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PubMed2001

Myo-electric signals to augment speech recognition.

It is proposed that myo-electric signals can be used to augment conventional speech-recognition systems to improve their performance under acoustically noisy conditions (e.g. in an aircraft cockpit). A preliminary study is performed to ascertain the presence of speech information within myo-electric signals from facial muscles. Five surface myo-electric signals are recorded during speech, using Ag-AgCl button electrodes embedded in a pilot oxygen mask. An acoustic channel is also recorded to enable segmentation of the recorded myo-electric signal. These segments are processed off-line, using a wavelet transform feature set, and classified with linear discriminant analysis. Two experiments are performed, using a ten-word vocabulary consisting of the numbers 'zero' to 'nine'. Five subjects are tested in the first experiment, where the vocabulary is not randomised. Subjects repeat each word continuously for 1 min; classification errors range from 0.0% to 6.1%. Two of the subjects perform the second experiment, saying words from the vocabulary randomly; classification errors are 2.7% and 10.4%. The results demonstrate that there is excellent potential for using surface myo-electric signals to enhance the performance of a conventional speech-recognition system.

Adult↗
PubMed1994

Auditory steady-state response, upper facial EMG, EEG and heart rate as predictors of movement during isoflurane-nitrous oxide anaesthesia.

We have studied the relationship between patient movement and changes in the auditory steady-state evoked potential, upper facial muscle electromyogram (FEMG), electroencephalographic-zero crossing frequency (EEG-ZCF) and heart rate during emergence from anaesthesia. Twelve healthy patients underwent surgery during stable isoflurane-nitrous oxide-oxygen anaesthesia without neuromuscular block. After skin closure, anaesthesia was discontinued abruptly while mechanical ventilation was continued until the patient moved. The magnitude of change in each physiological signal was evaluated in decibels (dB). Both the auditory steady state evoked potential and FEMG showed significant increases in amplitude during the last 5-min period before movement (6.1 and 10.7 dB, respectively). EEG-ZCF increased rapidly after anaesthesia was discontinued (2.5 dB) but there was no further increase in activity before movement. Heart rate did not change before movement. The use of the decibel transformation offers a promising method of displaying and interpreting changes in physiological variables during anaesthesia.

Adult↗
PubMed1990

Facial reactions to auditory stimuli: sex differences.

This study explored whether males and females differ in facial muscle activity when exposed to tone stimuli with different intensity. Males and females were repeatedly exposed to 95 dB and 75 dB 1000 Hz tones while their facial electromyographic (EMG) activity from corrugator and zygomatic muscle regions were measured. Skin conductance responses were also measured. It was found that 95 dB but not 75 dB tones evoked increased corrugator activity. This effect differed significantly between males and females. Thus, it was only females that reacted with a significant increased corrugator response to the high intensity tone. While facial responses differed between the sexes, the skin conductance response patterns did not. Consistent with previous research it is concluded that females are more facially expressive than are males.

Adult↗
PubMed1990

Low threshold unilateral and bilateral facial movements evoked by motor cortex stimulation in cats.

Organizational features of the ipsilateral representation in the cat face motor cortex were investigated by using the technique of intracortical microstimulation (less than 30 microA). In 4 intact animals, 61 efferent zones controlling facial muscles were identified. They were devoted to contralateral muscles (contralateral efferent zones; n = 35), ipsilateral muscles (ipsilateral efferent zones; n = 8) or symmetrical muscles of both sides (bilateral efferent zones; n = 18). Contralateral efferent zones were found within both the rostral part of the coronal gyrus and the lateral bank of the presylvian sulcus, whereas ipsilateral and bilateral efferent zones were exclusively localized to the rostromedial region of the face motor cortex. Movement thresholds proved to be lowest at the contralateral efferent zones and highest at the ipsilateral efferent zones, with intermediate values at the bilateral efferent zones. Latencies of suprathreshold EMG responses evoked from contralateral and ipsilateral efferent zones were the shortest and the longest, respectively; intermediate values were found upon stimulation of sites from bilateral efferent zones. The efferent zones identified in 3 lesioned animals (two cats with contralateral motor cortex ablation and one cat with transection of the rostral two thirds of the corpus callosum) were contralateral (n = 14), bilateral (n = 13), and ipsilateral (n = 9). Mean thresholds of effective sites from bilateral and ipsilateral efferent zones in lesioned preparations were not significantly higher than those in intact animals. This would thus suggest that extracallosal pathways may account for ipsilateral responses.

Animals↗
PubMed1989

Botulinum toxin therapy in hemifacial spasm: clinical and electrophysiologic studies.

Three patients with idiopathic hemifacial spasm were studied clinically and electrophysiologically before and after injections of botulinum toxin into the involved periocular and facial muscles. The spasms were improved for approximately 3 months, and the effect was repeatable on reinjection. The spasms diminished only as long as the muscles were clinically weak, and spasms were observed electromyographically even though therapy eliminated the clinical spasms. Uninjected muscles continued to have spasms. Transmission of excitation from the zygomatic branch to the marginal mandibular branch of the facial nerve and vice versa in all patients was unaltered after therapy, but the amplitude of the response was decreased. The efficacy of botulinum toxin in hemifacial spasm appears to be related to the production of muscle weakness; there is no demonstrable effect on phenomena believed to be ectopic excitation or ephaptic transmission in the facial nerve.

Adult↗
PubMed1990

Blepharospasm, hemifacial spasm and the nurse's role.

Blepharospasm and hemifacial spasm are involuntary movement disorders that affect the facial muscles. They are classified as cranial dystonias. Their cause is unknown and the underlying pathophysiology is poorly understood. Both dystonias are more common in women than in men. It is the middle-aged group that is most frequently affected. Because of their high visibility, these disorders may cause considerable distress and embarrassment. Affected persons are often mistakenly considered to have psychiatric problems. In addition, both dystonias may result in severe disability. For example, the person with untreated blepharospasm may experience social isolation and functional blindness. Recently, therapy in the form of botulinum toxin became available in larger centers. Repeated injections of the toxin usually relieves symptoms and enable patients to resume a former lifestyle. Neuroscience nurses who are knowledgeable about cranial dystonias and the resources that are currently available can retard progression of disability and help restore the individual's quality of life. Informed neuroscience nurses can also play an important role in case-finding, counselling and referral. Two examples are presented in order to highlight some of the complexities inherent in the diagnosis and treatment of each type of cranial dystonia and to further clarify the nurse's role. These examples are based on the personal and professional experience of the authors.

Adult↗
PubMed1998

Role of the retrorubral nucleus in striatally elicited orofacial dyskinesia in cats: effects of muscimol and bicuculline.

Orofacial dyskinesia (OFD) is a disorder characterized by involuntary movements of the oral and facial muscles. OFD attacks can be elicited acutely in cats by local injections of dopaminergic agents into the anterodorsal part (r-CRM) of the caudate nucleus. Because the dopaminergic A8 cell group, being embedded in the retrorubral nucleus (RRN), gives rise to fibres which terminate in the r-CRM, two questions arose: (1) whether the A8 cell group forms part of the circuitry that directs and/or modulates OFD, and (2) whether GABA-ergic compounds in the RRN play a role in OFD, and if so, whether a pharmacological GABA-ergic intervention of the activity in the RRN modulates or mediates OFD. For this purpose, the activity of the RRN was manipulated with local injections of the GABA(A) agonist muscimol and antagonist bicuculline. These local injections into the RRN were subsequently combined with manipulations of dopamine transmission in the r-CRM with local injections of the selective DAi receptor agonist (3,4-dihydroxyphenylimino)-2-imidazoline. The present study shows that local injections of GABA-ergic compounds into the RRN do not elicit OFD attacks in cats, but can modulate oral behaviour elicited from the r-CRM. The latter effect is dose dependent and GABA-ergic specific.

Animals↗
PubMed1991

Subregions of the caudate nucleus and their in- and output channels in oro-facial dyskinesia: a behavioural and retrograde tracing study in the cat.

Previous studies have shown that the feline caudate nucleus contains DPI-sensitive (caput nuclei caudati, anterodorsal part; r-CRM) and DPI-insensitive (caput nuclei caudati, rostromedial part; CRM) regions. Stimulation of dopamine receptors within the r-CRM by dopamine or DPI are known to elicit oro-facial dyskinesia (OFD), i.e. a syndrome of tic-like contractions of the facial muscles in combination with tongue protrusions. OFD is also elicited from the sub-commissural part of the globus pallidus (scGP), a first order output station of the r-CRM, but not from the CRM. On the basis of these data it has been hypothesized that (1) OFD is a specific feature of the r-CRM, but not the CRM; (2) effects elicited from the r-CRM are funneled via the scGP, and that (3) r-CRM and CRM are differentially innervated. Cats were bilaterally equipped with cannulas directed at the CRM or r-CRM and scGP. Following recovery from the operation the cats received bilateral injections of DPI into CRM (5 micrograms/5 microliter) or r-CRM (5 and 10 micrograms/5 microliter), the latter in combination with muscimol (50 and 100 ng/1 microliter) into the scGP or its solvent. Subsequently, behaviour was analyzed. OFD, quantified in number of tongue protrusions, was only elicited from the r-CRM, but not from the CRM confirming previously reported data in this respect. Furthermore the effect varied according to the dose used. The OFD elicited from the r-CRM was found to be blocked at the level of the scGP by local injections of muscimol, a GABA agonist.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1980

[Electrodiagnosis of the facial and ocular muscles (author's transl)].

The eletrodiagnosis of the muscles of the face and eyes are presented according to their historical development. Then the present-day technical possibilities in the different medical fields are explained with emphasis on neurology and psychiatry, illustrated by some clinical descriptions. Selective electromyelography of individual muscles, polygraphic analysis of synergistic or antagonistic reflex mechanismus and the combined biometric methods of psychophysiology are differentiated.

Electrodiagnosis↗
PubMed1999

Relationship between muscle activity of the frontalis and the associated brow displacement.

Although the relationship between regional facial muscle activity and resultant displacement of the face is important to the refinement of many of the treatments of facial paralysis and palsy, this relationship has not been adequately explored. We analyzed the relationship between frontalis muscle activity as measured with surface electromyography and the associated eyebrow displacement as measured with the maximal static response assay in 16 human volunteers. We hypothesized that graded, sustained muscle activity would correlate with graded, sustained elevation of the eyebrow. We found that (1) the relationship between the muscle activity and the corresponding displacements was best described by activity versus displacement squared (r2 = 0.993); (2) there was a wide variation between individual brows for the relationship between muscle activity and displacement; (3) there was a normal amount of asymmetry of the relationship between muscle activity and displacement between the two brows of a subject; (4) left and right frontalis generated the same amount of muscle activity, but left brows elevated significantly higher; (5) the method of simultaneous measurement of muscle activity and displacement used in this study yielded results similar to those previously reported; and (6) the methods used in this study are useful to further investigate the relationship between muscle activity and displacement.

Adult↗
PubMed1999

Unmasking of the trigemino-accessory reflex in accessory facial anastomosis.

OBJECTIVE: To evaluate the possible blink reflex responses in facial muscles reinnervated by the accessory nerve. METHOD: Eleven patients with a complete facial palsy were submitted to a surgical repair by an accessory facial nerve anastomosis (AFA). In this pathological group, blink reflex was studied by means of percutaneous electrical stimulation of the supraorbital nerve and recording from the orbicularis oculi muscle. A control group comprised seven normal people and seven patients with a complete Bell's facial palsy; in this group, responses on the sternocleidomastoideus (SCM) muscles were studied after supraorbital nerve stimulation. RESULTS: All the patients with AFA showed a consistent degree of facial reinnervation. Ten out of the 11 patients with AFA showed reflex responses; in six, responses were configured by a double component pattern, resembling the R1 and R2 components of the blink reflex; three patients had an R1-like response and one patient showed a unique R2 component. Mean values of latencies were 15.2 (SD 4.6) ms for the R1 and 85.3 (SD 9.6) ms for the R2. In the control group, eight out of 14 people had evidence of reflex responses in the SCM muscles; these were almost exclusively configured by a bilateral late component (mean latency 63.5 (SD15.9) ms) and only one of the subjects showed an early response at 11 ms. CONCLUSION: The trigemino-accessory reflex response in the pathological group was more complex and of a significantly higher incidence than in the control group. These differences could be tentatively explained by a mechanism of synaptic plasticity induced by the impairment of the efferent portion of the reflex. This could unmask the central linking between the trigeminal and the accessory limbs of the reflex. The findings described could be a demonstration of neurobionomic function in the repairing process of the nervous system.

Accessory Nerve↗
PubMed1993

Newly recognized congenital myasthenic syndrome associated with high conductance and fast closure of the acetylcholine receptor channel.

We describe here a new congenital myasthenic syndrome associated with a kinetic abnormality of the acetylcholine receptor (AChR) channel. The propositus had poor suck and cry after birth. Subsequently, she had intermittent ocular symptoms and fatigued abnormally on exertion. At age 9 years, significant weakness was detected only in the frontalis, levator palpebrae, and neck flexor muscles. Electromyography showed no decrement in limb muscles but single-fiber examination of the facial muscles was consistent with a neuromuscular transmission defect. The ocular symptoms responded partially to pyridostigmine, but the abnormal fatigability did not. Tests for anti-AChR antibodies were negative. A younger sister had elements of the same disease. An intercostal muscle specimen was obtained from the propositus at age 9 years for endplate studies. The quantal content of the endplate potential was normal. Miniature endplate currents were abnormally large and their decay time constant was abnormally short. AChR channel properties were studied by analysis of acetylcholine-induced current noise. The mean single-channel conductance was increased 1.7-fold and the mean channel open time was 30% shorter than normal. The number of AChR per endplate was normal. Electron microscopy of most endplates showed no abnormality, but a few were degenerating or simplified. The channel abnormality may stem from a point mutation in an AChR subunit affecting a single amino acid residue lining the pore of the AChR channel. The mechanism by which the physiological abnormality produces clinical symptoms is not known, but possible explanations are considered.

Adult↗
PubMed1996

Lattice corneal dystrophy type II associated with familial amyloid polyneuropathy type IV.

BACKGROUND: Finnish-type familial amyloidosis (FAP-IV) is an autosomal, dominantly inherited disorder characterized by progressive polyneuropathy and lattice corneal dystrophy type II. The vast majority of families with this disorder originated from Finland. Only two families, in neighboring districts, have been reported in Japan previously. METHODS: The authors report two additional Japanese patients with FAF-IV. The proband, a 70-year-old man, had decreased perspiration and abnormal facial muscle movement. Results of neurologic examination showed bilateral facial and hypoglossal nerve palsies, and an autonomic disturbance, including orthostatic hypotension and dysfunction of perspiration. Histochemical, immunohistological, and DNA studies confirmed the diagnosis of FAP-IV. RESULTS: Results of ophthalmologic examination showed asymptomatic lattice corneal dystrophy of both eyes, but the appearance of the cornea was different from that described in the patients from Finland. Lattice lines in the authors' patient were very fine, short, and glassy and could be observed with indirect retroillumination, but might be missed with direct illumination by the slit-lamp microscope. The proband's younger half-sister, a 68-year-old woman, showed clinical findings and laboratory data similar to those of the proband. CONCLUSION: The authors report two Japanese patients with lattice corneal dystrophy type II related to FAP-IV. This is the third Japanese family with this disorder, and there is no familial relationship to the two previously reported families in Japan.

Aged↗
PubMed2003

Paralyzed masseter muscle reinnervation by facial nerve implantation or anastomosis: a comparative study in rabbits.

OBJECTIVE: To investigate the changes in the physiological and structural properties of the masseter muscle after reinnervation through different reinnervation methods. METHOD: Twenty-four adult rabbits were randomly divided into groups A and B (n=12) after the establishment of masseter muscle paralysis, followed by facial nerve anastomosis with the masseteric nerves in group A and facial nerve implantation into the masseter muscle in group B. At 1, 3 and 6 months after the operation, gross observation and wet weight measurement of the muscles were conducted along with myoelectric activity and enzyme- histochemical analyses and ultrastructural observation as well. RESULTS: The reinnervation of the masseter muscle by both facial nerve anastomosis and implantation was confirmed and the muscles recovered their motion of contraction activity. Changes took place in the histochemical types of the muscle fibers, which tended to assume the properties typical of facial muscles. Three months after the operation, the muscle fiber conduction velocity recovery after the reinnervation by the two methods was significantly different (P<0.01), but not so till 6 months postoperatively (P>0.05). CONCLUSION: This two methods are both effective in the reinnervation of the muscles, but in one-stage operation, intramuscular nerve implantation is relatively less complicated in operation and causes less damage while producing similar effects to that by nerve anastomosis.

Anastomosis, Surgical↗
PubMed1995

[Familial amyloidosis of the Finnish type (FAP) with extraocular muscle involvement].

Among 17 patients with amyloid polyneuropathy type IV in a Japanese family, we found a 72-year-old woman, who showed extraocular symptoms approximately 10 years after the onset of the disease. she developed weakness of the right facial muscles and dysarthria at age 57. She had atrophy and disturbance of movement of the tongue, along with difficulty in swallowing at age 62. At the age of 66, she felt diplopia when she looked toward the left, followed by difficulty of ocular movement. These manifestations progressed and at age 72, she was found to have mild ptopsis, mild to moderate disturbance of almost all extraocular muscles, moderate to severe disturbance of facial, masseter, pharyngeal, tongue and neck muscles. She also had slight weakness and atrophy of the limb and truncal muscles together with slight loss of pain and vibratory sensations in the distal parts of the limbs. FAP IV has sometimes been called cranial amyloidosis, but motor disturbance is limited to the middle and lower cranial nerve territories in the majority of the reported cases, and manifestations of the extraocular muscles are quite rare. According to the present investigation of the world literature, this is the second case of FAP IV with extraocular muscle involvement.

Aged↗
PubMed2001

Silent period in the mentalis muscle induced by facial nerve and cutaneous stimulation.

The aim of this study was to demonstrate that silent periods of the mentalis muscle are induced after facial nerve stimulation and cutaneous stimulation in normal subjects. When the marginal mandibular branch of the facial nerve and the cutaneous nerve in areas adjacent to the lower lip were stimulated during slight voluntary contraction of the mentalis muscle, silent periods were elicited with surface electrodes on the mentalis muscle. The early phase and the late phase of the silent period were elicited by marginal mandibular branch stimulation. The early phase of the silent period was recognized following the F waves and it disappeared at 36.3 msec. The average duration of the late phase of the silent period was 59.2 msec, with an average latency of 62.5 msec. Only the late phase of the silent period after cutaneous stimulation could be elicited, with a duration and latency of 55.9 msec and 54.0 msec respectively. The authors conclude that the silent period is able to be elicited in the mentalis muscle by peripheral nerve stimulation, and is one of the late responses in facial muscles.

Adult↗