SEARCH · PubMed Health

Results for “sensory function”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 991 records · Page 55Linked to original sources

PubMedDate not supplied

Psychophysical testing in human populations exposed to neurotoxicants.

Sensory organs can be studied from different points of view: biochemical, morphological, electrophysiological, clinical, and psychophysical. In this paper, the psychophysical and electrophysiological approaches are discussed and compared. Even though close parallels have been drawn between these two methodologies, discrepancies clearly indicate that they do not measure the same phenomenon. Vibration sensitivity is used to illustrate the role sensory assessment plays in neurotoxicology. Several psychophysical techniques are described to measure this sensory modality. Emphasis is placed on the need to quantitatively define stimulus parameters. The validity of vibration sensitivity as an indicator of sensory peripheral nerve dysfunction is established through a review of diseases, physical agents, pharmaceuticals, and other neurotoxicants known to alter the morphology and/or the physiology of the peripheral nervous system or sense organs. A series of factors or conditions affecting vibration detection thresholds, such as age, laterality, gender, temperature and others, are examined. Finally, a review of the psychophysical methods and procedures illustrates the advantages of the forced-choice paradigm and the tracking technique over other procedures and methods of stimulus presentation. The importance of psychophysical assessment of sensory functions in neurotoxicology is emphasized.

Electrodiagnosis↗

PubMed1990

Direct parameter specification and the concept of perception.

Stimuli that reach the sensory surface may result in perception, or serve to guide action. How are these two potential consequences of sensory stimulation related? I discuss three aspects of this problem. The conceptual aspect concerns the status of the concept of perception in an objective psychology. The methodological aspect pertains to the problem of how psychophysics is related to the assessment of performance measures. The functional aspect relates to the function(s) of perception for action control. I argue that (a) conceptually, the term perception belongs to a different level of description than the constructs of information-processing models: (b) methodologically, psychophysical judgements and performance measures are not necessarily converging operations: (c) functionally, sensory information can be used for the control of action without perception as a mediating stage (direct parameter specification). Taken together, this suggests that perception should be conceptualized not as a processing stage, but as a class of actions that serve to establish and update an internal representation of the environment.

Attention↗

PubMed2002

Persistent paraplegia after an aqueous 7.5% phenol solution to the anterior motor root for intercostal neurolysis: a case report.

A 55-year-old white man with severe scoliosis and chest deformity was scheduled for an intercostal neurolysis for pain relief with 7.5% aqueous phenol solution. A 20 G needle was inserted 3 to 4cm lateral to the midline of the spine under the 10th right rib. After negative aspiration for blood and alcohol, 6mL of a 7.5% aqueous phenol solution was injected. Within a minute after the injection, the patient felt a warm sensation in his right leg, followed by loss of leg motor and sensory function on both sides. A lumbar puncture done 3.5 hours after the block showed a phenol concentration of 87.5 microg/mL. The most likely explanation is a diffusion of the phenol through the intervertebral foraminae reaching the spinal space and therefore damaging the motor and sensory roots. This case highlights the danger associated with phenol application in the vicinity of the spinal cord.

Humans↗

PubMed2001

Variations of concentric hair cells in a Cnidarian sensory epithelium (Coryne tubulosa).

In capitate hydropolyps, the spherical end-knobs of the short tentacles present an exceptional concentration of sensory functions in one of the evolutionarily oldest nervous systems. The tentacular spheres are the basis of sensation and discrimination of objects and of capturing of prey-objects by the discharge of nematocytes (stinging cells). Recent electrophysiological studies of the spheres revealed combined chemo/mechanosensory functioning of the nematocytes and mechanosensitivity of further types of cells. The present electron microscopical study made use of the small size of the spheres of Coryne tubulosa to characterize all cells of some spheres. Five types of ectodermal cells were found to have sensory structural features and to be separated by or enclosed in supporting cells: 1) nematocytes of the stenotele type; 2) short and 3) long ciliated concentric hair cells, which carry a cilium-stereovilli bundle, similar to the cnidocil apparatus of nematocytes; 4) cells having a recessed cilium-microvilli complex equipped with a thick cell-traversing rootlet (rootlet cells); and 5) cells having a recessed short cilium with no microvilli and only a short rootlet and containing, apically as well as basally, aggregations of dense-core vesicles (vesicle-rich cells). Types 1-4 vary the configuration of a concentric cilium-microvilli complex (variations of a concentric hair bundle) and were demonstrated or inferred to be mechanosensitive. Apical exocytotic activity, which is well known for the nematocytes (discharge of their cnidocyst), is indicated by ultrastructure for the nematocyte-resembling concentric hair cells and for the vesicle-rich cells. The tentacular spheres are considered an early paradigm of a sensory epithelium. Its synaptic structures and extensive connectivity are the subject of a subsequent paper.

Animals↗

PubMed1998

Normal distributions of thermal and vibration sensory thresholds.

The distributions of sensory thresholds were estimated in a healthy population while controlling for potential covariates. Using the method of levels and the two-alternative forced choice, thermal and vibration thresholds respectively were measured in the hand and foot of 148 subjects. Age was uniformly distributed between 20 and 86 years. Independent effects of age, gender, height, and skin temperature were estimated using multiple linear regression. Parametric and nonparametric methods were used to estimate the distributions of interest. Significant age-related increases were observed for all vibration thresholds (P < 0.0001), and for thermal thresholds in the foot (P < 0.0002). Percentiles were estimated for thermal thresholds in the hand and age-adjusted continuous distributions were calculated for all other thresholds. Height was positively associated with vibration thresholds in the foot (P < 0.003), and appropriate corrections were made. Our results provide reference values for thermal and vibration sensory thresholds in a healthy population, allowing for the accurate diagnosis of disordered sensory function.

Adult↗

PubMed2005

Identification of the sites of expression of triple A syndrome mRNA in the rat using in situ hybridisation.

Triple A syndrome is characterised by achalasia, alacrima, adrenocorticotropin-resistant adrenal insufficiency and a variable and progressive neurological phenotype. It is caused by mutations in a gene that is normally referred to as the triple A syndrome gene (AAAS) and which has recently been shown to encode a nuclear pore protein named ALADIN (alacrima, achalasia, adrenal insufficiency neurologic disorder). In this study we performed in situ hybridisation with radioactive oligonucleotide probes in the adult and developing rat and present the first detailed map of AAAS mRNA expression. Consistent with a role for AAAS in adrenal function, we detected high levels of its mRNA in the adrenal cortex. On the other hand hepatocytes, enteric smooth muscle and fibroblasts had relatively little or no detectable AAAS mRNA. In both the peripheral and central nervous systems, AAAS mRNA was abundantly expressed. Neurons in sensory and sympathetic ganglia expressed high levels. CNS expression was highest in neurons of the cerebral cortex, cerebellum, hippocampus, motor-associated nuclei of the brainstem including cranial nerve nuclei, and ventral horn of the spinal cord. Although neuronal expression of AAAS mRNA was striking, non-neuronal cells including those of the circumventricular organs and fibrous astrocytes also expressed AAAS mRNA. Within the developing embryo, the highest levels of expression were found in neural tissues. These findings indicate a widespread but not ubiquitous or uniform expression of AAAS mRNA in the rat. Robust expression in neural systems associated with cognitive, motor and sensory functions is consistent with the myriad of symptoms experienced by patients with triple A syndrome.

Animals↗

PubMed2003

Severe cognitive and motor coordination deficits in tenascin-R-deficient mice.

The extracellular matrix molecule tenascin-R (TN-R), predominantly expressed in the central nervous system, has been implied in a variety of functions, e.g. during myelination, cerebellar neurite fasciculation and hippocampal long-term potentiation. In this study, we investigated in detail the impact of TN-R deficiency on the living animal by analyzing the behavior of TN-R-deficient mice. The general state, gross sensory functions, reflexes and motoric capabilities appeared normal. In contrast, motor coordination on the rota-rod was compromised in these mice, indicating a deficit in cerebellar functions. In the open field and the hole board, the mutants interact differently with their environment, probably due to differences in their exploratory behavior. TN-R-deficient mice were able to learn a reference memory task in the Morris water maze. In contrast to wild-type mice, the mutants displayed an alternative strategy; swimming around the pool using a stereotypical circling pattern, crossing all possible platform positions after relocation of the escape platform (reversal). These results, confirmed by relocating the platform in the center of the pool, suggest that TN-R-deficient mice may be impaired in constructing a goal-independent representation of space. In addition, a two-way active avoidance test (shuttle box) revealed a severe deficit in associative learning in TN-R-deficient mice. Our results support important functions of TN-R in vivo in the central nervous system, in particular in the cerebellum and the hippocampus.

Animals↗

PubMed1994

Facial sensibility in adolescents with and without clefts 1 year after undergoing Le Fort I osteotomy.

Static two-point discrimination, pressure, and vibratory threshold values were measured at standard coordinates in the area corresponding to the infraorbital nerve distribution in 59 adolescents 1 year after undergoing LeFort I osteotomy. The patients were divided into three groups: those born with unilateral cleft lip and palate (n = 30; mean age, 18 years; SD = 2); those with bilateral cleft lip and palate (n = 12; mean age, 19 years; SD = 3); and those without a cleft (n = 17; mean age, 19 years; SD = 3). One year after the osteotomy, none of the patients complained of altered sensibility in the maxillary vestibular mucosa, gingiva, or upper lip and cheek regions. No significant differences were found between the mean postoperative sensibility values of patients with and without clefts, indicating that the presence of clefting did not affect sensory recovery. Mean postoperative static two-point discrimination values were higher than preoperative values in all areas tested and in all patient groups. These results suggest that the sensory recovery, although incomplete, was strong enough to mask any subjective feelings of changes in sensory function.

Adolescent↗

PubMed2006

Stimulation of the posterior cord predicts successful infraclavicular block.

Infraclavicular (IC) block is often performed by localizing one cord within the brachial plexus sheath and placing all the local anesthetic solution at that location. We hypothesized that posterior cord stimulation would be associated with a greater likelihood of IC block success. We enrolled 369 patients scheduled for surgery to the lower arm or hand in a prospective, nonrandomized observational trial. All underwent IC blocks using a standard technique, and the cord stimulated immediately before drug injection was recorded. Motor and sensory functioning were evaluated 15 min after injection. Compared with stimulation of either the lateral or medial cord, stimulation of the posterior cord was associated with rapid onset of motor block in significantly more nerves, as well as a decreased likelihood of block failure (motor and sensory block inadequate to perform surgery). Failure rates were 5.8% for posterior cord, 28.3% for lateral (P < 0.05), and 15.4% for medial (P < 0.05). The differences were highly significant when adjusted for multiple possible confounders, such as gender, body mass index, location of the incision, and level of training of the individual performing the block (P < 0.001, lateral versus posterior; P = 0.003, medial versus posterior). A low failure rate was also predicted by stimulation of more than one cord simultaneously (P < 0.05). We conclude that injection after locating the posterior cord or multiple cords predicts successful IC block.

Adult↗

PubMed1983

A new technique for the assessment and modification of feigned memory deficit.

The two-alternative forced-choice technique has been successful in the assessment of functional sensory deficits because it has the power to assess deception or exaggeration. This report describes how the procedure can be used for the assessment and modification of a memory complaint. Three case studies are presented. In two cases the supposed deficit was judged to be functional. In a third case a brain-injured patient "cheated" to obtain correct answers, suggesting that he was trying to hide a deficit and not attempting to obtain compensation.

Adult↗

PubMed1997

Function and organization in dysgenic cortex. Case report.

Cerebral dysgenesis is a subject of interest because of its relationship to cerebral development and dysfunction and to epilepsy. The authors present a detailed study of a 16-year-old boy who underwent surgery for a severe seizure disorder. This patient had dysgenesis of the right hemisphere, which was composed of a giant central frontoparietal nodular gray matter heterotopia with overlying large islands of cortical dysplasia around a displaced central fissure. Exceptional insight into the function, biochemistry, electrophysiology, and histological structure of this lesion was obtained from neurological studies that revealed complementary information: magnetic resonance (MR) imaging, [18]fluoro-2-deoxy-D-glucose positron emission tomography (PET), functional PET scanning, proton MR spectroscopic (1H-MRS) imaging, intraoperative cortical mapping and electrocorticography, in vitro electrophysiology, and immunocytochemistry. These studies demonstrated compensatory cortical reorganization and showed that large areas of heterotopia and cortical dysplasia in the central area may retain normal motor and sensory function despite strikingly altered cytoarchitectonic organization and neuronal metabolism. Such lesions necessitate appropriate functional imaging studies prior to surgery and cortical mapping to avoid creating neurological deficits. Integrated studies, such as PET, 1H-MRS imaging, cortical mapping, immunocytochemistry, and electrophysiology may provide information on the function of developmental disorders of cerebral organization.

Adolescent↗

PubMed1984

Measurement of the global and functional dimensions of health status in the elderly.

Data from a two-stage random sample of 401 noninstitutionalized elderly individuals residing in 18 census tracts in south-central metropolitan St. Louis were used to examine the relationships among seven measures of health status. Factor analyses revealed two pristine dimensions: (a) a global health status dimension, on which perceived health status, nutritional risk, perceived sensory functions, and mental health all load significantly; and, (b) a functional dimension on which the Activities of Daily Living, Instrumental Activities of Daily Living, and mental orientation measures all load significantly. These two factors explain 56% of the variance in the seven health status measures, and, using an oblique rotational procedure, they were found to be correlated only modestly (r = .37). The implications for the measurement of health status of elderly adults as well as the use of such measures in predicting health services utilization are discussed, and recommendations for the inclusion of items tapping both dimensions in future studies are presented.

Activities of Daily Living↗

PubMed1994

Persistent sacral sensory deficit induced by intrathecal local anesthetic infusion in the rat.

BACKGROUND: Several cases of cauda equina syndrome after continuous spinal anesthesia have been recently reported. One possible etiology is toxic exposure of the sacral roots resulting from intrathecal maldistribution of a relatively large dose of local anesthetic. The current experiments sought to determine whether a local anesthetic solution, injected intrathecally to produce a restricted distribution of anesthesia, could result in a sacral deficit. In addition, we sought to test the hypothesis that, when equal volumes are administered intrathecally, significant differences exist in the potential to three commonly used anesthetic solutions to induce sensory impairment. METHODS: Thirty-two rats were implanted with intrathecal catheters to permit repetitive infusion of local anesthetic. Animals were randomly assigned to four groups of eight to receive either 5% lidocaine with 7.5% dextrose; 0.75% bupivacaine with 8.25% dextrose; 0.5% tetracaine with 5% dextrose; or normal saline. Each rat received, in sequence, a 1-h (60 microliters), a 2-h (120 microliters), and a 4-h (240 microliters) infusion; the infusions were separated by a 4-day rest period. Sensory function was assessed using the tail-flick test, which was performed immediately before each infusion and 6 days after the last infusion by an investigator blinded to the solution infused. RESULTS: There was no significant difference in baseline tail-flick latencies for the four groups. Tail-flick latency for the lidocaine group was significantly prolonged when compared with the bupivacaine, tetracaine, and saline groups. This difference was apparent after the first infusion and persisted throughout the study. CONCLUSIONS: In the rat, restricted anesthetic distribution can be achieved, and sensory impairment may result. These findings further support an etiology of local anesthetic neurotoxicity for recent clinical injuries after continuous spinal anesthesia. The functional model described appears to be suitable for in vivo study of local anesthetic neurotoxicity.

Anesthesia, Local↗

PubMed1998

Nitric oxide in invertebrates.

Nitric oxide (NO) is considered an important signaling molecule implied in different physiological processes, including nervous transmission, vascular regulation, immune defense, and in the pathogenesis of several diseases. The presence of NO is well demonstrated in all vertebrates. The recent data on the presence and roles of NO in the main invertebrate groups are reviewed here, showing the widespread diffusion of this signaling molecule throughout the animal kingdom, from higher invertebrates down to coelenterates and even to prokaryotic cells. In invertebrates, the main functional roles described for mammals have been demonstrated, whereas experimental evidence suggests the presence of new NOS isoforms different from those known for higher organisms. Noteworthy is the early appearance of NO throughout evolution and striking is the role played by the nitrergic pathway in the sensorial functions, from coelenterates up to mammals, mainly in olfactory-like systems. All literature data here reported suggest that future research on the biological roles of early signaling molecules in lower living forms could be important for the understanding of the nervous-system evolution.

Animals↗

PubMed1996

Brown-Séquard and his syndrome.

The contributions of Charles Edouard Brown-Séquard (1817-1894) to the advancement of medical science included his emphasis on functional processes in the integrative action of the nervous system, his discovery of the vasomotor nerves, his experimental demonstration that the adrenal glands are esential to life, and his pioneering work on hormone replacement therapy. He is best remembered, however, for his work in delineating the sensory pathways in the spinal cord. His later work on the sensory function of the cord emphasized dynamic spinal mechanisms that may well have major implications for the rehabilitation of patients with cord injuries.

History, 19th Century↗

PubMed2006

Irritable bowel syndrome: recent and novel therapeutic approaches.

Irritable bowel syndrome (IBS) is a highly prevalent functional gastrointestinal disorder affecting up to 3-15% of the general population in Western countries. It is characterised by unexplained abdominal pain, discomfort and bloating in association with altered bowel habits. The pathophysiology of IBS is considered to be multifactorial, involving disturbances of the brain-gut-axis: IBS has been associated with abnormal gastrointestinal motor functions, visceral hypersensitivity, psychosocial factors, autonomic dysfunction and mucosal inflammation. Traditional IBS therapy is mainly symptom oriented and often unsatisfactory. Hence, there is a need for new treatment strategies. Increasing knowledge of brain-gut physiology, mechanisms, and neurotransmitters and receptors involved in gastrointestinal motor and sensory function have led to the development of several new therapeutic approaches. This article provides a systematic overview of recently approved or novel medications that show promise for the treatment of IBS; classification is based on the physiological systems targeted by the medication. The article includes agents acting on the serotonin receptor or serotonin transporter system, novel selective anticholinergics, alpha-adrenergic agonists, opioid agents, cholecystokinin antagonists, neurokinin antagonists, somatostatin receptor agonists, neurotrophin-3, corticotropin releasing factor antagonists, chloride channel activators, guanylate cyclase-c agonists, melatonin and atypical benzodiazepines. Finally, the role of probiotics and antibacterials in the treatment of IBS is summarised.

Animals↗

PubMed2003

Effect of short-term and long-term antioxidant therapy on primary and secondary ageing neurovascular processes.

Previous studies from our laboratory demonstrated an age-related functional decline in sensory neurones and their modulation of microvascular blood flow (primary ageing processes) that correlated with a deficiency in tissue repair (a secondary ageing process). We also raised the notion of a possible role for free radicals in these age-related changes. The aim of this study was to investigate the impact of antioxidant therapy on modulating sensory neurovascular function and tissue repair with age. Twenty-four-month-old Sprague-Dawley rats were treated with vitamin E for short-term (40 mg/kg, i.p., every other day for 2 weeks) or long-term (for 12 months in advance, 10 g/kg, incorporated in food). These treated rats were assessed for the effectiveness of treatment and tested for their sensory neurovascular function, repair of full-thickness burn, and recovery from hyperalgesia following nerve injury. The results indicate that both short- and long-term vitamin E treatments are effective in improving sensory neurovascular function and in reducing the time required for complete wound closure of full-thickness burn injury. Short-term vitamin E treatment was more effective in protecting against the development of hyperalgesia following nerve injury. An initial increase in wound size and in hyperalgesia was observed in the treated animals, and could reflect possible side effects of the antioxidant therapy and support the importance of free radicals in early stages of the repair process. The data, overall, support the notion that oxidative damage contributes to both primary and secondary ageing processes.

Aging↗

PubMed2003

Functional assessment of sciatic nerve recovery: biodegradable poly (DLLA-epsilon-CL) nerve guide filled with fresh skeletal muscle.

The aim of this study was to compare functional peripheral nerve recovery in the rat sciatic nerve model after reconstruction of a 10-mm gap with a biodegradable poly (DLLA-epsilon-CL) nerve guide, as filled with either fresh skeletal muscle or phosphate-buffered saline (PBS). During 24 weeks of recovery, motor and sensory functional evaluation was tested by extensor postural thrust (EPT) and withdrawal reflex latency (WRL), respectively. At the end of the experiment, anesthetized animals were prepared for motor nerve conduction velocity (MNCV) studies, followed by gastrocnemius and soleus muscle weight measurement. Motor functional recovery was greater in the muscle-grafted group, and reached a significant difference from weeks 8-12 (P < 0.05). The results of this investigation suggest that filling a nerve guide with fresh skeletal muscle induces faster maturation of regenerated nerve fibers in comparison with traditional tubular repair.

Absorbable Implants↗