in 171 healthy adults and 43 patients with motor neuron disease. In healthy adults palatal and pharyngeal sensation and volitional palatal elevation were present in all; the palatal and pharyngeal motor responses could not be elicited on first testing in two (1.1%) and seven (4.1%) subjects respectively. Pharyngeal motor responses were more easily elicited in older subjects and palatal responses were more easily elicited in women. Eye watering and retching were the most common accompanying features. In 57 normal subjects tested on five occasions there was considerable variation in the stimulus required to elicit the motor responses within subjects: in none of four subjects (7%) who initially had absent responses were they always absent. Pharyngeal motor responses were more easily elicited in patients with motor neuron disease than in matched normal subjects; within the motor neuron disease group pharyngeal motor responses elicited by tongue depression were associated with the symptom of food or drink "going down the wrong way" > 1/month and a reduction in average volume per swallow (ml) and swallowing capacity (ml/s). Volitional palatal elevation was absent in five patients (11.6%). In six of eight patients with motor neuron disease studied repeatedly (on between two and seven occasions) the palatal and pharyngeal responses were elicited with the same stimulus on each occasion. In healthy adults palatal and pharyngeal sensation and motor responses should be present although considerable variation occurs in the stimulus required. In patients with motor neuron disease features of impaired swallowing are associated with a brisk rather than a depressed pharyngeal response.

Adolescent↗
PubMed1995

The repeatability and variability of electrical impedance tomography indices of pharyngeal transit time in normal adults.

Two electrical impedance tomography (EIT) indices of pharyngeal transit time have been repeatedly measured in 20 normal adults. The time course of change in pharyngeal conductivity whilst swallowing 5, 10 and 20 ml boluses was expressed either as a full width at 20% maximum (FW20) or as a full width at 50% maximum (FW50): the latter could be satisfactorily measured more frequently. Mean coefficients of variation for FW20 and FW50 tended to decrease with increasing bolus volume but this was statistically significant only for FW50 in men. FW20 and FW50 were significantly shorter in men than women and increased with increasing age. FW50 was significantly smaller when larger bolus volumes were swallowed. FW50 was significantly shorter when low-conductivity fluid was used and there was an insignificant trend for it to be longer with electrodes in the highest position. The amplitude of the conductivity change recorded was significantly affected by all factors studied apart from age. If EIT is to be used as a technique for monitoring changes in pharyngeal transit time in patients with neurogenic dysphagia, repeat examinations should be performed under the same conditions and, if possible, large bolus volumes should be used.

Adult↗
PubMed1995

Risk estimates for developing motor neurone disease in first-degree relatives.

Patients with motor neurone disease resident in the three counties of South Glamorgan, Mid Glamorgan and Gwent (total population 1,394,400) from 1/11/91 to 31/12/92, were ascertained through general practitioners and neurology department records: 62 out of 71 (51 male, 20 female) index cases ascertained agreed to be visited. These individuals were clinically reviewed, had a detailed family history taken and, after discussion, had a blood sample taken for testing for the X-linked bulbospinal muscular atrophy mutation. The period prevalence of motor neurone disease was 5.02/100,000 with a mean age of onset of 59.4 (S.D. 12.9) years. One 66-year-old male was found to have the X-linked bulbospinal muscular atrophy mutation. A single, definite first-degree relative pair was identified, of whom only one was included in the data. The index cases had a total of 131 offspring and 173 siblings. The risk estimates, by current age, for these first-degree relatives of patients with apparently sporadic motor neurone disease decreased from 1 in 85 at age 20 years to 1 in 1683 at age 80 years. These estimates require confirmation in an independent sample, as they are based on a single "event".

Aged↗
PubMed1995

Progressive neuronal degeneration of childhood with liver disease (Alpers' disease) presenting in young adults.

Two unrelated and previously healthy girls, aged 17 and 18, presented with a subacute encephalopathy, visual and sensory symptoms and signs, and prominent seizures that were difficult to control. Brain MRI showed lesions (high signal on T2 weighted images) in the occipital lobes and thalamus; EEG showed slow wave activity with superimposed polyspikes. Inexorable downhill progression led to death in hepatic failure within eight months of onset. Histopathological findings in both patients ((a) chronic hepatitis with prominent bile duct proliferation, fatty change, and fibrosis; (b) in the brain a patchy destruction of the cerebral cortex, predominantly involving striate cortex) were characteristic of progressive neuronal degeneration of childhood with liver disease--Alpers-Huttenlocher syndrome--a rare autosomal recessive disorder usually seen in infants and young children.

Adolescent↗
PubMed1995

Correlations between changes in disability and T2-weighted brain MRI activity in multiple sclerosis: a follow-up study.

We obtained two conventional unenhanced T2-weighted brain MRI scans, separated by an interval of 24 to 36 months, in 281 patients with multiple sclerosis (MS). At the time of each scan, clinical disability was rated using the Kurtzke Expanded Disability Status Scale (EDSS). Changes in disability between the two examinations correlated weakly but significantly with the number of new (Spearman's rank correlation coefficient = 0.13; p = 0.02) and enlarging (Spearman's rank correlation coefficient = 0.18; p = 0.002) MRI lesions. This result suggests that brain T2-weighted MRI is a useful supplementary marker of disease activity in definitive (phase III) clinical treatment trials in MS.

Adult↗
PubMed1995

Management of mitochondrial disease on an intensive care unit.

Patients with mitochondrial disease may present to the Intensive Care Unit (ICU) with a variety of neurological and general medical disorders. Eleven patients were admitted to a neurological ICU between 1970 and 1992 because of respiratory insufficiency, status epilepticus and/or metabolic encephalopathy associated with mitochondrial disease. Respiratory impairment occurred in eight patients and was associated with nocturnal hypoventilation due to respiratory muscle weakness, aspiration due to bulbar weakness and abnormalities of central control leading to a reduced CO2 drive, irregular respiratory patterns and sleep apnoea. Seven patients received continuous respiratory support during the acute illness; three were subsequently weaned to domiciliary ventilation, and four died. Five patients had stroke-like episodes, which in two were recurrent. Four patients developed tonic-clonic grand mal epilepsy associated with myoclonic fits (2 patients), absences (2), focal fits (1) and status epilepticus (2). Encephalopathy was associated with recurrent lactic acidosis (2 patients), cardiac failure (2), hyponatraemia (2), renal abnormalities (3) and complete heart block (1). Although rare, mitochondrial disease should be considered in any patient with unexplained respiratory failure, intractable epilepsy, lactic acidosis or recurrent stroke.

Acidosis, Lactic↗
PubMed1995

Management and outcome of severe Guillain-Barré syndrome.

Seventy-nine patients with Guillain-Barré syndrome admitted to a neurological intensive therapy unit (ITU) between 1985 and 1992 were studied retrospectively. The mean age was 49.8 years (range 16-86) and the time between the first neurological symptom and admission to ITU was 10.2 days (0-62). Admission was precipitated by a combination of respiratory failure requiring ventilatory support (73.4%), bulbar weakness (57.0%), autonomic features (11.4%) and general medical factors (10.1%). Specific treatments included plasma exchange (65.8%), intravenous immunoglobulin (13.9%) and methylprednisolone/placebo (12.7%). Significant complications included lower respiratory tract infections (45.6%), hyponatraemia (25.3%), dysautonomia (19.0%), urinary tract infection (12.7%) and cognitive disturbances (8.9%). Four patients (5.1%) died during the acute illness. Duration of nadir correlated with duration of ventilation, duration of ITU stay and outcomes at 3 months, 6 months and 1 year. However, time to nadir, an indicator of rapidity of deterioration, did not correlate with any outcome. The low mortality in this series of acutely ill and severely disabled patients suggests that specialized intensive therapy units continue to have an important role in the management of acutely ill patients with Guillain-Barré syndrome.

Acute Disease↗
PubMed1995

Critical illness poly-neuropathy following severe hyperpyrexia.

Two patients developed critical illness polyneuropathy after severe hyperpyrexia. Fever was secondary to a phaeochromocytoma in one patient and sepsis in the other. These observations suggest that high fever may be one possible aetiology of critical illness polyneuropathy.

Adrenal Gland Neoplasms↗
PubMed1994

Swallowing in neurological outpatients: use of a timed test.

Swallowing was studied prospectively in a consecutive group of 90 neurology outpatients under 70 years of age. No patient had been referred primarily because of dysphagia. Patients were classified into four groups: those with (1) neurological or (2) non-neurological diagnoses possibly relevant to disordered swallowing, (3) functional disorders, and (4) definite diagnoses not likely to be relevant. They were defined as having abnormal or probably abnormal swallowing if two or more of the following were present: a complaint of swallowing problem, abnormal symptoms or signs, a slow swallowing speed (< 10 ml.s-1). Nineteen patients among the four groups (21%) were found to have abnormal/probably abnormal swallowing. Swallowing speed was significantly slower in patients who perceived a swallowing problem or who had abnormal symptoms or signs compared with those who did not, providing further evidence for the validity of a timed test of swallowing capacity. The study also provides evidence of a significant incidence of disordered swallowing in outpatients who may not have complained spontaneously but who have diagnoses potentially relevant to swallowing.

Adult↗
PubMed1994

An analysis of studies comparing electrical impedance tomography with x-ray videofluoroscopy in the assessment of swallowing.

Electrical impedance tomography can be used to record the conductivity change occurring in the neck during a swallow. X-ray videofluoroscopy provides excellent anatomical detail of the structures involved in swallowing and of the position of the swallowed bolus. The two techniques have been performed simultaneously on seven patients with swallowing problems to establish what produces the peak change in conductivity when a solution of low conductivity is swallowed. The results suggest that the exclusion of air from the larynx and pharynx is the major factor influencing the change in conductivity when a solution of low conductivity is swallowed.

Deglutition↗