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[The study of facial neurapraxia].

OBJECTIVE: To study the clinical characteristics and mechanism of facial neurapraxia. METHOD: Patients were tested with nerve excitability method and judged the degree of facial paralysis. Animal mode of neurapraxia was made and threshold of evoked electromyographic potential was tested. The fibers of facial nerve were observed under transmission electromicroscope. RESULT: Average restoration time of evoked electromyographic potential was 52.5 min. The lamellar separation of myelin sheath of facial nerve was found under electromicroscope. Patients with facial neurapraxia was judged as denervation negative and residual function of facial muscles was above 65%. CONCLUSION: Facial neurapraxia is mild reversible facial paralysis and relevant to the lamellar separation.

Animals↗

[Diagnosis and management of facial nerve neuromas].

OBJECTIVE: To provide the experience for early diagnosis and management of facial nerve neuromas, and to discuss the clinic and imaging feature of facial nerve schwannoma and facial nerve fibroma in 22 cases. METHODS: Twenty cases facial nerve schwannoma and two cases of facial nerve neurofibroma were diagnosed and reviewed retrospectively. Surgical removal were performed through the middle cranial fossa in 2 cases, through intratemporal approach in 8 cases, through intraparotid approach in 2 cases, and combined intra-temporal with out-temporal approaches in 10 cases. Seventeen cases underwent facial nerve graft for repairing a facial nerve defect. Great auricular nerve was used in 3 cases with intratemporal approach and 1 case with intratemporal combined intraparotid approach. Sural nerve graft was used in 5 cases with intratemporal approach and 8 cases with intra-temporal combined intraparotid approach. Two cases were employed two-stage facial muscle flap-plasty. RESULTS: Facial nerve neuromas were totally removed in 21 cases and subtotal neuroma removed in 1 case. In these cases, 20 patients were no recurrence and 1 patient was lost follow-up. One patient with subtotal neuroma removal received Gamma Knife treatment before and after surgery, and this case was no recurrence. The CT imaging of the temporal bone showed that schwannoma was separated "white mass" with smooth margin along the region of facial nerve without intact canal. But neurofibroma locate in enlarge fallopian with intact canal. Magnetic resonance imaging had the advantage of evaluating all segments of the facial nerve and showed continuity of intratemporal and intraparotid mass with the facial nerve. Pathological results indicated that 20 cases were diagnosed as facial nerve schwannoma and 2 cases were neurofibroma. CONCLUSIONS: Although tumors originating from the facial nerve are extremely rare, it is possible to make early diagnosis through finding clinical feature and imaging methods. Generally, systematic surgical approach for tumor removal and facial nerve reconstruction should be considered in the cases with facial neurinoma.

Adolescent↗

[Maxillofacial manifestations of systemic scleroderma. Apropos of a case].

The authors relate the case of one patient 54 years old having a progressive systemic sclerosis. It is a rare progressive disease of unknown etiology. The patient was first seen in 1983, with lesions on the face. The following is the report of this patient who demonstrated resorption of the angle of the mandible, atrophy of the zygomatic arches, characteristics facial muscles and cutaneous lesions.

Facial Muscles↗

Distribution of different fiber types in whole cross-sections of human platysma. A histological and morphometric study.

Analysis of cryostat cross-sections of the entire platysma muscle from human autopsies revealed enzyme histochemical and morphometric differences between normal human limb and facial muscles. The mean diameter of platysma fibers was about 50% of that of normal limb muscle fibers. Fiber type diameter increased from the medial to the lateral parts of the platysma. A variability coefficient of 356 indicated great variation in fiber caliber, with many fibers of 10 microns and less. Type I fibers showed an increase in density from the medial to the lateral parts of the muscle. The arrangement of histochemical fiber types was irregular with a tendency to form fiber type groupings.

Adult↗

Facial electromyography and emotional reactions.

The aim of this paper is to review data from my laboratory, which were collected in an attempt to determine whether the facial EMG response is a general component of the emotional reaction. In a number of studies it was found that facial reactions: first, are spontaneously elicited and differ according to the kind of emotional stimuli to which subjects are exposed; second, are sensitive to learning; third, are consistent with how the subjects perceive the stimuli and their own specific emotions; fourth, are congruent with autonomic responses; fifth, are more pronounced for females than for males; and finally, differ among subjects with specific fears. These data converge to indicate that facial muscle activity is a general component of the emotional reaction and demonstrate that the facial EMG technique is a sensitive tool for measuring emotional reactions.

Adult↗

Fibre type proportions of the buccinator muscle in clinically normal adult dogs.

In order to provide normal morphological data and reference values for fibre type proportions, against which changes due to facial nerve paralysis or primary facial muscle myopathies can be compared, a histological and histochemical study was carried out on the buccinator muscle of clinically normal adult dogs. Using myosin adenosine triphosphatase under acidic pre-incubation (pH 4.3) conditions, three histochemical fibre types--1, 2A and 2C were recognised. There was no significant difference in mean diameter between left- and right-sided buccinator muscle samples for type 1 versus 2. Mean diameters of fibre types were: type 1, 27.02 +/- 6.61 microns and type 2, 29.05 +/- 7.75 microns. The histographical distribution of fibre type diameters was unimodal. The buccinator muscle had a type 2 fibre predominance with a mean type 1 to type 2 ratio of 32:68. The number of fibres with internal nuclei was less than or equal to 1 per cent, atrophy-hypertrophy factors typically were less than or equal to 200, and variability coefficients approximated 250. Muscle spindles were not observed in any muscle sample.

Animals↗

Perception of activity in the Zygomaticus major and Corrugator supercilii muscle regions.

This study was designed to assess differences in perception of activity in the zygomaticus major (predominant during smiling) and corrugator supercilii facial muscles (predominant during frowning). Magnitude production psychophysical methods were used to relate subjective intensity to objective electromyographic activity using a psychophysical power function under four conditions: smiling, frowning, smiling concurrent with maintenance of a frown, and frowning concurrent with maintenance of a smile. High correlation coefficients for each power function for both zygomatic and corrugator activity were obtained. Differences in sensitivity evaluated by comparing the exponent for slope of the power functions showed differences across the muscles and as a function of the conditions. The exponent for frowning was greater than for smiling. Although the exponent for zygomatic activity was similar with and without frowning, significantly greater exponents were shown for corrugator activity when concurrently frowning and smiling than when only frowning. Maximal electromyographic activity was greater in the zygomaticus major muscle during smiling than in the corrugator supercilii muscle during frowning. These results provide a methodology for perception of electromyographic activity which could be a useful basis for analysis of the role of perception in regulating affect.

Adolescent↗

EMG analysis of the upper and lower fascicles of the orbicularis oris muscle in deaf individuals.

The aim of this study was to analyze electromyographically the upper and lower fascicles of the orbicularis oris muscle in deaf patients comparing them with clinically normal patients. These patients present several disorders in facial muscles, temporomandibular joints disorders and constantly headache in virtue of not the use of the face expression muscles. This was performed in 30 patients from both sexes with a mean age of 18.5 years, divided into 3 groups of 10 patients each: 1. deaf patients with buccal breathing and incompetent lips; 2. in deaf patients with nasal breathing and competent lips; 3. clinically normal patients, in 7 clinical conditions: at rest with and without labial contact, sucking water, blowing, pursing and reciprocal compression of the lips and the emission of the syllabi "PA". It was observed that in the deaf patients group, both fascicles of the orbiculares oris muscles presented hyperactivity in most of the analyzed movements, mainly in buccal breathing with incompetent lips, and the lower fascicle demonstrated the highest electromyographic activity.

Adolescent↗

[Abnormal head drooping in facioscapulohumeral muscular dystrophy].

Diagnosis of facioscapulohumeral muscular dystrophy (FSHD) is based on its characteristic pattern of muscle wasting. Initial symptom is usually shoulder girdle and upper arm muscle wasting resulting in difficulty in arm-lifting. Patients are aware of progressive change of facial appearance caused by characteristic facial muscle weakness. Affection of other muscles is usually realized much later, but, there is a considerable variation in pattern and severity between individuals even in the same family so that several clinical subtypes such as jump form or scapuloperoneal syndrome have been proposed. Here we described three patients with FSHD showing conspicuous head-drooping caused by severe wasting of posterior neck muscles. These patients realized abnormal neck posture much earlier than appearance of obvious gait disability, while they show other characteristic FSHD features. Familial occurrence is observed in two cases, other affected members from both families do not show abnormal head drooping. Therefore we regarded this sign as another example of clinical heterogeneity of this genetic disorder.

Aged↗

Treatment of hemifacial spasm with botulinum A toxin. Results and rationale.

Hemifacial spasm is characterized by unilateral, periodic, tonic contractions of facial muscles, thought to be caused by mechanical compression at the root-exit zone of the facial nerve. Electrophysiologic abnormalities such as ectopic excitation and synkinesis are typical. Although posterior fossa microsurgical nerve decompression is successful in bringing about relief of the spasm in most cases, it carries a risk to hearing. As an alternative treatment, 15 patients with hemifacial spasm were given a total of 41 sets of injections with botulinum A toxin, with a mean follow-up of 14.3 +/- 1.1 months. Relief of symptoms lasted a mean of 108.3 +/- 4.2 days. Mild transient lagophthalmos and ptosis were the only complications. Although the exact mechanism of its action and beneficial effect is speculative at this time, botulinum A toxin appears to offer an effective, safe alternative to more radical intracranial surgery for patients with hemifacial spasm.

Aged↗

Nasolabial musculocutaneous flap in reconstruction of oral defects.

Modern day understanding of the microcirculation of musculocutaneous flaps has initiated this reconsideration of the nasolabial flap with the context of modern flap physiology and nomenclature. Surgical incorporation of the circumoral and facial muscles within the skin of the overlying nasolabial groove constitute a musculocutaneous flap based upon the underlying facial vessels. This thick musculocutaneous flap provides an extremely reliable vascularity for reconstruction of the floor of the mouth and oral sphincter in a one-stage procedure. The donor nasolabial flap is easily accessible in the same surgical field and may be obtained with minimal donor area morbidity. Cosmetic and functional impairment are minimal. Anterior tongue mobility for articulation is preserved. Eleven nasolabial flaps for oral reconstruction following burn reconstruction as well as resections for carcinomas of the labial and oral areas are presented.

Aged↗

Facial myokymia due to acoustic neurinoma.

The case of a 62-year-old female patient who presented with facial myokymia is reported. The patient had a 13-year history of progressive left-sided hearing loss. In further course, involuntary, wormlike, rippling movements of the left facial muscles developed. Computed tomography revealed a tumor located in the left cerebellopontine angle. Electrophysiologic examinations confirmed the diagnosis of facial myokymia. The tumor, which evolved from the eighth cranial nerve, was totally removed microsurgically. The tumor was histologically verified to be an acoustic neurinoma. Postoperatively, the patient had a facial nerve paralysis, and the facial myokymia was no longer present. The present case provides further evidence that facial myokymia may be triggered by alterations at one of various sites along the course of the motor axons of the facial nerve.

Facial Muscles↗

Myokymic discharges and enhanced facial nerve reflex responses after recovery from idiopathic facial palsy.

A functional disorder of facial muscle activity commonly occurs in patients after recovery from Bell's palsy with axonal degeneration. The postparalytic facial dysfunction is probably related to the aberrant growing of regenerating axons, although other theories such as ephaptic transmission, spontaneous generation of impulses, and enhancement of motoneuron excitability should also be considered. In this work, we have carried out a comparative electrophysiological study of both sides of the face in 23 patients who had recovered from a unilateral Bell's palsy with axonal degeneration. At rest, spontaneous firing of motor units was observed in muscles of the previously paralyzed side. Direct motor responses to facial nerve stimulation were smaller in the muscles of the previously paralyzed side, but reflex responses obtained in the same muscles by stimulation of either the facial or trigeminal nerve were larger when compared with those of the contralateral side. These data indicate that patients with "postparalytic facial dysfunction" may have an increased background muscle activity, as well as an enhanced recruitment of facial motoneurons to reflex activation in the side of the previous paralysis. These findings are compatible with an enhanced level of motoneuron excitability in the facial nucleus.

Action Potentials↗

Sequential neuromuscular changes in rhesus monkeys during the initial adaptation to oral respiration.

Experimental induction of oral respiration in primates altered the neuromuscular use of specific craniofacial muscles. Obstruction of the nasal passage in the rhesus monkey induced changes in the electromyographic discharge (EMG) of both mandibular and facial muscles during the first 6 months of adaptation. Eighteen craniofacial muscles were studied with regard to their type of neuromuscular pattern. The EMG discharge was analyzed in terms of whether it had a rhythmic discharge or a continuous recruitment of motor units. The results of the investigation revealed that certain muscles in the control monkey using nasal respiration could be rhythmically or continuously active, but no significant trend was apparent with either pattern over time. In contrast, a significant number of muscles became rhythmically active within the first month of adaptation to oral respiration in the experimental animals. The rhythmic pattern was evident in key muscles that actively depressed the mandible, protruded the tongue, altered the shape of the tongue, and raised the upper lip. Continuous activity was induced in the first month within the suprahyoid region and tongue but later, by the fifth month, in specific lip and elevator muscles. These results suggested that the neuromuscular system adapted immediately to nasal obstruction but would vary as to (1) which muscles would be important in the initial adaptation, (2) the mode of adaptation, and (3) the time when a particular pattern first began to be used.

Adaptation, Physiological↗

[Treatment of Bell's palsy by using portable biofeedback devices].

Portable, electromyographic feed-back devices were used to develop a scheme for staged and directed correction of motor function of facial muscles. The scheme was applied to the treatment of 32 patients aged 17 to 60 years with neuritis and neuropathy of the facial nerve. As a result of the treatment, the patients manifested the improvement of coordinative interrelations between the analogous groups of muscles of the diseased and normal side of the face (activation of weakened muscles with simultaneous abatement of the intensity of pathologic synergisms), evidencing the returning to normal of the central programs that control movements.

Adolescent↗

Expression of different isoforms of nitric oxide synthase in experimentally denervated and reinnervated skeletal muscle.

Denervated muscle fibers express enhanced levels of stress and apoptosis-associated proteins and undergo apoptosis. In experimentally denervated and reinnervated rat facial muscle, we now evaluate changes in the expression patterns of different isoforms of nitric oxide synthase (NOS)-generating nitric oxide (NO), which mediates oxidative stress and apoptosis. Physiological expression of NOS corresponds to a constant sarcolemmal staining pattern for neuronal NOS (nNOS) and a patchy sarcolemmal and weak sarcoplasmic labeling for the endothelial NOS-isoform, with no expression for inducible NOS (iNOS). Denervated muscle displayed distinct downregulation of nNOS with preserved expression of dystrophin. Also, denervated and immediately reinnervated muscle fibers showed decreased expression of nNOS. However, muscle fibers reinnervated for 10 weeks revealed a restored physiological expression of nNOS. There were no changes in the expression of endothelial and inducible NOS. As NO is known to induce growth arrest and collapse of neuronal growth cones, downregulation of NOS may contribute to promotion of axonal regeneration by aiding formation of new endplates. NO is upregulated in reinnervated muscle fibers and thus prevents polyneural hyperinnervation by extrajunctional synapses. Furthermore, downregulation of NOS during denervation is compatible with the finding that low levels of NO contribute to apoptosis instead of necrosis in disease states of oxidative stress.

Animals↗

Rapid facial reactions to emotional facial expressions.

This study explored how rapidly emotion specific facial muscle reactions were elicited when subjects were exposed to pictures of angry and happy facial expressions. In three separate experiments, it was found that distinctive facial electromyographic reactions, i.e., greater Zygomaticus major muscle activity in response to happy than to angry stimuli and greater Corrugator supercilii muscle activity in response to angry stimuli, were detectable after only 300-400 ms of exposure. These findings demonstrate that facial reactions are quickly elicited, indicating that expressive emotional reactions can be very rapidly manifested and are perhaps controlled by fast operating facial affect programs.

Adult↗