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Results for “sensory function”

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At least 973 records · Page 54Linked to original sources

PubMed1988

Vascular complications in orthopedic surgery.

Vascular complications may be seen secondary to trauma or in the perioperative period following elective surgery. Prompt recognition and correction of these problems are of utmost importance to assure functional viability of the affected extremity. Evaluation may be complicated by the presence of preexisting atherosclerotic occlusive disease in the elderly patient. Relevant points in the history and physical examination include mechanism of injury, preexisting disease, evaluation of motor and sensory function, and presence and character of pulses. Noninvasive vascular studies should be obtained in all patients. Absolute indications for angiography include absent pulses, signs and symptoms of ischemia, a bruit, and a posterior knee dislocation; decreased pulses, a significant hematoma, and proximity of the fracture fragment are relative indications. Controversial issues in the management of combined orthopedic and vascular injuries include the use of internal versus external fixation, the use of prosthetic versus autogenous material, and the need for venous reconstruction. Popliteal artery trauma is still associated with a high limb loss rate, and careful evaluation of knee injuries is necessary. Vascular compromise may also complicate joint replacement surgery. These complications are preventable, and management is greatly simplified by a detailed preoperative evaluation.

Adult↗

PubMed1993

Pharmacological treatment of acute spinal cord injury: current status and future projects.

The multicenter, double-blind, randomized second National Acute Spinal Cord Injury Study (NASCIS 2) was conducted to assess the effectiveness of methylprednisolone in improving neurological function after acute spinal cord injury. At 6 weeks, patients treated within 8 hours of injury with methylprednisolone, given as an initial bolus of 30 mg/kg followed by infusion of 5.4 mg/kg/h over 23 hours, demonstrated significantly greater improvement in motor function and touch sensation than did those receiving either naloxone or placebo. Improvement in pinprick sensation was also greater in the methylprednisolone group. These differences were maintained at 6 months and 1 year after injury. The recovery of motor and sensory function in methylprednisolone-treated patients was found to be due primarily to reductions in the severity of the lesion in the spinal cord itself rather than to improvements in the level of injury or root function. A new trial, NASCIS 3, is evaluating a 48-hour course of methylprednisolone infusion as well as treatment with tirilazad mesylate, an inhibitor of lipid peroxidation without glucocorticoid activity.

Adult↗

PubMed1989

Replantation and revascularization of hands: clinical analysis and functional results of 261 cases.

During the past 4 years we performed 261 replantations and revascularizations on amputated digits and hands in 153 patients. The overall survival rate was 82%. Clean-cut proximal level amputations and hypothermically preserved amputation parts had the highest survival rate. A higher survival rate and more satisfactory results with accelerated return of sensory function correlated with repair of both digital arteries and two veins rather than only one. All patients experienced intolerance to cold, but this was more troublesome in patients with digital replantation in whom only a single artery was repaired. Digital sensibility and joint motion after replantation were better in these patients who had sharp amputations and on whom repairs were carried out in zone III. Return of intrinsic muscle function after hand replantation was poor; however, patient satisfaction with the procedures remained high.

Adolescent↗

PubMed2005

Effect of cochlear integrity on cochlear nucleus neuron glucose metabolism in aged adult broiler chickens.

Abrupt removal of excitatory input is devastating to post-synaptic neurons in normally functioning sensory systems. In both mammalian and avian auditory systems, abrupt temporary or permanent experimental deafferentation stimulates a cascade of changes in central auditory structures that can result in neuron death. Effects of naturally occurring progressive deafferentation on central auditory structure and function have not been fully described. Extensive naturally occurring cochlear damage is found in some aged chickens, despite their regenerative capacity, providing the opportunity to examine the effects of this type of deafferentation on the avian cochlear nucleus (nucleus magnocellularis, NM). Previous evaluation of NM oxidative metabolism using cytochrome oxidase histochemistry revealed that naturally occurring cochlear damage results in down-regulated metabolism in corresponding regions of NM. It is unknown how progressive hair cell damage and loss affects NM glucose uptake. Here, NM glucose metabolism is assessed using 2-deoxyglucose uptake as a marker for metabolic activity in the presence of normal, mildly damaged, severely damaged, and totally damaged cochlear hair cells. Results indicate that while severe and total cochlear damage significantly decrease NM oxidative metabolism, only total damage results in significantly decreased NM glucose metabolism. Results are discussed in the context of functional reorganization and trophic support.

Aging↗

PubMed2000

Effect of modified sham feeding and insulin-induced hypoglycemia on function of the proximal stomach.

BACKGROUND/AIM: Animal experiments have shown that vagal cholinergic stimulation causes an increase in proximal gastric tone, but little is known about the effect of vagal stimulation on proximal gastric motor function in humans. Vagal cholinergic stimulation can be elicited by modified sham feeding (MSF) or by insulin-induced hypoglycemia. The aim of our study was to investigate the effect of MSF and insulin-induced hypoglycemia on the motor and sensory function of the proximal stomach in humans. METHODS: Eight healthy volunteers participated in random order in three experiments: (A) control experiment, (B) MSF and (C) intravenous insulin injection. Intragastric volume was recorded with a barostat set at a constant preselected pressure level (MDP + 2 mm Hg). Pancreatic polypeptide (PP) secretion was measured as an indicator of cholinergic tone. RESULTS: PP secretion increased significantly after both MSF (p<0.05) and insulin administration (p<0.01). No changes in intragastric volume were seen after MSF, while intragastric volume increased significantly in response to insulin-induced hypoglycemia when compared to control (290+/-43 vs. 148+/-24 ml; p<0.01). No differences in perception scores were seen between the three experiments. CONCLUSIONS: Vagal cholinergic stimulation by MSF has no effect on the motor function of the proximal stomach, while insulin-induced hypoglycemia causes a relaxation of the proximal stomach.

Adult↗

PubMed1996

Ocular abnormalities in congenital cytomegalovirus infection.

BACKGROUND: Congenital cytomegalovirus (CMV) infection often results in damage to the brain, auditory system and visual system that leads to debility. This report describes the frequency, severity and effect on vision function of ocular abnormalities in a large cohort of children with congenital CMV infection. METHODS: Serial eye examinations were performed on 445 infants and children with congenital CMV infection from one month to 9 years of age, assessing anatomic integrity, motor sensory function, retina and posterior pole. RESULTS: Ocular disease was manifest principally by chorioretinitis, optic atrophy, pigmentary retinopathy and strabismus; each of these findings occurred more frequently (p < 0.05) among children who were symptomatic at birth than among those who were initially asymptomatic. These same findings were also more common among patients born after a primary maternal infection than among those born after a recurrent maternal infection. More than half of the patients with symptomatic congenital CMV infection with chorioretinitis or optic atrophy had significant binocular vision impairment. CONCLUSIONS: Ocular disease is an important sequela of congenital CMV infection that can lead to impaired vision. In order to allow for early intervention, patients with congenital CMV infection should have eye examinations beginning in early infancy.

Alabama↗

PubMed2006

Correlation between parameters of electrophysiological, histomorphometric and sciatic functional index evaluations after rat sciatic nerve repair.

The rat sciatic nerve is a well-established model for the study of recovery from peripheral nerve injuries. Traditional methods of assessing nerve regeneration after nerve injury and repair, such as electrophysiology and histomorphometry, despite widely used in neural regeneration experiments, do not necessarily correlate with return of motor and sensory functions. The aim of this experimental study is to investigate the possible correlation between several parameters of peripheral nerve regeneration after repair of sectioned sciatic nerve in Wistar rat. A two-stage approach was used to obtain 17 parameters after electrophysiological, morphometric and sciatic functional index evaluations. Pearson's correlation analysis was performed between these results. Only two positives correlations between different classes of peripheral nerve assessments were noted, between sciatic functional index and proximal nerve fiber diameter (r=0.56, p<0.01) and between sciatic functional index and distal fiber diameter (r=0.50, p<0.01). The data presented in our study demonstrates that there is a poor correlation between the sciatic functional index and outcome measures of electrophysiological and morphometric evaluations.

Animals↗

PubMed2005

Chondroitinase ABCI improves locomotion and bladder function following contusion injury of the rat spinal cord.

Chondroitin sulfate proteoglycans are synthesized and deposited in the spinal cord following injury. These proteoglycans may restrict regeneration and plasticity and contribute to the limited recovery seen after an injury. Chondroitinase, a bacterial enzyme that catalyzes the hydrolysis of the chondroitin chains on proteoglycans, has been shown to improve motor and sensory function following partial transection lesions of the spinal cord. To assess the effects of chondroitinase in a clinically relevant model of spinal cord injury, 128 female Long-Evans rats received either a severe, moderate, or mild contusion injury at the vertebral level T9/T10 with a forceps model and were treated for 2 weeks with chondroitinase ABCI at 0.06 Units per dose, penicillinase, or vehicle control via an intrathecal catheter placed near the injury. Motor behavior was measured by open-field testing of locomotion and bladder function monitored by measuring daily residual urine volumes. Animals treated with chondroitinase showed significant improvements in open-field locomotor activity as measured by the Basso, Beattie and Bresnahan scoring system after both severe and moderate SCI (p<0.05 and 0.01, respectively). No significant locomotor differences were observed in the mild injury group. In the moderate injury group, residual urine volumes were reduced with chondroitinase treatment by 2 weeks after injury (p<0.05) and in the severe injury group, by 6 weeks after injury (NS). These results demonstrate that chondroitinase is effective at promoting both somatic and autonomic motor recovery following a clinically relevant contusion spinal cord injury and is a candidate as a therapeutic for human spinal cord injury.

Animals↗

PubMed1986

Structure and function of specialized cilia in the exocrine pancreas.

Cilia are found in acinar and ductular lumina. Most descriptions of human or dog pancreatic tissue have indicated that these are probably motile structures which move and/or mix pancreatic secretion. A recent study interpreted arrangements of microtubules within cilia which deviated from the classic 9 + 2 pattern as indicating pathological change. There have been suggestions, however, from studies on nonmammalian and human pancreas, that the structure of pancreatic cilia suggests a sensory function. The present paper reports studies on the ultrastructural organization of the specialized cilia in human and canine pancreatic tissue. The pattern of microtubular organization resembles that of cilia modified for chemoreception rather than that of classic kinocilia. It is concluded that pancreatic ductular cilia are sensory rather than motile, providing a mechanism for monitoring general or specific molecular concentrations.

Animals↗

PubMed1996

Activity levels and cognitive functioning in an elderly community sample.

The influence of self-reported and informant-reported activity levels on Crystallized Intelligence, Fluid Intelligence, Memory and the Mini-Mental State Examination was investigated in a sample of 858 community-dwelling elderly subjects. Both self-reported and informant-reported activity levels explained variance beyond that accounted for by sex, sensory functioning, activities of daily living, medical conditions, current health problems and education. Age accounted for additional variance once activity and the other contextual variables were entered. Interaction effects indicated that inactivity was associated with poorer performance on fluid intelligence in older rather than younger elderly subjects and that inactivity was predictive of poor crystallized intelligence at younger ages. Higher informant-rated activity levels moderated the effects of education, so that higher activity offset effects associated with low education on memory tasks. The mount of variance explained by activity levels was modest.

Activities of Daily Living↗

PubMed1996

Total anorectal reconstruction results in complete anorectal sensory loss.

Six patients underwent objective measurement of anorectal sensory function following abdominoperineal excision of the rectum and total anorectal reconstruction. No patient perceived neorectal distension as a desire to defaecate or as a feeling of flatus. Anal mucosal sensation was preserved in two patients in whom some anal mucosa was retained. These sensory deficiencies may result in faecal retention and incontinence in patients undergoing reconstructive surgery. The loss of rectal sensation suggests that the prime sensors of rectal filling may lie within the rectum itself.

Aged↗

PubMed1988

Reorganization of primary afferent nerve terminals in the spinal dorsal horn of the primate caudal to anterolateral chordotomy.

A primate model has been used to explore the possibility that anterolateral chordotomy may produce intraspinal sprouting or rearrangement of primary afferent nerve terminations that could account for delayed postoperative recovery of sensory function. Monkeys were trained to limit the duration of an electrical stimulus, and the vigor and frequency of their escape responses were used to differentiate painful from nonpainful levels of stimulation. Behavioral testing after chordotomy revealed: 1) contralateral hypalgesia in all animals, with sensory recovery in half of the group, and 2) bilateral decreases in reflexive force in all animals, with reflex recovery in the majority of monkeys. At the terminal experiment, dorsal rootlets caudal to the spinal lesion were labeled bilaterally with HRP, and the distribution of labeled synaptic complexes was determined within the dorsal horn. When compared to controls, animals undergoing chordotomy showed a loss of terminals in the superficial dorsal horn and an increase of synaptic enlargements in deeper layers. These effects were bilateral, but were most pronounced on the side contralateral to chordotomy. Animals with diffuse spinal lesions showed a completely different change in the distribution of primary afferent terminals. Animals with sensory recovery demonstrated a more normal terminal distribution pattern than persistently hypalgesic monkeys, but there was considerable variability in the data, and analysis by different statistical tests yielded varying results.

Afferent Pathways↗

PubMed1975

[Correlation between sensory action potentials and vibratory perception in uremic polyneuropathy (author's transl)].

1. The sensory action potentials of the tibial nerve at the medial malleolus were studied by averaging in 51 patients with chronic renal failure treated by hemodialysis. Vibratory sense was also tested quantitatively on the dorsum of the foot with a pallesthesiometer. 2. Good correlation was found between sensory tibial nerve potentials and vibration sense in subclinical as well as in clinical uremic polyneuropathy. A biphasic potential correlated with unaffected vibration sense in 18 out of 23 patients, and impaired vibratory sense with a polyphasic response in 20 of 28 patients. Maximal nerve conduction of sensory fibres was faster (mean 37.4 m/sec) in cases with normal vibratory sense, but slower (mean 31.3 m/sec), when vibratory sense was impaired. Furthermore there was a correlation between the threshold of vibratory perception and sensory nerve conduction. 3. Sensory function, tested with conventional methods, was impaired only 5 times in 28 patients with altered vibratory perception. 4. The earlier impairment, especially of the vibratory sense, may be explained by the following neurophysiological mechanisms: a) Because of the polyphasic prolonged response of the sensory potentials, no rhythmical groups of impulses reach the central nervous system, but only a continual stream of small peaks arrives, so that vibration perception does not develop. b) A multiplication of the frequency of discharges caused by alternating firing of different sensory fibres is impossible due to the reduction of the number of axons. c) The prolongation of the relatively refractory period due to demyelinization of the surviving fibres prevents the transmission of frequent impulses. 5. Alterations of the sensory action potentials of the tibial nerve, as well as of vibratory perception tested quantitatively, are earlier signs of uremic polyneuropathy than the prolonged motor nerve conduction velocity. Since not all patients give accurate information when tests of vibratory sense are performed both methods should be applied. Physiological polyphasia of sensory action potentials and diminishing vibration perception in advanced age must be taken into account.

Action Potentials↗

PubMed1998

Experimentation with a transcranial magnetic stimulation system for functional brain mapping.

We describe functional brain mapping experiments using a transcranial magnetic stimulation (TMS) device. This device, when placed on a subject's scalp, stimulates the underlying neurons by generating focused magnetic field pulses. A brain mapping is then generated by measuring responses of different motor and sensory functions to this stimulation. The key process in generating this mapping is the association of the 3-D positions and orientations of the TMS probe on the scalp to a 3-D brain reconstruction such as is feasible with a magnetic resonance image (MRI). We have developed a registration system which not only generates functional brain maps using such a device, but also provides real-time feedback to guide the technician in placing the probe at appropriate points on the head to achieve the desired map resolution. Functional areas we have mapped are the motor and visual cortex. Validation experiments focus on repeatability tests for mapping the same subjects several times. Applications of the technique include neuroanatomy research, surgical planning and guidance, treatment and disease monitoring, and therapeutic procedures.

Brain Mapping↗

PubMed2004

Magnetic brain stimulation can improve clinical outcome in incomplete spinal cord injured patients.

STUDY DESIGN: Preliminary longitudinal clinical trial. OBJECTIVES: To test the efficacy of repetitive transcranial magnetic stimulation (rTMS) in modulating corticospinal inhibition and improving recovery in stable incomplete spinal cord injury (iSCI). SETTING: National Spinal Injuries Centre, Stoke Mandeville Hospital, Bucks, UK and Division of Neuroscience, Imperial College Faculty of Medicine, Charing Cross Hospital, London, UK. METHODS: Four stable iSCI patients were treated with rTMS over the occipital cortex (sham treatment) and then over the motor cortex (real treatment). Patients were assessed using electrophysiological, clinical and functional measures before treatment, during sham treatment, during the therapeutic treatment and during a 3-week follow-up period. RESULTS: Cortical inhibition was reduced during the treatment week. Perceptual threshold to electrical stimulation of the skin, ASIA clinical measures of motor and sensory function and time to complete a peg-board improved and remained improved into the follow-up period. CONCLUSION: In this preliminary trial, rTMS has been shown to alter cortical inhibition in iSCI and improve the clinical and functional outcome. SPONSORSHIP: This work was supported by the International Spinal Research Trust.

Adult↗

PubMed1998

Neural interfaces for regenerated nerve stimulation and recording.

A class of implantable, regeneration-type neural interfaces (NI's) for mammalian peripheral nerve recording and stimulation were developed using different fabrication processes and integrating purposely designed components. A typical NI comprises three main components: 1) a microfabricated silicon die incorporating a microelectrode array on multiple through-holes, 2) a polymer guidance channel housing the die, and 3) a flexible flat cable connecting the die to an external electronic circuitry. The design and fabrication of the NI's were aimed at achieving long term, reliable implants by taking into careful account the biological, electrical, and mechanical requirements of the specific implant site. Different versions of the NI were fabricated and implanted between the severed ends of the sciatic nerve in a mammalian animal model (rabbit). Morphological and histological evidence showed that nerves regenerated through the NI's and electrophysiological results demonstrated the recovery of electrical functionality. Moreover, the NI's allowed stimulation of the regenerated nerve producing a visible leg/foot contraction. The NI's presented in this paper are being further improved in the authors' laboratories with the ultimate goal of allowing the control of nerve motor and sensory functions in future prosthetic devices.

Action Potentials↗

PubMed2002

Effects of the duration of early strabismus on the binocular responses of neurons in the monkey visual cortex (V1).

PURPOSE: To determine how the duration of early strabismus influences the severity of loss of disparity sensitivity in V1 neurons and the effects of extensive poststrabismus visual experience on the maintenance of functional binocular connections. METHODS: Concomitant strabismus was optically simulated in 10 rhesus monkeys using a prism-rearing procedure. The onset of strabismus was kept constant at 4 weeks of age and the duration was maintained for 2, 4, or 8 weeks. In one group of monkeys (infants), the neurophysiological experiments were conducted immediately after the period of rearing with prisms. In another group (adults), after the termination of the prism-rearing regimen at either 8 or 12 weeks of age, the monkeys were kept in a normal housing environment until maturity and behavioral testing was conducted before the recording experiments to determine the animal's monocular and binocular visual capacities. To assess the effects of the period of early strabismus on binocular interactions in V1, extracellular single-unit recording methods were used in anesthetized and paralyzed monkeys, and dichoptic sine-wave gratings were used as stimuli. RESULTS: In all strabismic monkeys, the sensitivity of V1 units to interocular spatial phase disparity (disparity sensitivity) was significantly reduced, and the prevalence of binocular suppression was higher than that found in age-matched control animals. Although 8 weeks of strabismus resulted in a slightly larger loss of disparity sensitivity, the overall effects of the duration of strabismus were surprisingly small in infant strabismic monkeys. After poststrabismus visual experience, a small but significantly higher degree of disparity sensitivity was noted in V1 if prism-rearing was terminated after 4 weeks of strabismus (i.e., at 8 weeks of age), but not after 8 weeks of strabismus (i.e., at 12 weeks of age). CONCLUSIONS: A brief period (2 weeks) of misalignment after the emergence of stereopsis is sufficient to drastically reduce the functional binocular connections in V1, and longer periods of strabismus result in little additional loss in disparity sensitivity. Clinically, these results suggest that taking corrective measures for infantile esotropes before the known onset age for stereopsis may be important for maintaining better binocular sensory function and better interocular alignment at later stages of development.

Aging↗

PubMed1982

The radiology of pulmonary complications associated with acute spinal cord injury.

Pulmonary complications after acute cervical spinal cord injury are common. Paralysis of the intercostal muscles leads to decreased respiratory function. In addition, injuries of the thoracic cage, pleura and lungs are commonly associated with spinal injuries. A survey of radiologically demonstrable pulmonary complications in 50 patients with acute tetraplegia has been made. Changes were present in 28% of the patients surveyed. The changes in pulmonary and haemodynamic function consequent upon cervical spinal cord injury are briefly described. Radiological manifestations of pulmonary complications due to decreased pulmonary function, direct pulmonary trauma and rare pulmonary complications of skeletal injury are reviewed. The value of routine and intensive radiographic monitoring of the chest in the patient with acute tetraplegia is emphasized, as clinical diagnosis is hampered in the absence of motor and sensory function.

Acute Disease↗