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[Results of surgical treatment of common peripheral nerve lesions of the upper extremities].

The results of operative treatment and clinical as well as electrodiagnostic findings are discussed in 68 cases. In about one half of our cases a carpal tunnel syndrome was found with excellent outcome of the operation in 93,6%, with fairly good outcome in the rest of the cases. In 14 of the patients studied a sulcus nervi ulnaris syndrome was seen, 9 of them showing excellent improvement after operative neurolysis was performed. Motor function improved in 8 out of 11 traumatic nerve dissections; Restitutio ad integrum was seen in incomplete lesions of the brachial plexus only, useful recovery of motor and sensory functions in 7 out of 10 patients with total plexus lesions. Regarding these good results of operative treatment of mechanical lesions of the peripheral nerves an exact clinical and neurophysiological examination has to be done for diagnosing and localizing those peripheral nerve affections.

Adult↗

Changes in peripheral and central nerve conduction with aging.

An electrophysiological study was made of 30 normal subjects aged 20 to 70 years. Routine methods were used to measure peripheral motor and sensory functions of the posterior tibial nerve. This nerve was then stimulated at the ankle and recordings made simultaneously over the thoraco-lumbar spine, cervical spine and central sensory cortex. Peripheral and central potentials were reproducibly recorded at each site in all subjects. Peripheral nerve motor and sensory potential amplitudes fell significantly with age, as did the amplitude of the thoraco-lumbar potential. Cervical and central potential amplitudes did not change significantly with age. The peak latencies of thoraco-lumbar, cervical and central potentials all showed a significant increase with age. In addition, when 'central conduction time' was calculated by subtracting thoraco-lumbar or cervical latency from the latency of the cortical potential, a significant prolongation with increasing age was still seen, especially in more rostral pathways.

Adult↗

Comparison of vibrotactile thresholds with physical examination and electrophysiological assessment.

Measurement of cutaneous vibrotactile thresholds may be useful for assessment of the functional integrity of the somatosensory system. To validate a rapid method of determining vibrotactile thresholds that uses a commercially available electromechanical device, vibrotactile thresholds were compared with standardized physical examination findings of sensory function and electrophysiological parameters in 79 patients referred to the Mount Sinai Hospital Neurophysiology Laboratory for clinical electrophysiological evaluation. A statistically significant monotonic association between graded physical examination of vibration perception and vibrotactile threshold was observed for all digits tested in the upper and lower extremities. Statistically significant associations were also observed between vibrotactile thresholds and a variety of electrophysiological measures of the median, ulnar, tibial, peroneal, and sural nerves. The strongest associations were observed between great toe vibrotactile thresholds and late response latencies measured in nerves in the lower extremities. Determination of vibrotactile thresholds may be useful in settings where quantitative measures of large fiber nerve function are desirable and electrophysiological study is not feasible.

Action Potentials↗

The water absorption response: a behavioral assay for physiological processes in terrestrial amphibians.

Terrestrial amphibians take up water by abducting the hind limbs and pressing a specialized portion of the ventral skin to a moist surface, using a characteristic behavior called the water absorption response. An assay of the water absorption response was used to quantify physiological factors associated with thirst and water uptake. Dramatic changes in the water absorption response resulted from subtle changes in hydration state and from altering the reserve water supply in the urinary bladder. The water absorption response could be induced by intraperitoneal and intracerebroventricular injection of angiotensin II, demonstrating that components of the renin-angiotensin system on both sides of the blood-brain barrier have a dipsogenic function in amphibians. These experiments also demonstrated that the water absorption response could be influenced by changes in barometric pressure. Toads avoided the water absorption response on hyperosmotic substrates, and behavioral experiments showed that the amphibian skin served a sensory function similar to that of the lingual epithelium of mammals. The water absorption response assay has enormous potential as a tool for the investigation of physiological processes and sensory capabilities of amphibians.

Absorption↗

Regulation of protein kinase C activity by sensory deprivation in the olfactory and visual systems.

Environmental regulation of sensory function has provided an important model of plastic mechanisms mediating neural information processing. To define potential commonalities in information processing in different systems, we investigated molecular changes elicited by sensory deprivation in the developing rat olfactory and visual systems. Protein kinase C (PKC), an intracellular messenger implicated in synaptic plasticity and memory, was analyzed. Initial, developmental studies indicated that PKC activity in the soluble and particulate fractions of the olfactory bulb increased three- to fourfold from birth to 3 months of age. Unilateral olfactory deprivation prevented the developmental increase in both soluble and particulate PKC activities in the ipsilateral olfactory bulb and piriform cortex, the second-order relay. Phorbol ester binding localized PKC to intrinsic neuronal populations and their dendrites in the control and deprived bulbs. Moreover, PKC was similarly lower in the visual cortex of dark-reared rats than in light-reared controls. The changes in PKC were region specific, as activity was unchanged by either treatment in the parietal cortex, a control area that does not process primary olfactory or visual information. Our results suggest that the important intracellular messenger, PKC, is similarly regulated in entirely different sensory systems by different environmental stimuli. Consequently, different sensory systems may use common molecular mechanisms to process information.

Animals↗

CCK1 antagonists: are they ready for clinical use?

Cholecystokinin (CCK) is a peptide hormone which is found both in the gastrointestinal tract throughout the human small intestine and nerves in the myenteric plexus of the enteric nervous system and in the central nervous system. This dual location constitutes the anatomical basis for this in functions as a hormone and a neurotransmitter implicated in the regulation of both systems. CCK regulates not only motor functions in the gastrointestinal tract like lower oesophageal sphincter relaxation, gastric secretion and emptying, gall bladder contractility and bile secretion into the duodenum, intestinal and colonic motility, but also sensory functions and plays a role in the regulation of food intake. These effects are mediated through selective receptors CCK1 and CCK2. Over the last few years, research has focused on understanding the role of CCK, its receptors with antagonists at the biological, pharmacological, clinical and therapeutic level. As far as the CCK1 antagonists is concerned, important inroads have been made in the potential role of these antagonists in the treatment of GERD, IBS and pancreatitis. They have also shown encouraging results in sphincter of Oddi dysfunction and some gastrointestinal cancers. This review focuses on the recent ad vances of the biological role of CCK and their CCK1 antagonists: their current basic and clinical status in gastroenterology, with particular emphasis on the potential therapeutic role of the CCK1 antagonists and future research directions.

Cholecystokinin↗

Motor and sensory cortex in humans: topography studied with chronic subdural stimulation.

Classic neurosurgical teaching holds that once the Rolandic fissure (Rf) has been located, there are distinct differentiated primary motor and sensory functional units confined within a narrow cortical strip: Brodmann's Areas 4 and 6 for primary motor units in front of the Rf and 3, 1, and 2 for sensory units behind the Rf. To test this assumption, we examined in detail the records of cortical mapping done by electrical stimulation of the cerebral cortex via implanted subdural electrode grids in 35 patients with seizure disorders. Of 1381 stimulations of the electrode sites, 346 (25.1%) produced primary motor or motor-arrest and sensory responses in contralateral body parts: 56.8% were primary motor responses; 16.2% were motor-arrest; 22.5% were sensory; and the remaining 4.5% were mixed motor and sensory responses. Two-thirds (65.9%) of the primary motor responses were located within 10 mm of the Rf, and the remaining one-third (34.1%) were more than 10 mm anterior to the Rf or were posterior to the Rf. Furthermore, in the patient group with brain lesions, fewer than one-third (28.1%) of the responses were within the 10-mm narrow anterior strip. Our study reconfirmed that a significant number--at least one-third--of motor responses are distributed outside the classic narrow cortical strip. In patients with brain lesions, the motor representation is further displaced outside the narrow strip. This finding indicates that primary motor cortex may extend beyond the gyrus immediately anterior to the Rf.

Adolescent↗

A cohort study found good respiratory, sensory and motor functions decreased mortality risk in older people.

BACKGROUND AND OBJECTIVE: The main aims of this study were to evaluate the separate and joint effects of respiratory, sensory, and psychomotor function, muscle strength, and mobility in predicting mortality in older men and women, and to find a way to control multicollinearity in a multivariate Cox regression model. METHODS: Mortality was followed for 10 years (1990-2000) in an entire cohort of 75-year-old residents of the city of Jyvaskyla, Finland (born in 1914; N=388). Cox regression models and principal component estimation were employed to study the association between the covariates and mortality. RESULTS: The study indicated that, after adjustment for fatal diseases and cognitive capacity, vital capacity, tapping rate, muscle strength, and walking speed predict mortality in elderly men and women to a similar extent. The hazard ratio for mortality for those in the lowest tertile of the principal component representing all the significant physiological functions was from three to four times higher than for those in the highest tertile. CONCLUSION: Our results suggest that a poor level in any of the measured functions has a similar impact on the risk for mortality, which is further increased by combining the different results. No single, dominant predictor of mortality emerged.

Aged↗

Driving avoidance and functional impairment in older drivers.

The purpose of this study was to examine the association between visual and cognitive impairment in older drivers and their avoidance of potentially challenging, driving situation. A group of 257 older drivers participated in assessments of visual sensory function, eye health and cognitive function including the useful field of view test, and completed a structured questionnaire on driving exposure and how frequently they avoided challenging driving situations. Results replicated earlier studies showing that many older drivers limit their exposure to driving situations which are generally believed to be more difficult (e.g. rain, night, heavy traffic, rush hour). Furthermore, older drivers with objectively determined visual and/or attentional impairments reported more avoidance than those free of impairments; those with the most impairment reported avoiding more types of situations than other less impaired or non-impaired drivers. Older drivers with a history of at-fault crashes in the prior five years reported more avoidance than those who had crash-free records. Future research should evaluate the potentially beneficial role of self-regulation in enhancing older driver safety, particularly in those older drivers with visual and attentional processing impairments who have elevated crash risk.

Aged↗

Tactile functions of mechanoreceptive afferents innervating the hand.

Four types of mechanoreceptive afferents innervate the glabrous skin of the hand. Evidence from more than three decades of combined psychophysical and neurophysiological research supports the idea that each afferent type serves a distinctly different sensory function and that these functions explain most of tactual perceptual function. The available evidence supports the following hypotheses: (1) The slowly adapting type 1 system provides the information on which form and texture perception are based. (2) The cutaneous rapidly adapting system provides information about minute skin motion and, thereby, plays a critical role in grip control. (3) The Pacinian system is responsible for the detection and perception of distant events by vibrations transmitted through objects, probes, and tools held in the hand. (4) The slowly adapting type 2 system provides information for the perception of hand conformation and for the perception of forces acting on the hand. The authors review the evidence on which these hypotheses are based. They also review the role of proprioceptive afferents in the perception of hand conformation because they appear to play a significant role along with cutaneous afferents.

Afferent Pathways↗

Effect of prolonged gastric distension on motor function of LES and of proximal stomach.

Gastric distension is a potent stimulus of transient lower esophageal sphincter (LES) relaxation. To investigate the time effect of prolonged gastric distension on the rate of transient LES relaxations, LES pressure, and the motor and sensory functions of the proximal stomach, we performed a continuous isobaric distension of the proximal stomach at the 75% threshold pressure for discomfort for 2 h in seven healthy subjects. A multilumen assembly incorporating a sleeve and an electronic barostat was used. The rate of transient LES relaxations (n/30 min) was constant during the first hour [4.1 +/- 1.2 (0-30 min) and 5.4 +/- 1.1 (30-60 min)] but markedly decreased (P < 0.05) in the second hour [2.1 +/- 0.5 (60-90 min) and 2.3 +/- 0.9 (90-120 min)], whereas LES pressure, baseline volume and volume waves within the gastric bag, hunger, and fullness did not change throughout the experiment. It is concluded that the rate of transient LES relaxations decreases with time during prolonged gastric distension, thus suggesting that this type of stimulus should not be used in sequential experimental conditions.

Adult↗

Mapping of secondary somatosensory cortex activation induced by vibrational stimulation: an fMRI study.

Sensory functional MRI was performed in seven normal volunteers at 1. 5 T using a vibratory stimulus applied to the pad of the first finger of the left hand. The data was normalized to a standard atlas, and individual and group statistical parametric maps were computed. Robust bilateral activation was demonstrated in the secondary somatosensory cortex (SII), indicating a bilateral representation of SII in humans. Greater maxima and activation volumes were achieved in contralateral SII as compared to SI. Sensory fMRI can provide a sensitive assay for probing the nature and function of SII in vivo.

Adult↗

Peripheral synaptic contacts at mechanoreceptors in arachnids and crustaceans: morphological and immunocytochemical characteristics.

Two types of sensory organs in crustaceans and arachnids, the various mechanoreceptors of spiders and the crustacean muscle receptor organs (MRO), receive extensive efferent synaptic innervation in the periphery. Although the two sensory systems are quite different-the MRO is a muscle stretch receptor while most spider mechanoreceptors are cuticular sensilla-this innervation exhibits marked similarities. Detailed ultrastructural investigations of the synaptic contacts along the mechanosensitive neurons of a spider slit sense organ reveal four important features, all having remarkable resemblances to the synaptic innervation at the MRO: (1) The mechanosensory neurons are accompanied by several fine fibers of central origin, which are presynaptic upon the mechanoreceptors. Efferent control of sensory function has only recently been confirmed electrophysiologically for the peripheral innervation of spider slit sensilla. (2) Different microcircuit configuration types, identified on the basis of the structural organization of their synapses. (3) Synaptic contacts, not only upon the sensory neurons but also between the efferent fibers themselves. (4) Two identified neurotransmitter candidates, GABA and glutamate. Physiological evidence for GABAergic and glutamatergic transmission is incomplete at spider sensilla. Given that the sensory neurons are quite different in their location and origin, these parallels are most likely convergent. Although their significance is only partially understood, mostly from work on the MRO, the close similarities seem to reflect functional constraints on the organization of efferent pathways in the brain and in the periphery.

Animals↗

Biofeedback training in disordered defecation. A critical review.

For 20 years now, biofeedback applications in the treatment of fecal incontinence and, more recently, chronic constipation in adults have proven that improvement of anorectal function can be achieved in a majority of patients. Despite this evidence, the definitive mode of action of biofeedback training remains obscure but may include improvement of both motor and sensory functions of the anorectum. In addition, behavioral modification of individual defecatory behavior in these patients may be effective as well. The long-term results of such treatment need to be tested in future research.

Anal Canal↗

[Antireflux therapy--more than acid reduction?].

Because gastroesophageal reflux disease (GERD) is a motility disorder, acid reduction with proton pump inhibitors (PPI) remains a symptomatic therapy with a recurrence rate of over 90% after discontinuation of acid suppression. This "therapeutic dilemma" becomes obvious in patients not responding sufficiently to the conventional medication (therapy resistance, necessity of high PPI doses, volume reflux). In this manuscript we analyze additional factors that may play a role in the pathogenesis and interpretation of GERD. These additional factors include gastroesophageal motility and esophageal barrier functions as well as duodenogastroesophageal reflux and Helicobacter pylori infection. In addition, basic problems in interpretation of therapeutic success such as placebo effect, spontaneous remission of GERD, the role of sensory function and subjective interpretation of symptoms and the overlap between physiological and pathological reflux as well as functional disorders will be discussed.

Antacids↗

The measurement of capsaicin-sensitive sensory nerve fiber function in elderly patients with pain.

The present study was undertaken to investigate the possible involvement of peripheral nociceptors in 3 diagnostic categories of elderly patients with chronic pain. The 3 diagnostic groups consisted of: chronic lower lumbar pain of degenerative musculoskeletal etiology (LLP), post-herpetic neuralgia (PHN) and pain of non-organic origin in a group with a predominantly psychiatric disorder (PPD). The last group had pain confined to the trunk. All patients documented subjective pain using a visual analogue scale and an 8-item pain descriptor scale. Topical application of capsaicin was used to induce an axon reflex flare in 25 patients with pain and 29 control subjects. Three forms of measurement were used: flare size measured by tracing and by laser Doppler flowmetry, latency to onset of increased skin blood flow and blood flux. The groups with LLP and PHN had reduced flares at the affected site by all 3 measures, whereas no decrease was observed in the PPD group. No significant difference was found between groups when tested on a control site remote from the affected area using the 3 forms of measurement. We suggest that an alteration in the function of capsaicin-sensitive sensory fibers could be related to the subjective report of subacute and chronic pain in diagnostic groups such as LLP and PHN where there is a known organic cause.

Aged↗

Sensory dysfunction in burning mouth syndrome.

Our preliminary observations on a small group of burning mouth syndrome (BMS) patients indicated a change in the non-nociceptive, tactile sensory function in BMS and provided evidence for the hypothesis of a neuropathic etiology of BMS. In the present clinical study on a group of 52 BMS patients, we used quantitative sensory tests (QST) in addition to the blink reflex (BR) recordings in order to gain further insight into the neural mechanisms of BMS pain. Based on electrophysiologic findings, the BMS patients could be grouped into four different categories: (1) The results of the BR were suggestive of brainstem pathology or peripheral trigeminal neuropathy in ten (19%) patients. In most of the cases, the abnormalities in the BR seemed to represent subclinical changes of the trigeminal system. (2) Increased excitability of the BR was found in the form of deficient habituation of the R2 component of the BR in 11 (21%) of the patients. Two of these patients also showed signs of warm allodynia in QST. (3) One or more of the sensory thresholds were abnormal indicating thin fiber dysfunction in altogether 35 patients (76%) out of the 46 tested with QST. Thirty-three of these patients showed signs of hypoesthesia. (4) There were only five patients with normal findings in both tests. The present findings with strong evidence for neuropathic background in BMS will hopefully provide insights for new therapeutic strategies.

Adult↗

Embryonic assembly of a central pattern generator without sensory input.

Locomotion depends on the integration of sensory information with the activity of central circuitry, which generates patterned discharges in motor nerves to appropriate muscles. Isolated central networks generate fictive locomotor rhythms (recorded in the absence of movement), indicating that the fundamental pattern of motor output depends on the intrinsic connectivity and electrical properties of these central circuits. Sensory inputs are required to modify the pattern of motor activity in response to the actual circumstances of real movement. A central issue for our understanding of how locomotor circuits are specified and assembled is the extent to which sensory inputs are required as such systems develop. Here we describe the effects of eliminating sensory function and structure on the development of the peristaltic motor pattern of Drosophila embryos and larvae. We infer that the circuitry for peristaltic crawling develops in the complete absence of sensory input; however, the integration of this circuitry into actual patterns of locomotion requires additional information from the sensory system. In the absence of sensory inputs, the polarity of movement is deranged, and backward peristaltic waves predominate at the expense of forward peristalsis.

Animals↗