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Biomedical subjects

J C Stevens

Publications and source records attributed to J C Stevens.

At least 91 records · Page 5Linked to original sources
PubMed1990

Trigeminal sensory neuropathy associated with connective tissue diseases.

We reviewed the clinical and laboratory features of 81 patients who had trigeminal sensory neuropathy (TSN) and a connective tissue disease (CTD). The neuropathy developed before the symptoms of CTD in 6/81 patients (7%), and in 38/81 patients (47%) TSN and CTD were diagnosed concurrently. The most frequently associated CTDs were undifferentiated connective tissue disease (38/81, 47%), mixed connective tissue disease (21/81, 26%), and scleroderma (15/81, 19%). Of 66 patients followed for more than 1 year (median, 5 years; range, 1 to 26 years), 8/66 patients (12%) had mild improvement and 2/66 (3%) had marked improvement of numbness; no patient had complete return of sensation. The facial numbness was frequently associated with moderate to severe facial pain that was usually resistant to pharmacologic therapy. None of the patients developed clinical or laboratory evidence of systemic vasculitis. The etiology of this cranial sensory neuropathy remains obscure.

Adult↗
PubMed1990

Missing ingredients: aging and the discrimination of flavor.

An experiment explored how well young, middle-aged, and elderly subjects could discriminate the presence or absence of the spice marjoram in a soup prepared according to a published recipe. Whereas most young made the discrimination at a level above chance, most middle-aged and elderly failed to. A clinical test that entails odor threshold and identification revealed that olfactory ability also diminished with age among these subjects. Furthermore, the odor thresholds measured in the test correlated significantly with the subjects' ability to discriminate flavor. Subsequent testing wherein subjects sought to discriminate flavor with their noses blocked confirmed that olfactory ability largely underlay the discrimination. The results emphasize that losses in olfaction measured most commonly with environmental odors are serious enough to have an impact on discrimination of flavors in everyday foods, even among persons of middle age. Loss of such discriminative capacity may entail risks of avoiding dangerous and overlooking beneficial ingredients in foods.

Adult↗
PubMed1990

The effect of stimulus level on click evoked oto-acoustic emissions and brainstem responses in neonates under intensive care.

Click evoked oto-acoustic emissions (EOAE) at a range of stimulus levels and the auditory brainstem response (ABR) threshold have been measured in 40 infants admitted to a neonatal intensive care unit (NICU). The stimulus levels at which the emissions were first observed had a similar mean value and distribution to those found in previous studies on normal newborns and young adult volunteers. The difference was in the proportion who had no detectable emissions, 16.7% as against 3.9% in the normal newborns and 2.6% in young adult volunteers. The distribution of thresholds for the ABR was again similar to those measured on normal newborns but 8.1% of the ears of the NICU infants had a threshold worse than 53 dBnHL compared with 0% for the normal newborns. A combined screening method starting with the click evoked oto-acoustic emission is proposed. A comparison of the mean ABR thresholds for those in whom an EOAE was recorded to those with no EOAE showed a group effect. The stimulus latency relationship of the NV peak showed too much variation between individual results to consider its use to define accurately the degree of conductive hearing loss.

Acoustic Stimulation↗
PubMed1990

Perceived roughness as a function of body locus.

Twenty subjects made magnitude estimates of the roughness of grooved metallic surfaces applied to 10 body loci. To a first approximation, perceived roughness grew as a power function of groove width, in accordance with earlier studies. The exponents and intercepts (up-down position in log-log coordinates) of the power function turn out to depend strongly on body locus. The straight lines in log-log coordinates tend to diverge with groove width so that differences among body loci are especially pronounced at large groove widths. Sensitivity to roughness was greatest for the lips, fingers, and forearm, and least for the heel, back, and thigh. The rank order of the body loci in terms of roughness sensitivity closely parallels the rank order for punctate pressure sensitivity, as reported by von Frey in 1894, but apparently not for other measures of tactile sensitivity, such as vibration thresholds to various frequencies, two-point thresholds, and error of point localization.

Adolescent↗
PubMed1989

Brain-stem auditory evoked potential abnormalities with unilateral brain-stem lesions demonstrated by magnetic resonance imaging.

We correlated the brain-stem auditory evoked potential (BAEP) abnormalities in 24 patients with discrete unilateral brain-stem lesions demonstrated by magnetic resonance imaging. In 18 patients who had BAEP abnormalities either confined to or more severe on stimulation of one ear, the lesion on magnetic resonance imaging was in the brain stem ipsilateral to the corresponding ear. Mesencephalic lesions produced amplitude abnormalities of the IV/V complex while pontine lesions resulted in abnormalities of earlier components (wave II and/or III). Prolongation of the I-III interpeak latency tended to occur with pontine lesions and of the III-V interpeak latency with mesencephalic lesions. Unilateral brain-stem lesions, particularly at the mesencephalic level, often produced BAEP abnormalities on both ipsilateral and contralateral monaural stimulation.

Adult↗
PubMed1989

Olfactory adaptation and recovery in old age.

Four experiments are reported in which it is shown that elderly adults are more prone than young adults to olfactory adaptation and are slower to recover threshold sensitivity. The first three experiments differed in detail, but had in common an initial threshold determination for 1-butanol, a 30 s exposure to a concentration twenty-seven times threshold, followed by repeated presentation of the initial threshold level at various intervals after adaptation. In three experiments accuracy of forced-choice discrimination was poor immediately after adaptation but tended to improve with time, and considerably faster in the young than in the elderly. In the fourth experiment, groups of twenty-three elderly and twenty-five young subjects threshold-matched for pyridine were compared. The subjects participated in three sessions in which pyridine was infused into a test chamber at either 2.5, 1.25, or 0 L min-1 (sham session). At 2.5 L min-1 both groups were able to track the buildup of odor intensity during infusion and its decline after infusion. In contrast, at 1.25 L min-1 only the young were able to track odor intensity, even though the concentration rose above initial threshold levels.

1-Butanol↗
PubMed1989

Inclusion body myositis. Observations in 40 patients.

Inclusion body myositis (IBM) was suspected on light microscopic grounds in 48 of 170 consecutive patients with inflammatory myopathies. One or more vacuoles containing membranous material, groups of atrophic fibres, and an autoaggressive endomysial inflammatory exudate occurred in 100, 96 and 92% of the muscle specimens. All three of these features were present in 88% of the specimens. Electron microscopy confirmed the presence of filamentous inclusions in 40 of 43 patients. The inclusions are typically near vacuoles and a minimum of three vacuolated fibres must be scrutinized to detect them with confidence. There is no electromyographic pattern that can reliably distinguish IBM from other inflammatory myopathies. The typical clinical features in the patients diagnosed by histological criteria as IBM were: insidious onset after age 50 yrs with painless, proximal lower extremity weakness; slow but relentless progression with selectively severe involvement of quadriceps, iliopsoas, tibialis anterior, biceps and triceps muscles; relatively early depression of the knee reflexes; and a normal or mildly elevated serum creatine kinase level. The male: female ratio was 3:1. Distal weakness occurred in about 50%, but only in 35% was it as great or greater than proximal weakness. Significant associated illnesses include other autoimmune disorders (15%), diabetes mellitus (20%), and diffuse peripheral neuropathy (18%). Prednisone treatment at dose levels frequently effective in polymyositis failed to prevent disease progression in those patients observed for 2 or more years. Our findings support the notion that IBM is a distinct entity in which a set of pathological features is associated with a constellation of clinical findings.

Adult↗
PubMed1989

Uniformity of olfactory loss in aging.

Most studies of how human olfaction changes with age have compared young and old. Essentially all such studies imply that aging takes a toll. The elderly have higher thresholds, perceive suprathreshold odors as being weaker, discriminate quality less well, recognize and identify common odors less well, and remember episodic presentations of odors poorly. To a first approximation, it appears that all odor qualities and functions undergo a general blunting. The few studies of persons between the young and the elderly suggest that the process of deterioration sets in early and progresses gradually. Such gradual deterioration would presumably allow the easiest accommodation to any loss and may account for why many elderly people seem oblivious to it. In some respects, ignorance may be bliss. For example, the diminished flavor of food may go unnoticed. In other respects, the loss of olfactory information may pose some nutritional and safety risks of which the elderly and perhaps even the middle-aged should be apprised. Longitudinal studies would seem to offer the only chance to decide the rate and magnitude of individual losses in olfaction. Such studies might also offer enlightenment regarding ways to forestall loss.

Adult↗
PubMed1989

Food quality reports from noninstitutionalized aged.

Over several years, we have compared olfaction in elderly subjects with that in young subjects. The main tests have been 1) absolute threshold, 2) magnitude matching to assess whether aging impairs suprathreshold odor and trigeminal strength, and 3) odor identification. As have other laboratories, we have found impairment by all three measures. In one study, we devised a composite score of olfactory competence based on all three measures; the outcome suggests that it is uncommon for a person over 70 years to escape a degree of impairment, although the degree varies from person to person. We speak here of persons living at home and regularly attending senior citizens' centers in New Haven. After testing, we often gave a questionnaire having to do with the subjects' health and occupational history. Under the circumstances of our subject selection and testing, the questionnaires have revealed no striking correlations. Among the questions asked have been the following: 1) Do you have a problem tasting? 2) Do you have a problem smelling? 3) Have you noticed changes in tastes of foods? 4) Do you enjoy food? Of 276 elderly subjects, 17% answered yes to one or more of questions 1-3 and/or no to question 4. Only 5.8% of the total complained of weakened food enjoyment all or some of the time. Several were unable to say why. Some blamed a lifelong lack of interest in food; others, restricted diets, expense of foods, denture problems, etc. In contrast, the great majority (about 260 persons) rated the pleasure of eating with enthusiasm. Of 262 young subjects, 10% answered yes to one or more of questions 1-3 and/or no to question 4, and only four (1.5%) complained of food. Considering the losses involved, the rate of elderly complaining seems low, especially compared with much higher rates from institutionalized persons (for example, up to 33%). The reasons may or may not have to do with sensory factors, but the conclusion seems justified that a persons may profoundly enjoy the pleasures of food and drink despite a weakening of the nasal components involved.

Adolescent↗
PubMed1989

Click evoked otoacoustic emissions compared with brain stem electric response.

The hearing of 346 babies taken largely from a neonatal intensive care unit has been tested by otoacoustic emissions and brain stem electric response audiometry. A total of 336 (97%) of the babies have been followed up by hearing tests from the age of 8 months. The otoacoustic emission test has been found to be practical with a mean test time of 12.1 minutes compared with 21.0 minutes for brain stem electric response. An otoacoustic emission was recorded bilaterally in 274 (79%) babies. Twenty of the 21 surviving infants who failed brain stem electric response in the neonatal period did not produce an emission. It is concluded that the otoacoustic emission test would make a good first screen to be followed by the brain stem electric response if no otoacoustic emission was present. There is poor agreement between the test results in the neonatal period and those of the follow up period, however, indicating the need for continuous monitoring of those babies failed by brain stem electric response.

Acoustic Stimulation↗
PubMed1989

Peripheral neuropathy in primary Sjögren's syndrome.

Sjögren's syndrome (dryness of eyes, mouth, and other mucous membranes) may be associated with disease of joints, blood, internal organs, skin, and central and peripheral nervous systems. We reviewed 33 cases of primary Sjögren's syndrome and peripheral neuropathy evaluated by neurologic examinations and EMG at the Mayo Clinic from 1976 to 1988, and studied sural nerve biopsy specimens in 11 of them. Symmetric sensorimotor polyneuropathy occurred most frequently, followed by symmetric sensory neuropathy. Autonomic neuropathy, mononeuropathy, or cranial neuropathy (especially trigeminal neuropathy) was superimposed on generalized neuropathy in approximately one-fourth of patients. The course generally was slowly progressive, except for a few patients who may have improved with prednisone therapy. Although spinal ganglion involvement might have accounted for some of the clinical and neurophysiologic findings, we found evidence that necrotizing vasculitis was involved in fiber degeneration. All nerve biopsies revealed perivascular inflammatory infiltrates and other vessel abnormalities, which were diagnostic in two cases and strongly suggestive of necrotizing vasculitis in six cases. Axonal degeneration predominated over demyelination and sometimes was focal or multifocal. In neuropathy of unknown cause, particularly if it is sensory, autonomic, or involves trigeminal nerve, consider Sjögren's syndrome.

Adult↗
PubMed1989

Temperature and the two-point threshold.

Studies dating back to 1834 have shown that the temperature of objects contacting the skin can substantially intensify their apparent pressure on the skin. Later research demonstrated qualitatively that object temperature can also sharpen the spatial acuity of the skin as revealed by gap perception (two-point and two-edge thresholds). Pressure intensification and sharpening probably relate intimately. The present experiments sought to provide several more accurate and parametric extensions of thermal sharpening: (1) sharpening can improve tactile spatial acuity by as much as 60%, but the degree of sharpening is graded as a function of deviation of stimulator temperature from normal (neutral) skin temperature; (2) thermal sharpening seems to characterize the body surface since it takes place freely in forearm, forehead, and palm; local differences do, however, become apparent; (3) large thermal sharpening can even occur when one tip of the stimulator is warm, the other cold; and (4) thermal sharpening is easily captured by experiment and is basically the same in magnitude whether assessed by modern forced-choice procedure (controlled criterion) or by the more traditional procedures (uncontrolled criterion) used for more than a century before the advent of signal detection theory. Various arguments are put forth here and elsewhere to suggest that both thermal intensification of pressure sensation and thermal sharpening of gap perception result from direct thermal stimulation of mechanoreceptors and/or polymodal nociceptor networks; neither phenomenon yeilds readily to a "cognitive" interpretation.

Attention↗
PubMed1988

Somatosensory evoked potentials: lack of value for diagnosis of thoracic outlet syndrome.

Twenty patients with thoracic outlet syndrome (TOS) seen at the Mayo Clinic between October 1984 and November 1985 were studied prospectively with routine nerve conduction studies, concentric needle examination, and bilateral median and ulnar somatosensory evoked potentials (SEPs). Results of nerve conduction studies and needle examination were abnormal in 30% of the patients, one patient having a reduced ulnar sensory nerve action potential amplitude and five others having neurogenic motor unit potential changes in the hand muscles. Ulnar SEPs were abnormal in three patients (15%), and median SEPs were abnormal in one patient, who also had abnormalities in ulnar SEPs. In patients with TOS, routine nerve conduction studies and needle examination were the most helpful electrophysiologic studies in excluding more common conditions. The routine use of ulnar SEPs in the evaluation of patients with TOS is probably not worthwhile.

Adult↗
PubMed1988

Absence of long term pulmonary sequelae after mild meconium aspiration syndrome.

To assess residual damage from meconium aspiration syndrome (MAS), we studied 12 children, ages 6 to 9 years, an average of 7.4 years after injury. Our sample consisted of mildly affected patients, only one having required intubation and mechanical ventilation in the acute phase of illness. In each child we measured FVC, FEV1, PEFR, MMEFR, VisoV, lung volumes by plethysmography, DLCO and calculated FEV1/FVC and RV/TLC. Methacholine bronchial challenge was performed and the PD20 was calculated. These results were compared with those obtained from a group of 12 normal children studied in our laboratory. No significant difference was found for pulmonary function parameters studied, except for VisoV which was greater in MAS patients than normals (P less than 0.02). Given the inherent high degree of variability with VisoV, we were not able to ascribe this isolated finding to be indicative of small airway disease in these asymptomatic patients. We conclude that patients with mild to moderate initial insult from MAS show an absence of pulmonary sequelae when tested at an average of 7.4 years of age.

Bronchial Provocation Tests↗
PubMed1988

The nasal valve: a physiological and clinical study.

Fifteen subjects underwent nasal pressure gradient studies to determine the resistance profile of the nose. Seventy-nine per cent of nasal resistance to airflow occurred in the segment 0 cm.-2.8 cm. from the posterior margin of the anterior nares. The greater part of this resistance (43 per cent) occurred in the segment 1.5 cm.-2.8 cm. within the nose, and this area approximated to the site of the pyriform aperture. Eighteen patients underwent a trial of radical trimming of the inferior turbinates (12 patients) versus anterior trimming of the inferior turbinates (6 patients). Both operations produced a similar fall in nasal resistance to airflow, confirming that the region of the pyriform aperture was the site of maximum nasal resistance. Whereas the radical operation significantly reduced the sensation of nasal obstruction, the anterior operation did not. The results of the study are discussed with reference to previous work on the subject.

Adolescent↗
PubMed1988

A critical investigation of the measurement of the force required to dilate the human uterine cervix.

A system for objectively analysing the forces of dilation of the human uterine cervix was devised using a force sensing device linked to a BBC microcomputer. The computer program allowed easy recording, storage and analysis of force/time curves obtained from the passage of tapered dilators through the cervix. A new design of dilator gave a smoother force/time curve. These force/time curves were analysed. Six indices: peak force, end force, area to peak, area to end the ratio of the peak and end forces recorded from the passage of the two largest and two smallest dilators, were compared. Area measurement was subject to artefact and rejected. Peak and end force measurements gave the best separation between parous and nulliparous patients. The peak force was judged to be the better as it was found to be easier to define than end force.

Biophysical Phenomena↗
PubMed1988

Carpal tunnel syndrome in Rochester, Minnesota, 1961 to 1980.

The incidence of carpal tunnel syndrome in the population of Rochester, Minnesota, from 1961 through 1980 was determined by use of the medical records-linkage system of the Rochester Epidemiology Program Project at the Mayo Clinic; 1,016 patients (1,600 affected hands) were identified. Incidence (cases per 100,000 person-years) was 99 (crude) overall, whereas the age-adjusted rates were 52 for the men, 149 for the women, and 105 for both sexes combined. Age-adjusted incidence rates increased from 88 during the 1961 to 1965 quinquennium to 125 during the 1976 to 1980 quinquennium; these rates probably reflect better recognition rather than a true increase in incidence rates. Age-specific rates generally increased with age in men, whereas in women a peak was reached in the 45 to 54 age group.

Adolescent↗