Electromyography of the infrahyoid muscles - part 2: pathological findings]

BACKGROUND: The infrahyoid muscles (IHM) can easily be used as a neurovascular myofascial flap for reconstructive surgery in the oral cavity and pharynx and especially for functional tongue reconstruction following tumor ablation. METHODS: In order to detect neurogenic lesions caused by neck pathologies, in particular lymph node metastasis, we studied ten patients (nine patients suffering from tongue carcinoma and one patient after traumatic tongue ablation) by preoperative electromyography of the IHM. These results were compared to ten healthy controls. RESULTS: We found no pathological spontaneous activity with the EMG at rest in any patient. During light voluntary innervation, the motor unit potentials (MUP) were normal in controls and in patients with normal ultrasound, CT scans and histologic examination after neck surgery. When pathologic lymph nodes were found in the neck, the number of polyphasic MUP in the ipsilateral IHM was increased in some cases (n = 6), and normal in others (n = 5). Traumatic or radiogenic lesions clearly resulted in pathological EMG findings (n = 6). Maximal innervation of the IHM was obtained during head bending and jaw opening. We found no difference in the discharge pattern of both groups. CONCLUSIONS: Due to their extent lymph node metastasis can lead to neurogenic lesions of the cervical ansa of the IHM. Neurogenic damages are most clearly present after traumatic lesions of the neck (prior operations, radiotherapy). EMG at maximal voluntary contraction instead revealed no lesions. The clinical impact of these demonstrated neurogenic lesions need to be studied by measuring the muscle strength of the IHM.     

Electromyography of the infrahyoid muscles - part 3: findings after transposition as a myofascial flap in tongue reconstruction]

BACKGROUND: Due to the preservation of its nerval supply the neurovascular infrahyoid muscle flap in tongue reconstruction enables to prevent atrophy of the musculature. In this study the integrity of the infrahyoid muscles (IHM) after transposition into the oral cavity was examined by means of electromyography. METHODS: 17 patients after partial or complete reconstruction of the tongue with IHM were studied at varied times after surgery. The IHM in the oral cavity was inserted by a concentric needle electrode and activity at rest as well as the discharge pattern at maximal voluntary innervation was evaluated. During light voluntary activity a motor unit potential (MUP) analysis were performed. RESULTS: 13 of 17 patients (76,5 %) in total revealed electromyographic activity in the transfered IHM flaps. Within the first 6 months after surgery 71,5 % of the patients or 77,8 % of the IHM flaps showed activity. After 6 months in 61,5 % of the patients or 64,7 % of the IHM flaps muscular activity was demonstrated. In 84,6 % of the patients or 88,2 % of the flaps we could detect neurogenic lesions at least once. Maximal voluntary contraction showed a discrete activity pattern in 63 %. In 26 % of all cases we found a discrete to reduced interference pattern and in 10 % a reduced interference pattern. CONCLUSIONS: Functioning muscle tissue could be demonstrated in the most IHM flaps, but almost all of the studied muscles showed neurogenic lesions with a loss of motor units due to the traumatic surgery. Maybe bioelectrical stimulation of the Ansa cervicalis with implantable amplifiers will lead to better flap contractility in the future.     

Tongue reconstruction: recent advances

PURPOSE OF REVIEW: To examine the recent literature concerning advances in tongue reconstruction after tumor resection. RECENT FINDINGS: Reconstruction following resection of malignant tongue tumors remains one of the most difficult problems in head and neck oncology. Recent trends in tongue reconstruction have focused on optimizing speech and swallowing function and maximizing quality of life. In the recent literature, several new reconstructive strategies including omohyoid musculocutaneous and myofascial flaps overlayed with radial forearm free flaps have been described. In addition, several older reconstructive options, such as trapezius and pectoralis rotational flaps, have been revisited. There has also been a trend toward restoring innervation to these flaps rather than leaving them insensate. SUMMARY: Tongue cancer resection and subsequent reconstruction pose interesting challenges to the surgeon to maximize postoperative function and quality of life. Attention to the principles of tongue reconstruction and knowledge of the range of available reconstructive options can result in more favorable functional outcomes.     

Electromyography of the human nasal muscles

Electromyographic (EMG) activity of six nasal muscles was monitored in 17 male volunteers without nasal complaints. Surface electrodes were placed on the nasal skin in such a way that they selectively recorded the activity of these muscles. Recordings were made under different breathing conditions and during voluntary nasal movements. Inspiratory EMG activity was observed during nasal and oral breathing in one or more of the following muscles: dilator naris, nasalis muscle (alar and transverse parts) and apicis nasi. EMG activity increased markedly in response to physical exercise and was more often present in subjects with decreased nasal patency. During voluntary nasal movements a combined activity of the six nasal muscles was consistently found. We conclude that the function of the dilator naris, the nasalis muscle and the apicis nasi strongly relates to respiration. These muscles probably contribute to the prevention of collapse of the nasal valve. The role of the procerus and levator labii superioris alaeque nasi seems to be primarily concerned with facial expression.     

Mouth Breathing Syndrome: cervical muscles recruitment during nasal inspiration before and after respiratory and postural exercises on Swiss Ball

OBJECTIVE: This study aimed to evaluate the recruitment of cervical muscles during nasal inspiration before and after breathing and postural exercises on the Swiss Ball in children with Mouth Breathing Syndrome (MBS). METHOD: Surface electromyography from the sternocleidomastoid (SCM), sub-occipitals and upper Trapezius muscles was recorded during nasal inspiration, before and at the end of three months of the treatment. A physical therapy program consisting in muscular stretching and strengthening exercises along with naso-diaphragmatic breathing on the Swiss Ball were carried out for body posture realignment and respiratory training. Nineteen mouth breathing children, mean age of 10.6 years, both genres, were the subjects of this study. In order to establish a comparison between the eletromyographic results (normalized values) obtained from pre and post-physical therapy program it was used the Wilcoxon non-parametric test for dependent data. RESULTS: It was found a significant decrease (p<0.01) in the electromyographic activity during nasal inspiration in all tested muscles after treatment (11.3-3.6% in the SCM, 22.4-11.7% in the sub-occipitals and 8.9-3.1% in the upper Trapezius). At the end of the treatment, the assessed muscles reached lower activity electromyographic levels during nasal inspiration and they became closer of those in the quiet position. CONCLUSION: The lower activity after the physical therapy program in these muscles indicates a less effort of the accessory inspiratory muscles, probably due to a better performance of diaphragm muscle with the improvement of the body posture.     

Eye movements during voluntary head motion with minimized cervical input

Eye movements were recorded using DC-electro-oculography in 20 healthy subjects during sinusoidal voluntary head movements and during similar voluntary head movements with minimized cervical input. The eye movements during these conditions were compared to the vestibulo-ocular reflex (VOR), to the cervico-ocular reaction (COR) and to the active COR (i.e., voluntary stabilization of the head in space while the trunk was moved sinusoidally). Each subject sat with eyes covered on a rotating chair. Sinusoidal movements having an amplitude of +/- 20 degrees and either 0.1 or 0.2 Hz were performed. Voluntary head movements and head movements with minimized cervical input showed no difference in the gain of the slow-phase velocity of the nystagmus, the saccadic activity (cumulated amplitude/time) and the maximum eye deviation. The distribution of saccades around the reversal of head movement in space represents the only significant difference between these conditions. While the saccades appear promptly after reversal during sinusoidal voluntary head movement, they appear during voluntary head movement with minimized cervical input just before the reversal of head movement in space. The direction of saccades always depends on the displacement of the head related to the trunk and is due to cervical input and/or central influences.     

Eye movements during voluntary head motion with minimized cervical input

Summary Eye movements were recorded using DC-electro-oculography in 20 healthy subjects during sinusoidal voluntary head movements and during similar voluntary head movements with minimized cervical input. The eye movements during these conditions were compared to the vestibulo-ocular reflex (VOR), to the cervico-ocular reaction (COR) and to the active COR (i.e., voluntary stabilization of the head in space while the trunk was moved sinusoidally). Each subject sat with eyes covered on a rotating chair. Sinusoidal movements having an amplitude of ±20° and either 0.1 or 0.2 Hz were performed. Voluntary head movements and head movements with minimized cervical input showed no difference in the gain of the slow-phase velocity of the nystagmus, the saccadic activity (cumulated amplitude/time) and the maximum eye deviation. The distribution of saccades around the reversal of head movement in space represents the only significant difference between these conditions. While the saccades appear promptly after reversal during sinusoidal voluntary head movement, they appear during voluntary head movement with minimized cervical input just before the reversal of head movement in space. The direction of saccades always depends on the displacement of the head related to the trunk and is due to cervical input and/or central influences.     

Reproducibility and variability of speech muscle activity in athetoid dysarthria of cerebral palsy

Athetoid dysarthria is thought to result from involuntary movements which are variable and irregular in nature. In this study, electromyographic (EMG) activity recorded from six speech muscles was quantified during repetitions of a test sentence by normal and athetoid adult subjects. In the athetoid subjects the articulation of the test sentence was disrupted intermittently by involuntary activity which usually occurred in the time intervals between the syllables in the test sentence, rather than during articulation of the syllables themselves. The EMG activity associated with each syllable in the test sentence was partitioned into reproducible and variable components. The ratio of the reproducible component to the variable component--the signal-to-noise ratio--did not differ significantly between the two subject groups. In the athetoid subjects, however, the reproducible component of the EMG activity was grossly abnormal. We concluded that this abnormal voluntary activity, rather than variable involuntary activity, was the primary cause of athetoid dysarthria.     

Vestibular adaptation to centrifugation does not transfer across planes of head rotation

Out-of-plane head movements performed during fast rotation produce non-compensatory nystagmus, sensations of illusory motion, and often motion sickness. Adaptation to this cross-coupled Coriolis stimulus has previously been demonstrated for head turns made in the yaw (transverse) plane of motion, during supine head-on-axis rotation. An open question, however, is if adaptation to head movements in one plane of motion transfers to head movements performed in a new, unpracticed plane of motion. Evidence of transfer would imply the brain builds up a generalized model of the vestibular sensory-motor system, instead of learning a variety of individual input/output relations separately. To investigate, over two days 9 subjects performed pitch head turns (sagittal plane) while rotating, before and after a series of yaw head turns while rotating. A Control Group of 10 subjects performed only the pitch movements. The vestibulo-ocular reflex (VOR) and sensations of illusory motion were recorded in the dark for all movements. Upon comparing the two groups we failed to find any evidence of transfer from the yaw plane to the pitch plane, suggesting that adaptation to cross-coupled stimuli is specific to the particular plane of head movement. The findings have applications for the use of centrifugation as a possible countermeasure for long duration spaceflight. Adapting astronauts to unconstrained head movements while rotating will likely require exposure to head movements in all planes and directions.     

Color electromyographic topographic analysis of facial movements

To determine the precise amount of facial function present in patients with facial palsy, color electromyographic (EMG) topograms of the facial movements were made using a computerized system, newly designed and manufactured by the authors. During mimetic movements, such as wrinkling the forehead, closing the eyes, blinking, grinning, and blowing out the cheeks, EMGs from 16 monopolar disk electrodes were concurrently recorded from the frontalis, orbicularis oculi, and orbicularis oris muscles on both sides. The amplitude values of the integrated EMG spikes from each electrode were calculated by an interpolation formula in the computer, and the color topographic figures derived from these calculations were displayed on a ten-color computer monitor. The colors ranged from blue to dark red, and they were related to the amount of muscular activity. This technique was applied to patients with facial palsy to document their degree of mimetic movement loss and the time course of the palsy evolution. The results obtained were reliable and reproducible, and the technique made it easy to quantify the loss of mimetic movements in patients with facial palsy.     

Bilateral omohyoid muscle flap reconstruction for anterior commissure cancer

Partial laryngectomy for anterior commissure cancer often results in a shortened glottis which produces a high pitched strained voice and an inadequate airway lumen which requires permanent tracheostomy. Vocal fold vibration is impaired both by the shortened length and anterior scarring which profoundly affects the myoelastic properties of the larynx. Many different methods of reconstructing the anterior commissure have been attempted with limited success and many require multiple procedures. A method of anterior commissure reconstruction employing bilateral omohyoid muscle flaps has been performed successfully in four patients. The omohyoid muscles and investing fascia are readily available during partial laryngectomy and can be tailored to reconstitute the anterior commissure. The myofascial flaps epithelialize rapidly and there is little tendency for anterior glottic stenosis. The sphincteric function of the larynx remains intact and the vocal quality surpasses other methods of reconstruction employed by the author.     

肩胛舌骨肌瓣修复喉部分切除术后缺损

目的：探讨肩胛舌骨肌瓣修复喉部分切除术后缺损的可行性和临床疗效。方法：对24例声门上型、声门型喉癌患者切除肿瘤和受累的软骨，以肩胛舌骨肌瓣修复组织缺损、重建声门。对于一侧杓状软骨固定患者，切除杓状软骨，在取肩胛舌骨肌瓣同时连带切取一小块舌骨，将小舌骨块固定于杓状软骨缺损处，用残余黏膜覆盖之。声门上型T2、声门型T3以上患者术后接受放射治疗(50～60Gy)。结果：随访1～5年，1例声门上型(T3)患者于术后2年9个月死于局部复发，1例声门型(T3)患者于术后4年3个月死于颈部转移和骨转移。拔管率为95．8％。91．7％的患者发声近乎正常或声哑。吞咽功能全部恢复。结论：经过仔细选择病例，肩胛舌骨肌瓣修复喉部分切除术后缺损、重建声门是积极有效和切实可行的。     

Experimental reinnervation of a strap muscle with a few roots of the phrenic nerve in rabbits.

In order to compare application of the roots of the phrenic nerve to the ansa hypoglossi for laryngeal muscle neurotization, 1 or more roots from the phrenic nerve were implanted into the right sternothyroid (RST) muscle of rabbits (n = 36). Controls were intact animals (in which RST innervation is provided by the ansa; n = 6) and denervated ones (n = 6). At 66 +/- 2 days (mean +/- SE) after neurotization, during quiet breathing, inspiratory electromyographic activity and isometric contraction force were observed in all reinnervated RST muscles (n = 24). During maximal inspiratory effort, electromyographic activity and force increased. In animals reinnervated by the C4 root alone, forces (46.22 +/- 7.8 g) were significantly higher than in intact animals (10.83 +/- 5.0 g). Retrograde labeling proved the phrenic origin of the neurotization. Electromyography of the diaphragm was recorded. We conclude that in rabbits, neurotization of a strap muscle by 1 or 2 roots of the phrenic nerve allows inspiratory contraction, even during quiet breathing. Such inspiratory activity is not observed in sternothyroid muscles of intact animals innervated by the ansa hypoglossi.     

Eye movements during active head turning with different vestibular and cervical input

Eye movements were measured in 15 volunteers during vestibulo-ocular reflex (VOR), cervico-ocular reflex with the head fixed from the ceiling (passive COR), during voluntary stabilization of the head in space while the trunk was moved sinusoidally (active COR) and active head movements with and without additional vestibular or cervical stimuli. The subjects were sitting with eyes covered on a rotating chair swinging sinusoidally at 40 degrees peak to peak amplitude at 0.05, 0.1 and 0.2 Hz. The saccadic activity during passive COR is below the VOR and increases slightly during active COR. During voluntary head movements it shows a marked increase and is further activated if cervical or vestibular stimuli are added. The amplitudes of eye shifts of passive and active COR are not different. During active head movements and more with additional cervical or vestibular input, they increase significantly. The phase of the maximum eye shifts to head position is anticompensatory during passive COR and compensatory during VOR. The phase lead of about 45 degrees during active head movements is less during active COR but is larger with additional cervical and vestibular stimuli reaching 90 degrees.     

Active head turning and correlated cerebral potentials. Experimental and clinical aspects

Fast voluntary horizontal head movements (n = 400, maximum acceleration 8,500 deg/sec2) were recorded together with surface EEG over pre- and post-central regions in 30 healthy volunteers while they were gazing at a head-fixed target in darkness. Artifacts of mechanical, myogenic and oculomotor origin could be precluded. Selective averaging of the fastest movements revealed a biphasic cortical potential. Median latency of its onset was 123.5 msec, of its first peak 189 msec, of the second peak 373 msec, with amplitudes ranging around 5.7 microV. Similar recordings in patients with uni- or bilateral vestibular nerve lesions demonstrated that strong stimulation of the joint vestibular and somatosensory (neck afferent) input facilitated characteristically related EEG activity: side differences of vestibular input could be measured on this level of the CNS, i.e. measured on the cortical level as additional information to the commonly used vestibulo-oculomotor response; patients with early, bilateral loss of vestibular functions showed a specific long-term adaptation of their related EEC activity. We conclude that clinical studies of this kind might aid in diagnosis of vertigo and related phenomena.     

A reexamination of "neck reflex" eye movements in the rabbit.

Horizontal eye movements of rabbits were recorded during sinusoidal oscillation (15-40 degrees, pk-pk; 0.1-8 Hz) and step displacement of the body in yaw about a fixed head. Modulated, slow-phase eye movements followed all frequencies of stimulus with relatively invariant amplitudes (2-4 degrees). Saccadic movements, up to 17 degrees, accompanied all frequencies of oscillation and particularly step displacements. Saccadic amplitude was unrelated to measurable characteristics of the stimuli but was a function of arousal. The latency of any eye movement was a minimum of 80 msec. It is concluded that none of the observed eye movements provide stabilization during head movements but are evidence of the contribution of neck information to general mechanisms of whole body orientation.     

Efficacy of physical therapy on cervical muscle activity and on body posture in school-age mouth breathing children

INTRODUCTION: The mouth breathing resulting from nasal obstruction has been highly incident, mostly as a consequence of allergic rhinitis. In children, such condition is more concerned because it causes alteration during their development, which may generate deformities. OBJECTIVE: To evaluate the efficacy of a program of combined postural exercise and breathing, on the cervical muscles and body posture in school-age mouth breathing children. MATERIALS AND METHODS: Nineteen mouth breathing children, mean age of 10.6 years, both genders, were recruited either from a public school or from a speech-therapy service. The evaluation procedures were electromyographic recordings from the sternocleidomastoid (SCM), sub-occipitals (SOC) and upper trapezius (UT) muscles and computerized photographic analysis pre and post-treatment. The subjects were submitted to a 12-week of a Physical Therapy Program (PTP) consisted by (a) muscular stretching and strengthening exercises using a Swiss ball combined to (b) naso-diaphragmatic re-education. RESULTS: There was a significant reduction (p<0.05) in the electrical activity on the assessed muscles during quiet position (5, 19 and 7.1% to 3, 2 and 10.3% for SCM, SOC and UT, respectively) and aligned posture (7, 19 and 8% to 4, 9 and 2.6% for SCM, SOC and UT, respectively) after treatment. Improvement in the postural deviation, especially reduction in forward head posture and abducted scapula were demonstrated in the computerized photographic analysis. CONCLUSION: A combination of postural and breathing exercises was effective in restoring muscle imbalances and posture in a group of school-age mouth breathing children, as measured by changes in electrical activity and positional data.     

Angioneurotic edemas of the upper aerodigestive tract after ACE-inhibitor treatment

There are rare cases in which inhibitors of the angiotensin-converting enzyme can cause an angioneurotic edema of the upper aerodigestive tract. The pathomechanism of this side effect depends on an interaction of the drug with hormones regulating vascular permeability, such as the kallikrein kinin system and the prostaglandin system. Angioedema is characterized by subcutaneous or submucosal swellings, which usually affect the lips, soft palate, tongue and larynx. Pathomechanisms, differential diagnosis and treatment of ACE-inhibitor-induced edema of the upper aerodigestive tract are described in three case reports.     

Synchrony of laryngeal muscle activity in persons with vocal tremor

OBJECTIVE: To determine if the tremor activity in laryngeal muscles is synchronous, which would indicate a single central source of tremor. DESIGN: Six persons with vocal tremor participated in this study. Laryngeal muscle activity was recorded from 2 intrinsic and 2 extrinsic laryngeal muscles during production of a sustained \i\ sound. Correlations were computed between electromyographic activity in pairs of laryngeal muscles to measure the degree to which electromyographic activity in one muscle was synchronous with electromyographic activity in another laryngeal muscle. In addition, correlations were computed between each of the 4 laryngeal muscles and the voice signal to determine which muscle had activity that was most highly related to amplitude modulations in the voice. Multiple samples from each subject were analyzed to obtain measures of the consistency and strength of the correlations. RESULTS: In most subjects, the bursts of electromyographic activity in one muscle were not consistently related to tremor activity in other affected muscles. Half the subjects exhibited moderate to strong correlations between thyroarytenoid muscle activity and the amplitude of the voice signal. Although the thyroarytenoid and cricothyroid muscles were always active during sustained phonation, half of the subjects did not activate either the thyrohyoid or the sternothyroid muscle during this task. CONCLUSIONS: The results of this study did not support the hypothesis that essential voice tremor is generated by a single central oscillator. Differences in the presence and timing of modulations in laryngeal muscle activity, as described in this study, may reflect clinically in the variable regularity and severity of vocal tremor.     

Comparison of upper and lower lip muscle activity between stutterers and fluent speakers

OBJECTIVE: There is a widespread clinical view that stuttering is associated with high levels of muscles activity. The proposal of this research was to compare stutterers and fluent speakers with respect to the electromyographic activity of the upper and lower lip muscles. METHODS: Ten individuals who stutter and 10 fluent speakers (control group) paired by gender and age were studied (mean age: 13.4 years). Groups were defined by the speech sample analysis of the ABFW-Language Test. A K6-I EMG (Myo-tronics Co., Seattle, WA, USA) with double disposable silver electrodes (Duotrodes, Myo-tronics Co., Seattle, WA) being used in order to analyze lip muscle activity. The clinical conditions investigated were movements during speech, orofacial non-speech tasks, and rest. Electromyographic data were normalized by lip pursing activity. The non-parametric Mann-Whitney test was used for the comparison of speech fluency profile, and the Student t-test for independent samples for group comparison regarding electromyographic data. RESULTS: There was a statistically significant difference between groups regarding speech fluency profile and upper lip activity in the following conditions: lip lateralization to the right and to the left and rest before exercises (P<0.05). There was no significant difference between groups regarding lower lip activity (P>0.05). CONCLUSION: The EMG activity of the upper lip muscle in the group with stuttering was significantly lower than in the control group in some of the clinical conditions analyzed. There was no significant difference between groups regarding the lower lip muscle. The subjects who stutter did not present higher levels of muscle activity in lip muscles than fluent speakers.