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Results for “sensory function”

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At least 343 records · Page 19Linked to original sources

PubMed2007

Contralateral C7 transfer for the treatment of brachial plexus root avulsions in children - a report of 12 cases.

PURPOSE: To retrospectively determine the risks and benefits of contralateral C7 nerve root transfer in infants and children. METHODS: In 12 infants and children with brachial plexus root avulsions from birth injury or other trauma, the common trunk of the contralateral C7 root was transferred to the trunk, division, cord, or nerve branch(es) on the affected side with 2 different types of interposition grafts. The surgery was performed in 1 stage for 5 patients and in 2 stages for 7 patients. RESULTS: Patients were followed up for a mean of 42 months, with a minimum of 21 months. Noteworthy function (> or = M2+, modified British Medical Research Council grading system) was gained in 10 of 12 patients and sensory function (> or = S3, British Medical Research Council grading system) was gained in all patients. Improvements in strength and sensation were accompanied by little synchronous motion and sensibility changes in the donor limb in 7 children, to whom the repaired nerves were those innervating the shoulder and/or elbow or both the musculocutaneous and median nerves. In addition to slight damage to the sensory function of the median nerve, 2 infants also had temporarily reduced shoulder abduction on the healthy side. CONCLUSIONS: For contralateral C7 transfer in infants and children with brachial plexus root avulsions, the deficit created by the procedure is minimal and motor and sensory function is gained. Transfer of the contralateral C7 root to different nerves for a child may improve the quality of functional recovery. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.

Brachial Plexus Neuropathies↗

PubMed1995

Diencephalic changes in traumatic brain injury: relationship to sensory perceptual function.

Magnetic resonance (MR) imaging scans of 33 traumatically brain-injured (TBI) patients were compared quantitatively to MR scans of controls matched for age and gender. Quantitative estimates of thalamic, internal capsule, and third ventricle morphology were obtained in each TBI patient. Comparisons were made to normal control subjects and revealed significant reduction in thalamic volume with corresponding increase in third ventricle. Measurements of internal capsule reflected nonsignificant changes. Significant correlations were observed between sensory-perceptual functioning, as measured by the Reitan-Kløve Sensory-Perceptual Exam, and thalamic volume in TBI patients. A decrease in thalamic volume was associated with an increase in sensory-perceptual errors.

Adolescent↗

PubMed2005

Delay-period activity in the prefrontal cortex: one function is sensory gating.

The prefrontal cortex (PFC) contributes to working memory functions via executive control processes that do not entail the storage, per se, of mnemonic representations. One of these control processes may be a sensory gating mechanism that facilitates retention of representations in working memory by down-regulating the gain of the sensory processing of intervening irrelevant stimuli. This idea was tested by scanning healthy young adults with functional magnetic resonance imaging while they performed a delayed face-recognition task. The 2 x 2 factorial design varied the factors of Memory (present, absent) and Distraction (present, absent). During memory-present trials, target and probe stimuli were individual gray-scale male faces. Memory-absent trials were identical, except that they employed the same recurring female faces (denoting a "no memory" trial). Distraction-present trials featured rapid serial visual presentation of bespectacled male faces during the two middle seconds of the delay. The first step of the analyses identified dorsolateral PFC (dlPFC) and inferior occipitotemporal cortex (IOTC) voxels exhibiting delay-period activity in memory-present/distraction-absent trials, that is, the "unfilled" delay. Within these voxels, distraction-evoked activity in the dlPFC was markedly higher during trials that required the concurrent short-term retention of information than on those that did not, whereas the opposite effect was seen in the IOTC. These results are consistent with the view that processes related to sensory gating account for a portion of the delay-period activity that is routinely observed in the dlPFC.

Adult↗

PubMed1988

State of health and its association with death among old people at three-years follow-up. I. Lung function, circulation, sensory and motor apparatus.

A general medical examination was performed of 569 Copenhagen inhabitants aged 75, 80, and 85 years in the participants' own homes as part of an epidemiological, sociomedical intervention study. The present report contains the results of this examination regarding lung function, circulation, sensory, and motor apparatus. Curves are presented expressing the normal peak expiratory flow rate (PEFR) for men and women 75-85 years old. More men than women had a compromised lung function. Regarding circulation and motor apparatus, more women and 85-year-olds showed impairments. Functional vision and hearing declined with age, but no significant differences could be demonstrated between men and women, although a preponderance of women tended to show hearing disability. Institutionalised participants were more inclined to have impairment of lung function and sight and to walk with difficult. Gait disturbances and impairment of vision were the objective health measurements most strongly related to death at follow-up after three years.

Aged↗

PubMed1977

Steady-state evoked potentials.

The advantages of steady-state EP recording include (1) speed in assessing sensory function in normal and sick infants (e.g., in amblyopia) and in sick adults (e.g., in multiple sclerosis); (2) monitoring certain activities of sensory pathways that do not intrude into conscious perception; (3) rapidly assessing sensory function when a large number of subjects must be tested (e.g., in refraction); (4) objective measurement at very high suprathreshold levels where psychophysical methods are difficult or ineffective; (5) rapidly assessing sensory function in normal subjects when EP variability and nonstationarity preculde lengthy experiments; and (6) proving a speedy objective equivalent to behavioral test in animals.

Adult↗

PubMed1989

Somatosensory evoked potentials for orthopaedic spine trauma.

Monitoring somatosensory evoked potentials (SSEPs) for intraoperative assessment of spinal cord activity provides a reliable and valid measure of sensory function during manipulation of structures placing cord function at risk. We describe a multichannel technique with artifact reductions that has proved successful in 415 spine cases including 146 posttraumatic injuries. Accurate prediction of sensory function in near or at 100% of cases is possible. No patient has recovered with less than the predicted sensory function. Statistics and cases are presented. A professional-level consultant role for SSEP monitoring is suggested as necessary for valid use of the technique.

Adult↗

PubMed1987

Bootstrap variance estimators for the parameters of small-sample sensory-performance functions.

The bootstrap method, due to Bradley Efron, is a powerful, general method for estimating a variance or standard deviation by repeatedly resampling the given set of experimental data. The method is applied here to the problem of estimating the standard deviation of the estimated midpoint and spread of a sensory-performance function based on data sets comprising 15-25 trials. The performance of the bootstrap estimator was assessed in Monte Carlo studies against another general estimator obtained by the classical "combination-of-observations" or incremental method. The bootstrap method proved clearly superior to the incremental method, yielding much smaller percentage biases and much greater efficiencies. Its use in the analysis of sensory-performance data may be particularly appropriate when traditional asymptotic procedures, including the probit-transformation approach, become unreliable.

Animals↗

PubMed1981

Measurement of integrated sensory-motor function following brain damage by a computerized preview tracking task.

A preview tracking task has been developed which has particular application to neurological assessment and rehabilitation. Generated and monitored by a graphic display computer, it permits accurate global quantification of the upper-limb sensory-motor system. The incorporation of 'preview' into the tracking task is considered to significantly increase its effectiveness and relevance in relation to normal daily activities. Applied to three groups of normal subjects, several features of normal psychomotor performance and learning were identified or verified: hand dominance is not significant in overall arm control; learning does not completely plateau; increase in age (15-59 years) results in only a minor overall decrement in performance; an initial wide performance distribution decreases dramatically in subsequent sessions. Applied to brain-damaged patients, particularly head injury or stroke, the preview tracking task allows assessment at regular intervals enabling sensory-motor recovery curves to be generated. The potential of this technique, to help determine the efficacy of therapeutic procedures on the recovery process, is illustrated with the presentation of results from three brain-damaged patients demonstrating zero, significant and disjointed recovery of sensory-motor function. The usefulness of the preview tracking task can be expanded by combination with a less frequently applied but more component specific neurological assessment battery.

Adolescent↗

PubMed1985

Mechanisms of depletion of substance P by capsaicin.

Capsaicin is a neurotoxin that can deplete sensory nerves of their content of substance P and interfere with certain sensory functions, such as responses of animals to noxious heat stimuli. In adult guinea pigs, a species that is susceptible to the effects of capsaicin on both substance P content and sensory function, capsaicin induces selective depletion of substance P from dorsal root ganglia and the dorsal spinal cord, sites of the cell bodies and central terminals of primary afferent neurons, respectively. As the onset of thermal analgesia in guinea pigs precedes depletion of substance P, direct neural actions of capsaicin probably account for its effects on sensory function. Capsaicin interferes with the retrograde transport of nerve growth factor (NGF) to the cell bodies of sensory nerves. Decreased availability of NGF at the site of neural protein synthesis leads to decreased synthesis of substance P. After failure of synthesis of substance P, the content of the peptide in sensory nerves gradually decreases until depletion occurs.

Analgesia↗

PubMed2007

Modelling neural informational propagation and functional auditory sensory memory with temporal multi-scale operators.

In this paper we prove that both diffusion and the leaky integrators cascade based transport mechanisms have as their inherent property the effect of temporal multi-scaling. The two transport mechanisms are modeled not as convolution based algorithms but as causal physical processes. This implies that propagation of information through a neural map may act as a mechanism for achieving temporal multi-scale analysis in the auditory system. Specifically, we are interested in the effects of such a transport process on the formation and the dynamics of auditory sensory memory. Two temporal models of information propagation are discussed and compared in terms of their ability to model auditory sensory memory effects and the biological plausibility of their structure: the causal diffusion based operator (CD) and the leaky integrator cascade based operator (LINC). We show that temporal multi-scale representations achieved by both models exhibit the effects similar to those of auditory sensory memory (filtering, time delay and binding of information). As regards higher-level functions of auditory sensory memory such as change detection, the LINC operator seems to be a biologically more plausible solution for modeling temporal cortical processing.

Algorithms↗

PubMed2001

Effect of methyl prednisolone on sensory motor functions in tuberculous meningitis.

A prospective hospital based study was undertaken to study the effect of methyl prednisolone therapy on sensory and motor functions in tuberculous meningitis (TBM). The patients with TB meningitis seen during 1994-1998 were studied. CT scan, motor evoked potential (MEP) to upper and lower limbs; and median and tibial somatosensory evoked potentials (SEP) were carried out in all the patients. Outcome was defined at the end of 3 months into poor, partial or complete recovery on the basis of Barthel index score. Inj methyl prednisolone (MPS) 500 mg IV was given to 21 patients followed by oral tapering dose of prednisolone over one month in addition to 4 drug anti-tubercular treatment. The control group comprised of 16 patients who received 4 drugs anti-tubercular therapy without any corticosteroid. These groups were comparable with respect to their age, stage of meningitis, Glasgow coma scale score and radiological findings. In MPS group, CMCT was abnormal in 9 and SEPs in 7 patients. In the control group, these were abnormal in 9 and 5 patients respectively. Three months after the therapy the frequency of improvement, deterioration and stationary evoked potential (EP) changes were also noted in both the groups. Diversity of evoked potential changes were also noted. Evoked potential changes were neither significantly different between the groups nor there was any beneficial effect shown in MPS group at 3 months. On the contrary, the control group fared significantly better than the MPS group. Initial MEP and SEP abnormalities were however related to 3 months outcome (p<0.01).

Adult↗

PubMed1983

Requirement of the cheB function for sensory adaptation in Escherichia coli.

The chemotactic behavior of Escherichia coli mutants defective in cheB function, which is required to remove methyl esters from methyl-accepting chemotaxis proteins, was investigated by subjecting swimming or antibody-tethered cells to various attractant chemicals. Two cheB point mutants, one missense and one nonsense, exhibited stimulus response times much longer than did the wild type, but they eventually returned to the prestimulus swimming pattern, indicating that they were not completely defective in sensory adaptation. In contrast, strains deleted for the cheB function showed no evidence of adaptation ability after stimulation. The crucial difference between these strains appeared to be the residual level of cheB-dependent methylesterase activity they contained. Both point mutants showed detectable levels of methanol evolution due to turnover of methyl groups on methyl-accepting chemotaxis protein molecules, whereas the cheB deletion mutant did not. In addition, it was possible to incorporate the methyl label into the methyl-accepting chemotaxis proteins of the point mutants but not into those of the cheB deletion strain. These findings indicate that cheB function is essential for sensory adaptation in Escherichia coli.

Adaptation, Physiological↗

PubMed2001

Diurnal variation of abdominal motor responses to colorectal distension and plasma cortisol levels in rats.

Most patients with functional bowel disorders complain of daytime symptoms while they remain asymptomatic at night. As symptoms are associated with heightened visceral sensitivity, we hypothesized that circadian fluctuations of the visceral sensory function occur. At four different timepoints (06.00, 12.00, 18.00 and 24.00 h), colorectal distensions (CRD) were performed in fasting conscious male Lewis rats using a balloon catheter and a barostat device. The abdominal wall contractions (behavioural pain response) were assessed during colorectal distension by abdominal wall electromyography (EMG). Plasma levels for endogenous cortisol were determined simultaneously at these timepoints. EMG responses to CRD were significantly (P < 0.05) higher at midnight and in the early morning. Plasma cortisol levels peaked in the evening. In night-active Lewis rats, the behavioural pain response to noxious visceral stimulation is augmented at night and fluctuations of visceral sensitivity are accompanied by circadian changes of plasma concentrations of endogenous cortisol. We conclude that there are marked circadian fluctuations in visceral sensory functions. Thresholds are low during time periods of normal behavioural activity. These findings suggest that fluctuation of the sensory functions may be linked to the circadian variability of symptoms in patients with functional GI disorders.

Abdomen↗

PubMed1987

The correlation between sensory-efferent functions mediated by the capsaicin-sensitive neurons and substance P content of the rat urinary bladder.

The substance P-like immunoreactivity (SP-LI) of the urinary bladder of adult rats was depleted by capsaicin desensitization (50 mg/kg, s.c., 4 days before) or extrinsic denervation (pelvic ganglionectomy) thus indicating its neurogenic sensory origin. SP-LI levels were inversely proportional to the volume threshold for micturition but not to the amplitude of micturition contraction. Moreover SP-LI levels were directly related to the amplitude of the capsaicin- but not field stimulation-induced contraction of the rat isolated bladder. These findings indicate that the SP-LI level of the rat bladder is a useful index for monitoring the dual sensory-efferent functions of the capsaicin-sensitive innervation of this organ.

Animals↗

PubMed1997

Emergence of a powerful connection between sensory and cognitive functions across the adult life span: a new window to the study of cognitive aging?

Six hundred eighty seven individuals ages 25-103 years were studied cross-sectionally to examine the relationship between measures of sensory functioning (visual and auditory acuity) and intelligence (14 cognitive tasks representing a 5-factor space of psychometric intelligence). As predicted, the average proportion of individual differences in intellectual functioning connected to sensory functioning increased from 11% in adulthood (25-69 years) to 31% in old age (70-103 years). However, the link between fluid intellectual abilities and sensory functioning, albeit of different size, displayed a similarly high connection to age in both age groups. Several explanations are discussed, including a "common cause" hypothesis. In this vein, we argue that the increase in the age-associated link between sensory and intellectual functioning may reflect brain aging and that the search for explanations of cognitive aging phenomena would benefit from attending to factors that are shared between the 2 domains.

Adult↗

PubMed1997

Perinatal motor behaviour and neurological outcome in spina bifida aperta.

AIM OF THE STUDY: In the present longitudinal study we investigated the relationship between prenatal motor behaviour and the postnatal neurological sequelae of infants with spina bifida aperta. METHODS AND PATIENTS: Prenatal isolated leg movements and general movements of 13 fetuses/infants with spina bifida aperta were assessed by means of ultrasound recordings, and were compared with: 1. the spinal level of morphological defect (meningo-myelocele), 2. the postnatal motor behaviour, 3. the postnatal sensory function, and 4. the final motor outcome. RESULTS: In all 13 cases studied, the spinal defect was either at thoracic (n = 8) or at lumbal (n = 5) level. All fetuses displayed active leg movements corresponding to the functioning of low lumbal myelum segments (L4-5 in two cases or L5-S1 in 11 cases), despite vertebral defects at high localisation. These leg movements were of normal quality (normal in appearance) and endogenously generated, since no external stimulus was exerted to elicit them. This implies that in fetuses with spina bifida aperta active leg movements can be generated at spinal segments which are located at (n = 1), or under (n = 12) the meningo-myelelocele. Postnatally, for a short period of time (mostly during the first few hours), leg movements related to myelum function at (n = 1) or lower than (n = 7) the spinal defect were detected. However, only in two infants these early leg movements were of normal quality and corresponded with the final motor outcome. In contrast to these early neonatal leg movements, early sensory function was strongly related to the spinal defect (r = 0.76; P = 0.005) and to the final motor outcome (sensory function predicted outcome in all infants of whom follow-up was performed). CONCLUSION: These data on fetuses/infants with spina bifida aperta strongly indicate that a discrepancy exists between the occurrence of prenatal leg movements and the spinal localisation of the meningo-myelocele on the one hand, and between the occurrence of pre- and postnatal leg movements on the other hand (quantity and quality).

Adult↗

PubMed1998

A comparison of sensory nerve function in human, guinea-pig, rabbit and marmoset airways.

We have investigated the role of sensory nerves in regulating airway smooth muscle function in the guinea-pig, marmoset, rabbit and man. Tissue levels of the sensory neuropeptides CGRP and substance P in the airways of the guinea-pig were significantly greater compared with the rabbit and marmoset. The relative order of tissue content was guinea-pig >>> rabbit = marmoset. Marmoset bronchial and tracheal preparations responded weakly to exogenously administered substance P and neurokinin A but contracted to methacholine and demonstrated atropine-sensitive cholinergic responses. In marmoset, rabbit and human airway preparations, capsaicin mediated weak contractile responses to exogenously administered capsaicin. However, high concentrations of capsaicin elicited a relaxation response that was epithelium-independent, cyclo-oxygenase-insensitive, not involving nitric oxide and not dependent on the activation of capsaicin-sensitive afferents. These results suggest that rabbit and marmoset airways respond functionally in a similar way to human airway preparations and maybe more relevant than guinea-pig airways with regard to understanding the role of sensory neuropeptides in airways.

Animals↗

PubMed2004

Alterations of sensori-motor functions of the digestive tract in the pathophysiology of irritable bowel syndrome.

Pathophysiology of irritable bowel syndrome (IBS) is based upon multiple factors that have been organised in a comprehensive model centred around the brain-gut axis. The brain-gut axis encompasses nerve pathways linking the enteric and the central nervous systems and contains a large proportion of afferent fibres. Functionally and anatomically, visceral nerves are divided in to two categories: the parasympathetic pathways distributing to the upper gut through the vagi and to the hindgut, through the pelvic and pudendal nerves, and the sympathetic pathways, arising form the spinal cord and distributing to the midgut via the paravertebral ganglia. Several abnormalities of gut sensori-motor function have been described in patients with IBS. Abnormal motility patterns have been described at the intestinal and colonic levels. Changes in colonic motility are mainly related to bowel disturbances linked to IBS but do not correlate with pain. More recently, visceral hypersensitivity has been recognised as a main characteristic of patients with IBS. It is defined by an exaggerated perception of luminal distension of various segments of the gut and related to peripheral changes in the processing of visceral sensations as well as modulation of perception by centrally acting factors including mood and stress. Viscero-visceral reflexes link the two edges of the brain-gut axis and may account for the origin of symptoms in some pathological conditions. Recent advances in the understanding of the role of myenteric plexus allowed recognition of several neurotransmitters involved at the level of both the afferent and efferent pathways. Targeting the receptors of these neurotransmitters is a promising way for development of new treatments for IBS.

Animals↗