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At least 937 records · Page 52Linked to original sources

PubMed1996

Tilt responses of neurons in the caudal descending nucleus of the decerebrate cat: influence of the caudal cerebellar vermis and of neck receptors.

1. In decerebrate cats with intact cerebellums, we studied the responses of neurons in the caudal areas of the vestibular nuclei to natural vestibular stimulation in vertical planes and to neck rotation. The activity of most neurons was recorded in the caudal half of the descending nucleus. 2. One goal of our experiments was to compare the dynamic and spatial properties of responses to sinusoidal vestibular stimulation with those seen in previous experiments in which the caudal cerebellar vermis, including the nodulus and uvula, was removed. This part of the cerebellum receives vestibular input and projects to the caudal areas of the vestibular nuclei, suggesting that it could influence responses to stimulation of the labyrinth. 3. As in our previous experiments, most neurons could be classified as receiving predominant input either from the otoliths or from one vertical semicircular canal. When mean gain and phase and response vector orientations were compared, there were no obvious differences between the behavior of neurons in the partially decerebellate preparation and the one with the cerebellum intact, demonstrating that in the decerebrate cat the nodulus and uvula have little or no influence on the processing of vertical vestibular input in this region of the vestibular nuclei. 4. Only 23 of 74 (31%) of neurons tested responded to neck rotation. This contrasts with the much larger fractions that respond to this stimulus in Deiters' nucleus and in the rostral descending nucleus. We also recorded from neurons near the vestibular nuclei, mainly in the external cuneate nucleus. All of them (9 of 9) responded to neck rotation. 5. Responses to neck rotation also differed in their dynamics from those found more rostrally in the vestibular nuclei. Dynamics of more rostral neurons resemble those of neck muscle spindles, as do those of external cuneate neurons. The dynamics of caudal vestibular neurons, on the other hand, have a steeper gain slope and more advanced phases than do those of neurons in the more rostral vestibular nuclei. This suggests the possibility of involvement of additional receptors in the production of these responses. 6. In the more rostral vestibular nuclei, responses to vestibular and neck rotation are most often antagonistic, so that head rotation results in little or no response. This is not the case in the caudal areas of the vestibular nuclei, where less than half the neurons tested displayed antagonistic behavior. Further experiments are required to put the neck projection to the caudal vestibular nuclei in a functional context.

Animals↗

PubMed1980

Crosses and uncrossed synaptic actions on motoneurones of back muscles in the cat.

Intracellular recording from motoneurones of back muscles was used to analyze their synaptic input. The sample included motoneurones located in Th13--L2 spinal segments, identified by their antidromic invasion following stimulation of medial, intermediate and lateral branches of the dorsal rami. The motoneurones were monosynaptically excited from lowest threshold ipsilateral afferents and from ipsilateral descending spinal tracts. Polysynaptic EPSPs and/or IPSPs were evoked in them from higher threshold ipsilateral and contralateral afferents and from descending spinal tracts, and recurrent inhibition was evoked from ipsilateral motor axon collaterals. There was no evidence of crossed disynaptic inhibition from group I afferents, or crossed recurrent inhibition of these neurones. Supplementary records from another group of neurones in Th13--L2 segments, unidentified but likely to innervate other back or abdominal muscles, showed monosynaptic and polysynaptic PSPs of the same origin, and in addition disynaptic IPSPs and disynaptic EPSPs from contralateral ventral roots. The crossed IPSPs had features of the crossed recurrent IPSPs, while the crossed EPSPs appeared to be more likely evoked by some afferents passing via the ventral roots. Generally, the input to the investigated neurones showed greatest similarities to the input to motoneurones of neck muscles and differed from that reported for tail motoneurones.

Afferent Pathways↗

PubMed2005

Role of endogenous serotonin in modulating genioglossus muscle activity in awake and sleeping rats.

RATIONALE: Exogenous serotonin at the hypoglossal motor nucleus (HMN) stimulates genioglossus (GG) muscle activity. However, whether endogenous serotonin contributes to GG activation across natural sleep-wake states has not been determined, but is relevant given that serotonergic neurons have decreased activity in sleep and project to pharyngeal motoneurons. OBJECTIVES: To determine the role of endogenous serotonin at the HMN in modulating GG activity across natural sleep-wake states. METHODS: Ten rats were implanted with electroencephalogram and neck muscle electrodes to record sleep-wake states, and GG and diaphragm wires for respiratory muscle recordings. Microdialysis probes were implanted into the HMN for perfusion of artificial cerebrospinal fluid and the serotonin receptor antagonist mianserin (100 microM). MEASUREMENTS AND MAIN RESULTS: In room air, there was no effect of mianserin on respiratory-related or tonic GG activities across sleep-wake states (p > 0.300). In hypercapnia, however, the normal declines in GG activity from non-REM to REM sleep, and wakefulness to REM sleep, were reduced with mianserin (p < 0.005). These data demonstrate a normally low endogenous serotonergic drive modulating GG activity unless augmented by reflex inputs. We also demonstrated a significant serotonergic drive modulating GG activity in vagotomized rats, but not in vagi-intact rats, under anesthesia, suggesting that previous results in reduced preparations may have been influenced by vagotomy. CONCLUSIONS: The results show a minimal endogenous serotonergic drive at the HMN modulating GG activity across sleep-wake states, unless augmented by reflex inputs. This result has implications for pharmacologic strategies aiming to increase GG activity by manipulating endogenous serotonin in patients with obstructive sleep apnea.

Animals↗

PubMed2005

[Paralyzed face. Ansa-cervicalis-nervi-hypoglossi].

INTRODUCTION: For 100 years hypoglossal-facial nerve anastomosis (HFA) has been a common surgical procedure for reanimation of paralyzed mimic muscles of the face after axotomy of the facial nerve. However, the denervation and subsequent scarred degeneration of the target muscles of the hypoglossal nerve often results in unfavorable late effects for speech and swallowing. Therefore, the ansa cervicalis nervi hypoglossi-facial nerve anastomosis (ACHFA) can be an alternative to avoid such late effects. As a branch of the hypoglossal nerve the ansa cervicalis innervates the infrahyoidal muscles. Neck dissection surgery proved that resection of the ansa cervicalis causes no side effects for swallowing because of several nerve anastomoses to the cervical plexus. PATIENTS AND METHOD: We compared our clinical results of eight cases following a delayed ACHFA with our own experiences after HFA and results from the literature. RESULTS: We found a reanimation rate lower than usually seen after HFA only in the target muscles of the forehead. This may be caused by a reduced neuronal plasticity of the ansa cervicalis. However, in the target muscles of the other two facial nerve branches we observed the same good results one would expect after HFA. There were no late side effects for swallowing and speech though.

Adult↗

PubMed1994

Does group gymnastics at the workplace help in neck pain? A controlled study.

The effects of group gymnastics on neck pain were studied among 44 women in a printing company. A randomized cross-over design was used with two groups matched according to the work task, frequency of symptoms, and age. The treatment consisted of gymnastics for 45 min once a week for 10 weeks. Neck pain was rated by visual analogue scale and pressure pain sensitivity of the neck muscles was measured with an algometer. The results showed no clear effects of the group gymnastics program. An equal and significant reduction in pain ratings was seen in both groups after the first intervention in the spring. Recurrence of symptoms was seen in both groups in September, and no significant reduction in pain occurred during the second intervention in the autumn. The results suggest a seasonal variation in neck symptoms which has to be considered when planning or evaluating intervention studies.

Adult↗

PubMed1993

Effectiveness of botulinum toxin in the treatment of spasmodic torticollis.

Thirty-two patients with spasmodic torticollis were assessed quantitatively for posture deformity, tremor and range of neck movement, and qualitatively for pain and global subjective disability. All patients were then treated with intramuscular botulinum toxin injections into appropriate neck muscles. Fifty-three treatments were administered using dosages of toxin in the range of 50-100 U per muscle. The maximum dose administered at a single sitting was 280 U. The progress of the patients was assessed during an 18-month period. Seventy-five percent of patients showed documented improvement in both subjective and objective parameters and were considered treatment successes. Pain improved in 65%, posture in 65%, tremor in 50% and range in 46%. The side effects that occurred were transient and included fatigue, dysphagia, neck weakness, hoarseness and local pain. This study demonstrates that treatment with botulinum toxin is of significant benefit for the majority of patients with spasmodic torticollis.

Adult↗

PubMed2004

Myasthenia Gravis.

Myasthenia gravis is a disorder of neuromuscular transmission, manifest by variable weakness of skeletal muscle. The disorder has a range of therapies that differ with respect to efficacy, timing, and side effects. The physician treating myasthenia gravis must be well versed in understanding the evidence basis for using these agents, as well as the trade-offs between persistent disease manifestations and their costs and expected benefits. Diagnosis of myasthenia gravis depends on recognizing the pattern of weakness, which typically involves some combination of extraocular, bulbar, facial, limb, and neck muscles. Management relies on some combination of medications that influence the function of the neuromuscular junction and treatments that alter the immune response. Thymectomy is commonly used, although trends in evidence-based medicine are leading expert clinicians to look closely at its efficacy. Plasma exchange is useful for patients in crisis, who require rapid improvement. The exact role for high-dose intravenous immunoglobulin in this setting is still being studied, although the agent is gaining popularity. Knowing that the treatments are effective is not enough. It is still important to determine the treatment that has a more rapid onset, because these patients often require intensive care or respiratory assistance.

Journal Article↗

PubMed1984

Opening and closing mechanisms of the larynx.

Opening and closing of the larynx are determined by the intrinsic and extrinsic muscles acting on the elastic forces in the tongue, pharynx, larynx, and trachea. The pharynx is opened or closed by two mechanisms: (1) Contractions of the cricothyroid and of the intrinsic muscles of the larynx open and close the vocal cords. (2) The false cords, ventricle, and true cords accordion open or close in a bellows mechanism. We conclude that the posterior cricoarytenoid opens the laryngeal airway. The cricothyroid together with the posterior cricoarytenoid accentuates this opening. The larynx is also opened by the geniohyoid, mylohyoid, sternothyroid, and middle constrictor. The thyrohyoid, cricothyroid, sternohyoid, and inferior constrictor close the laryngeal airway. Abnormalities in the soft tissues of the neck or of the innervation of the larynx, pharynx, and neck muscles may severely interfere with patency of the laryngeal airway. This occurs in such conditions as vocal cord paralysis, sleep apnea, multiple sclerosis, amyotrophic lateral sclerosis, spastic dysphonia, mandibular fractures or hypodevelopment, and cerebrovascular disease.

Animals↗

PubMed2003

Neck and abdominal muscle activity during a sniff.

Measurement of sniff nasal inspiratory pressure (SNIP) is now used widely as a simple, non-invasive assessment of global respiratory muscle strength, even though the technique evolved originally from measurements of trans-diaphragmatic pressure (Pdi) that reflect the status of the diaphragm. The relative participation of major respiratory muscles, apart from the diaphragm, in the generation of SNIP is not known. Therefore, we examined the activity during a sniff of both neck and abdominal "accessory" muscles. In seven young adults we implanted fine wire EMG electrodes under direct vision with high-resolution ultrasound into scalene, sternocleidomastoid, trapezius, and transversus abdominis. SNIP was measured during sniffs that were short and sharp, from low to maximal intensity, in both standing and supine postures. Mean maximum SNIP was -105.6cmH2O (SD 32.9) in supine and -94.5cmH2O (26.6) in the standing posture, (difference NS). In every subject, scalene activity appeared even at the lowest SNIP, and increased linearly with increasing SNIP. Sternomastoid activity appeared at higher SNIP levels in three of seven subjects. By contrast, trapezius activity was never present at low SNIP, and appeared in only 2 subjects at maximum SNIP. Sniff abdominal expiratory activity was inconsistent with no activity of transversus in four of seven subjects even at greatest SNIP. Thus, we observed differential activation among these non-diaphragm respiratory muscles during SNIP; while some accessory muscles were very active, others were unlikely to contribute to generation of SNIP. Clinically, this indicates SNIP will be impacted unequally by loss of function of specific respiratory muscles.

Abdominal Muscles↗

PubMed1995

[Tibial nerve and fibular nerve paresis in pigs after intramuscular injection in the caudal thigh muscle (case report)].

Paresis of the hindlimb in piglets after intramuscular injection of various therapeutics in the caudal thigh muscles were observed. The injection was followed by inflammatory changes of the muscle tissue at the injection site. The tibial and fibular nerve were enclosed in the alterations and showed a distinct to complete loss of nerve fibers resulting in clinical signs of paresis. The affected hindlimb was dragged on the dorsal digital surface. The piglet showed an extended consecutive swelling and ulceration below the hock and loss of the claws. These findings strongly demonstrate the necessity of a correct intramuscular injection in piglets, which should be done in the lateral neck muscles.

Animals↗

PubMed2005

Monitor position in laparoscopic surgery.

BACKGROUND: One of the key problems in laparoscopy is the ergonomic positioning of the monitor. In this study we tested task performance and muscle strain of subjects in relation to monitor position during laparoscopic surgery. METHODS: Eighteen subjects simulated laparoscopic suturing by threading tiny pearls with a curved needle. This was repeated in three monitor positions (15 min each): frontal at eye level (A), frontal in height of the operating field (B), and 45 degrees to the right side at eye level (C). Subjects were not allowed to turn their heads during these sessions. After the test they were asked for their preferred monitor position. During all tests the electromyographic (EMG) activity of the main neck muscles was recorded and the number of pearls was counted. RESULTS: The EMG activity was significantly lower for position A compared to positions C and B (p < 0.05). No significant difference was found between positions B and C. The number of threaded pearls as an indicator for task performance was highest for position B. The difference was statistically significant compared to position C (p = 0.0008) but not between positions A and C (p = 0.0508) or A and B (p = 0.0575). When asked for the preferred monitor position, nine subjects chose two monitors in the frontal positions A and B. No subject preferred the monitor at the side position (C). CONCLUSION: Regarding EMG data, the monitor positioned frontal at eye level is preferable. Reflecting personal preferences of subjects and task performance, it should be of advantage to place two monitors in front of the surgeon: one in position A for lowest neck strain and the other in position B for difficult tasks with optimal task performance. The monitor position at the side is not advisable.

Computer Terminals↗

PubMed1991

Clinical correlates of response to botulinum toxin injections.

We studied 242 patients with cervical dystonia who had adequate follow-up after botulinum toxin injections to determine which clinical variables had a predictive value in the treatment outcome. Twenty-one patients (16%) categorized as nonresponders were compared with 113 patients (47%) considered to be definite responders. On average, the nonresponders had symptoms for 14 years longer than responders. Seventy-eight of 100 patients with complications were female compared with 54% of 190 patients without complications. In addition, patients with complications weighed less than those without complications. Both findings suggest that the occurrence of complications is related to smaller mean neck muscle mass. Botulinum toxin antibodies were detected in 35.7% of the nonresponders tested and in none of the responders. This comprehensive analysis of outcome variables leads us to conclude that patients with a long duration of dystonia before their first botulinum toxin injection respond less well than those with a short duration of symptoms, that some patients lose their responsiveness because of the development of blocking antibodies, and that women are more likely to develop complications, such as dysphagia and neck weakness, than are men.

Adolescent↗

PubMed2004

Use of modified Northwick Park Neck Pain Questionnaire in patients with postirradiation neck disability: validation study.

BACKGROUND: No available measure exists for postirradiation neck disability. Adoption of the Chinese Northwick Park Neck Pain Questionnaire (NPQ) for patients with postirradiation neck disability was examined in this study. METHODS: Eight physiotherapists and five patients were invited to test the validity of the content. Forty-three patients with neck disability were recruited to evaluate test-retest reliability and internal consistency. The level of neck discomfort, range of neck motion and maximal isometric neck muscle strength, and SF-36 health score were measured for construct validity testing. RESULTS: The questionnaire had good content validity, a high degree of test-retest reliability, internal consistency (intraclass correlation coefficient [ICC], 0.94; Cronbach's alpha, 0.88), and good construct validity. NPQ correlated significantly with most of the subscores of SF-36 (r(s), -0.43 to - 0.71) and numeric rating scale (r(s) = 0.69). CONCLUSION: The modified Chinese NPQ was found to be reliable and valid for the evaluation of postirradiation neck disability.

Adult↗

PubMed1986

Research summary of a scheme to ascertain the availability of speech information in the myoelectric signals of neck and head muscles using surface electrodes.

The availability of speech information in the myoelectric signals (MES) of neck and head muscles was observed during five experiments conducted on two subjects. The MES of four channels, obtained using surface electrodes, was analog amplified, filtered and enhanced prior to digitization. Information was extracted at the rate of 20 points per second per channel using an average magnitude algorithm. The presence of speech related information was statistically verified with a pattern recognition algorithm based on the maximum likelihood algorithm. The results indicated that statistically significant (p = 0.01) information was present and that this scheme might be valuable in the future development of a vocal prosthesis.

Adult↗

PubMed2004

Botulinum toxin A for the treatment of cervical dystonia.

Idiopathic cervical dystonia (ICD) is the most common adult-onset focal dystonia. It is characterised by relatively sustained, involuntary contractions of neck muscles. Injections of botulinum toxin (BTX)-A are safe and effective for the treatment of ICD, and have substantially improved its treatment. BTX-A is manufactured by Allergan Pharmaceuticals in the US and Ireland, and is distributed as Botox. In Europe, BTX-A is manufactured and distributed by Ipsen Pharmaceuticals as Dysport. Success rates for BTX-A injections for ICD ranges 64-90%, with 76-93% of injected patients experiencing pain reduction. Side effects are generally mild and include dysphagia and neck weakness.

Adult↗

PubMed1983

The structure of the bladder neck in male bladder neck obstruction.

A light microscope and neurohistochemical study is presented of full thickness biopsies from the bladder neck of 10 middle-aged males with urodynamically proven bladder neck obstruction. Apart from varying degrees of collagen deposition in seven cases, no abnormality was present in the detrusor and pre-prostatic components of the bladder neck muscles or in the distribution of cholinergic nerve fibres. The normal noradrenergic innervation to the pre-prostatic sphincter was absent in all specimens; this may be age-related.

Adult↗

PubMed1995

Dependence of the adequacy of muscle relaxation on the degree of neuromuscular block and depth of enflurane anesthesia during abdominal surgery.

We studied the intensity of neuromuscular block that is adequate for surgical relaxation at different end-tidal levels of enflurane during N2O-O2-fentanyl anesthesia in 30 patients undergoing upper abdominal surgery. After induction of anesthesia with thiopental 4-6 mg/kg and vecuronium 0.07 mg/kg intravenously (i.v.), patients were randomly assigned to receive nitrous oxide-oxygen (2:1) and enflurane at 0.3% (Group I), 0.6% (Group II), or 1.2% (Group III) end-tidal level throughout anesthesia. The initial neuromuscular block was allowed to terminate and additional increments of 1 mg vecuronium were given when indicated by clinical signs or by spontaneous electromyography of neck muscles. In Group I additional vecuronium had to be given 62 times and in Groups II and III, 33, and 16 times, respectively. The mean (SD) neuromuscular block at the time of additional vecuronium was 75.9% +/- 20.7%, 62.5% +/- 20.1%, and 39.3% +/- 21.1% in Groups I to III, respectively. We conclude that there was a clear linear relationship between the end-tidal concentration of enflurane and the degree of neuromuscular block necessary to produce adequate surgical muscle relaxation (P < 0.001).

Abdomen↗

PubMed2004

Clinical comparison of muscle-specific tyrosine kinase (MuSK) antibody-positive and -negative myasthenic patients.

We assayed cryopreserved sera from 38 acetylcholine receptor (AChR) antibody-negative patients with myasthenia gravis (MG) who were followed clinically for muscle-specific tyrosine kinase (MuSK) antibodies and analyzed and compared their clinical characteristics. None of 13 sera from patients with purely ocular MG were positive. Sera from 10 of 25 patients (40%) with generalized MG were positive for MuSK antibodies. The age at onset of myasthenic symptoms was significantly earlier in MuSK antibody-positive patients (P = 0.02). MuSK antibodies were present in AChR antibody-negative patients of either gender, with virtually identical prevalence in women (41.2%) and men (37.5%). The distribution of weakness more commonly involved neck muscles in MuSK antibody-positive patients, and limb muscles in MuSK antibody-negative patients. Patients responded to immunosuppressive treatment regardless of whether MuSK antibody was present. We conclude that MuSK antibodies are present and diagnostically useful in a subset of myasthenic patients without AChR antibodies. Although the distribution of weakness differs somewhat depending on whether MuSK antibodies are present, responses to anticholinesterase and immunosuppressive treatments are similar.

Adult↗