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Progressive cochleovestibular impairment caused by a point mutation in the COCH gene at DFNA9.

OBJECTIVES: Analysis of phenotype-genotype correlation. STUDY DESIGN: Family study. METHODS: Auditory and vestibulo-ocular functions were examined in a Dutch family with autosomal dominantly inherited sensorineural hearing impairment caused by a 208C > T mutation in the COCH gene, located in chromosome 14q12-q13 (DFNA9). Linear regression analysis of individual longitudinal hearing threshold data (n = 11) on age was performed. RESULTS: Fifteen of the 16 genetically affected persons could be evaluated. They all developed hearing and vestibular impairment symptoms--and in many cases also cardiovascular disease--in the fourth to fifth decade. At the low frequencies (0.25-2 kHz), hearing loss started at the age of about 40 years and showed an average annual progression of approximately 3 dB, finally resulting in profound hearing losses. In two exceptional cases, annual progression attained levels of up to 24 dB. At the high frequencies (4-8 kHz), the average threshold increased from about 50 dB at the age of 35 years to about 120 dB at the age of 75 years (which amounts to 1.8 dB annual threshold increase). All affected individuals tested showed normal ocular motor functions. The patients older than 46 years generally showed absence of the vestibulo-ocular reflex, but their cervico-ocular reflex was enhanced compared with normal subjects, whereas those aged 40 to 46 years showed either severe vestibular hyporeflexia or unilateral caloric areflexia. CONCLUSION: These findings suggest a gradual development of cochleovestibular impairment caused by the new mutation found.

Adult↗

Statistical approaches in the development of clinical practice guidelines from expert panels: the case of laminectomy in sciatica patients.

BACKGROUND: Variation in expert opinion and lack of a systematic methodology hinder the development of reliable clinical practice guidelines. However standardized protocols have been defined to quantify, combine, and summarize expert judgments. In addition, statistical methods may help to outline guidelines based on simplified models of these judgments. METHODS: To test this hypothesis, stepwise logistic regression (SLR) and classification tree pruning (CTP) were used to predict the results of two expert panels (USA 1992 and Switzerland 1995) on laminectomy in sciatica conditions. Both panels, using the RAND-UCLA explicit method, assessed whether the procedure would be inappropriate or of potential use in 720 case scenarios combining 7 relevant factors. RESULTS: Laminectomy was rated as inappropriate in 60% and 70% of the scenarios by the US and Swiss panels, respectively. Either statistical method, in both panels, based its simplest model on the same 4 factors, as follows: imaging test results; disability; neurological findings; and conservative treatment trials (in decreasing order); the influence of 2 other factors, duration of pain and nerve root irritation, were only marginal. The correct classification rates of the models were 89% and 93% for SLR and 93% and 85% for CTP. Adopting the CTP US algorithm as a guideline would lead to consider performing laminectomy only in patients with imaging evidence of hernia, relatively severe disability, reflex abnormalities, and previous nonsurgical treatment. Adherence to the corresponding CTP Swiss algorithm would result in less restrictive conditions. CONCLUSION: The statistical techniques proved as useful instruments to structure and simplify appropriateness criteria developed by expert panels and to outline parsimonious decision models for clinical practice.

Algorithms↗

Paralysis of accommodation in infectious mononucleosis.

A case report of a 22-year-old patient with accommodative paralysis is presented including (1) the five-year history beginning with infectious mononucleosis; (2) recent clinical examination showing accomodative paralysis and reduced pupilary responses to light and near; (3) objective recordings confirming both the absence of any accommodation and the presence of pupillary responses to monocular and binocular near stimuli and to light, the latter with pupillary escape; and finally (4) neuropharmacological tests showing 7-diopter accommodative responses to pilocarpine (an acetylcholine substitute acting directly on the ciliary muscle receptor sites) and absent responses to demecarium bromide (a cholinesterase blocking agent which potentiates neurally released acetylcholine). Infectious mononucleosis includes ocular signs and symptoms. In young persons with accommodative difficulties, infectious mononucleosis should be suspected.

Accommodation, Ocular↗

Diagnosis of diseases of the lumbar spine: correlation of computerized tomography with myelography and clinical findings.

Data from 339 patients referred for evaluation of suspected lumbar disease were studied retrospectively to correlate findings in the routine clinical evaluation with results of computed tomography and myelography. Clinical features from the patients' history that correlated with an abnormal CT and myelogram included age greater than or equal to 40, a history of previous surgery, and absence of a history of injury. Signs from the physical examination that correlated included reduced lumbar motion, a motor or sensory deficit, abnormal reflexes, and reduced capacity for straight leg-raising or walking. Using a clinical score incorporating these variables, we suggest a diagnostic strategy to promote more efficient and selective use of CT scans and myelograms. We project that the use of this diagnostic approach can reduce the number of myelograms ordered in a similar population by more than 50%.

Adult↗

Evaluation of blink reflex results obtained from workers previously diagnosed with solvent-induced toxic encephalopathy.

We reviewed blink reflexes recorded from 51 railroad workers with long-term occupational exposure to solvents who were diagnosed by others with solvent-induced toxic encephalopathy. No worker fulfilled conventional clinical criteria for dementia or trigeminal mononeuropathy. All workers had normal R1 and R2 blink reflex latencies. R1 latencies correlated significantly with several nerve conduction measures, including F wave latencies, suggesting that some intersubject variability reflected intrinsic conduction properties, not isolated brain-stem function. Although normal, the workers' R1 latencies were significantly prolonged compared with historical control groups, including gender-matched control subjects of similar mean age (11.2 ms vs 9.9 ms; P < 0.0001). Stepwise multiple regression models demonstrated significant associations of R1 latency with age and use of CNS-active prescription medications (P = 0.003), but duration of occupational solvent exposure did not enter into the models. Paradoxically, workers using CNS-active medications had significantly shorter R1 latencies compared with workers not using such medications (10.9 vs 11.7 ms; P = 0.01). Job title, another potential surrogate measure of exposure, was not significantly related to reflex latencies. The geographical site of predominant solvent exposure did influence R1 latency, and workers from one site had longer exposure duration and longer R1 latencies than remaining workers. However, an interaction between age and exposure duration (r = 0.39; P = 0.003) confounded interpretation of this observation. Disability or work status, mental status findings, or classification of encephalopathy did not influence blink reflex latencies. The overall results do not support, but do not entirely exclude, a possible relationship between subclinical blink reflex abnormalities and occupational exposure to solvents. Nevertheless, it is clear from these results that the small group differences in R1 latency between exposed workers and control subjects are of no diagnostic importance and of uncertain physiologic importance, and they may reflect unrecognized confounders and technical factors.

Adult↗

Idiopathic unilateral hyperhidrosis with Holmes-Adie syndrome: case report.

Hyperhidrosis is a disease that is characterized by excessive sweating due to hyperactivation of eccrine sweat glands. It may be localized or generalized form. Holmes-Adie syndrome is an idiopathic disease with unilateral pupil dilatation and loss of deep tendon reflexes. We present a 37-year-old female patient diagnosed with unilateral hyperhidrosis coincident with Holmes-Adie syndrome because of this unusual presentation.

Adie Syndrome↗

Hyperexplexia: an inherited disorder of the startle response.

A family is presented with hyperexplexia, a rare autosomal dominant neurological disorder. Affected individuals manifest flexor hypertonia and hypokinesia during infancy. Later and throughout life, the condition is characterized by exaggerated involuntary myoclonic startle reactions, which on occasion result in falling. There are also marked nocturnal myoclonic jerks. Many family members have had congenital hip dislocations and inguinal hernias. Pre- and postnatal hypertonia is proposed as the cause for these problems. The nature and location of central nervous system dysfunction in hyperexplexia was investigated using electroencephalographic and brainstem-evoked response techniques. A dysfunction of cortical inhibition of the brainstem-mediated startle response is discussed as a possible pathogenic mechanism. Accurate diagnosis of this disorder is important in order to provide appropriate counseling and to initiate effective treatment.

Adolescent↗

Abnormal gastro-oesophageal reflux in Chinese with atypical chest pain.

Although atypical chest pain has been well described in the Western population, its frequency in Chinese is unknown. Over a period of 42 months, we studied 521 Chinese patients with chest pain and identified 108 patients (20.7%) whose pain was not related to cardiac causes, as determined by exercise ECG or cardiac catheterization. Using 24 h ambulatory pH monitoring and baseline oesophageal manometry, 28.7, 19.4 and 5.6% of these patients were found to have abnormal reflux parameters, abnormal manometric findings or both, respectively. There were significantly more patients complaining of chest pain during the study in the gastro-oesophageal reflux disease (GERD) group than in the non-GERD group (16/31 vs 20/77; P < 0.001). The lower oesophageal sphincter pressure was lower in those with abnormal reflex parameters than in those with normal reflux parameters (12.7 +/- 5.4 vs 17.8 +/- 5.8 mmHg; P < 0.05). There was no significant difference in symptoms, such as heartburn (54.8 vs 42.9%), regurgitation (38.7 vs 35.1%) and dysphagia (19.4 vs 24.7%), among the two groups. Non-specific changes were the most frequent baseline motility pattern. In conclusion, atypical chest pain and gastro-oesophageal reflux disease are not uncommon in Chinese and this deserves special emphasis as the continuation of anti-anginal drugs may aggravate their condition.

Adolescent↗

Cross-cultural comparison of the neurobehavioral characteristics of Chinese and Japanese neonates.

BACKGROUND: Similarities and differences in the neurobehavioral repertoire of neonates from different cultures have been noted using the Brazelton Neonatal Behavioral Assessment Scale (NBAS). By identifying the behavioral attributes of newborns that are seen more universally versus those that are culture-specific, comparative studies increase understanding of the roles of cultural factors in shaping the behavioral trajectory of infants. This study compared the neurobehavioral characteristics of neonates in Chengdu, China and Nagasaki, Japan. METHODS: The Brazelton NBAS was administered within the first week of life to 40 Chinese and 62 Japanese healthy, full-term neonates in Chengdu and Nagasaki. RESULTS: The two groups differed significantly in birthweight, gender, age at time of exam, mode of delivery, and gestational age. When these variables, in addition to group status (Chinese or Japanese), were entered into multiple linear analyses with NBAS cluster scores as dependent variables, group status independently predicted Range of State and Habituation scores. The group status did not predict Orientation, Motor, Regulation of States, Autonomic Stability, and Abnormal Reflexes cluster scores. CONCLUSION: These results suggest that Japanese newborns habituated more readily to stimuli, and were less irritable than newborns in the Chinese sample. The infants in the two groups shared many similar neurobehavioral characteristics as well. The implications of these similarities and differences were discussed.

China↗

Discrimination between painful and painless diabetic neuropathy based on testing of large somatic nerve and sympathetic nerve function.

The syndromes of painful diabetic neuropathy and painless foot ulceration are distinct clinical entities. To investigate whether there is a pattern of nerve fibre involvement that could clearly discriminate between them, we have studied three groups of diabetic patients, 19 with painful neuropathy, 14 with painless foot ulceration, and 19 with no clinical neuropathy. Large somatic nerve fibre function was assessed by nerve conduction studies and vibration thresholds, small somatic nerve function by cooling and warming thresholds, the parasympathetic system by heart-rate dependent cardiac autonomic reflexes, and the sympathetic system by postural drop in blood pressure and plasma noradrenaline (supine and erect). Normal ranges were obtained from 25 age-matched healthy subjects. Painful neuropathy was characterized by uniform dysfunction of small somatic fibres and preserved sympathetic nerve activity (plasma noradrenaline) with a wide range of large somatic fibre and autonomic reflex abnormalities. By contrast, in painless foot ulceration there was universal severe dysfunction of all nerve fibre populations. Discriminant analysis identified peroneal motor conduction velocity as the best single variable for distinguishing between painful and painless neuropathy (81% of cases). A combination of peroneal motor conduction velocity with vibration threshold and plasma noradrenaline discriminated completely between the two clinical syndromes. These findings suggest that the key differences between painful and painless diabetic neuropathy are in large somatic and sympathetic fibre function.

Diabetic Neuropathies↗

Quantitative measurement of spasticity in children with cerebral palsy.

Spasticity was quantified in nine children with spastic diplegia, using a sinusoidal displacement of the foot at frequencies from 3 to 12Hz. Ankle-joint stiffness was separated into elastic (energy-storing) and viscous (energy-dissipating) components. 'Path length' was used to represent the variation in stiffness over this frequency range. Compared with 11 unaffected children, a significant difference in path lengths was demonstrated for the children with spasticity. An age-dependent effect was demonstrated when path lengths of unaffected children were compared with those of 10 unaffected adults. A modified path-length measure is proposed which minimizes age dependency, yet enables detection of spasticity. Passive stiffness properties of unaffected adults showed higher elastic stiffness, viscosity and friction than unaffected children. A method was developed to evade the need for temporary nerve blocks to calculate inerital properties of the foot in persons with spasticity.

Biomechanical Phenomena↗

Neural monitoring of vasovagal syncope.

Head-up tilt testing has become a valuable and widely accepted diagnostic tool for evaluation of patients with vasovagal syncope. This test has afforded clinical researchers the opportunity to focus on the hemodynamic, humoral, and neural changes that accompany syncope. We review the animal and clinical studies that provide insight into the possible pathophysiological mechanisms involved in vasovagal syncope. Hemodynamic measurements in patients with vasovagal syncope suggest that a relative decrease in ventricular size and increase in cardiac contractility may be seen in many patients with vasovagal syncope. Patients with vasovagal syncope have also demonstrated numerous "exaggerated" neurohumoral responses to syncope. Differential changes in plasma levels of epinephrine, renin, endothelin, vasopressin, cortisol, prolactin, beta endorphins, and substance P have been reported by some investigators either prior to or during a syncopal episode in patients with vasovagal syncope. The precise pathophysiological significance of these measurements is unknown at the present time. Measurements of autonomic tone may be accomplished indirectly with analysis of heart rate variability or baroreflex slope, or directly by sympathetic neural recordings of the peroneal nerve. We have demonstrated decreased baroreflex slopes in patients with vasovagal syncope. Using microneurography, we and others have demonstrated decreased sympathetic nerve activity occurring 11 +/- 3 seconds prior to syncope during head-up tilt table testing. A variety of other abnormal reflexes, including blunted forearm blood flow responses during exercise, have been demonstrated by others. These observations suggest that pacing instituted after the event may not be as helpful as the use of a hemodynamic sensor that will result in the initiation of pacing prior to sympathetic withdrawal or modify the decrease in sympathetic tone that occurs prior to syncope.

Adrenergic Agonists↗