Contraction Of Orbicularis Oculi Research Articles

Marin-Amat Syndrome: More Than Meets the Eye.

A 52-year-old man complained of right eye closure whenever eating. He had experienced a right-sided Bell's palsy approximately before 12 months. An examination showed unilateral eye closure on jaw opening or lateral jaw movements, related to active contraction of the entire orbicularis oculi muscle, in addition to ipsilateral hemifacial spasm (Video 1). Marin-Amat syndrome is an acquired synkinesis occurring most frequently after Bell's palsy and is the opposite of the more common Marcus Gunn phenomenon, in which there is eyelid retraction on jaw opening or horizontal movement. It is sometimes erroneously termed an “inverse” Marcus Gunn, although this is a congenital condition in which there is inhibition, and resulting ptosis, of the levator palpebrae muscle on mouth opening, rather than the active contraction of orbicularis oculi seen in Marin-Amat syndrome. Botulinum toxin to the orbicularis oculi muscle, otherwise generally ineffective in the Marcus Gunn phenomenon, can therefore be therapeutic.

They Look but Do Not See—Gaze‐Evoked Eyelid Spasm

They Look but Do Not See—<scp>Gaze‐Evoked</scp> Eyelid Spasm

Effect of Direct Glare on Orbicularis Oculi and Trapezius During Computer Reading.

Unfavorable visual conditions during computer work may affect development of both eyestrain and musculoskeletal pain in the neck and shoulder area. The aim of the study was to investigate how direct glare affects symptom development, muscle activity, and muscle blood flow in m. orbicularis oculi and m. trapezius during reading on a computer screen. Fifteen healthy young adults with normal binocular vision read text on a computer screen at an optimized computer workplace, 30 minutes with glare exposure and 30 minutes with appropriate lighting. Postural angles were continuously registered. Development of eye symptoms and musculoskeletal pain in the neck and shoulder area were recorded using VAS scales. Muscle activity and muscle blood flow were measured continuously using electromyography and photoplethysmography, respectively. Glare exposure resulted in significantly more pronounced eye pain, increased orbicularis muscle activity, and increased trapezius blood flow compared to reading with appropriate lighting. There were no significant differences in posture between the two light conditions. There were also significant associations between orbicularis oculi activity and both trapezius blood flow and neck pain during both conditions. Results from the current study show that direct glare conditions cause increased eyestrain and orbicularis oculi contraction during reading on a computer screen. This study also indicates that exposure to direct glare affects the trapezius muscle, possibly by an interaction between the visual system, sympathetic nervous system, and head-stabilizing muscles. In addition, there were associations between the use of orbicularis oculi, trapezius blood flow, and development of neck pain independent of the lighting.

Síndrome de Marin-Amat y Marcus-Gunn invertido. Presentación de 2 casos de sincinesia facial

Marin-Amat's syndrome is a rare associated movement, wherein contraction of orbicularis oculi is brought about by opening of the jaw in association with aberrant regeneration of facial nerve. This is the opposite of the Marcus-Gunn phenomenon; hence it has also been called Inverted Marcus-Gunn Phenomenon. Moreover in this case the opened the mouth or moved the jaw, the eye would close. This phenomenon is congenital and the closure of the eye is due to inhibition of the levator palpebrae superioris. We present two cases, one acquired after the surgery of tuberculosus cervical adenitis and other congenital with reference to the presentation, course and treatment. This entity is rare in children, with few reported cases, although probably will be found more frequently if looked for carefully. The diagnosis is clinical and does not require additional tests, although EMG may be useful to demonstrate the synkinesis.

Single‐fiber EMG with a concentric needle electrode: Validation in myasthenia gravis

We performed a retrospective study to validate whether a disposable concentric needle electrode (CNE) can be used in place of a single-fiber (SF) electrode for jitter measurements in myasthenia gravis (MG). Normal values for voluntary contraction of orbicularis oculi (OO) and extensor digitorum communis (EDC) were collected from 20 healthy subjects. The method was validated by a retrospective analysis of 56 consecutive MG patients, the "gold standard" being a positive acetylcholine receptor (AChR) antibody titer at the time of the electrophysiological (electromyography) study and the clinical diagnosis. Receiver operating characteristic (ROC) curves were constructed to define maximal sensitivity and specificity of the technique. The sensitivity was 96.4% (95% confidence interval 87.5%-99.6%), with no false-positive results, similar to traditional SF EMG and confirming that the disposable CNE is a justifiable alternative.

Differentiating between reflex and spontaneous blinks using simultaneous recording of the orbicularis oculi electromyogram and the electro-oculogram in startle research

The present study documents the differences between reflex and spontaneous blinks by recording the vertical electro-oculogram (EOG) along with the orbicularis oculi electromyogram (OO-EMG). EOG and OO-EMG were applied without fixation of the head in 15 freely moving children during an auditory startle experiment. Results revealed that the easily-recorded EOG shows the same relationships between orbicularis oculi contraction and velocity of lid movement in startle blinks as the head-constraining methods, e.g. the magnetic search coil, used in previous studies. The OO-EMG onset occurred before the EOG onset in most reflex blinks while no such pattern occurred for spontaneous blinks. In comparison with spontaneous blinks, reflex blinks showed a shorter duration between onset and peak and between onset and offset in OO-EMG and EOG. In addition, reflex blinks showed greater OO-EMG activity and smaller EOG-recorded lid movements compared with spontaneous blinks. Simultaneous recording of OO-EMG and EOG can distinguish reflex from spontaneous blinks and lid saccades in populations, e.g. children, that cannot tolerate head restraint and in experiments permitting or requiring movement.

Bilateral centrotemporal spikes triggered by blinking: an unusual form of sensory input with related cortical EEG activity

Objective: To investigate the morphology, scalp topography and temporal relationship with orbicularis oculi muscle contraction of bilateral blink related spikes (BRS) in a 7-year-old boy with chromosomopathy, mild mental retardation and left spontaneous centrotemporal spikes (SS).Methods: The patient underwent video-polygraphic recordings with off-line analysis of SS and BRS by means of spike-averaging and orbicularis oculi contraction-locked averaging techniques respectively. EEG activity related to reflex blinking (evoked by glabellar tapping) was also studied.Results: SS and BRS presented the same morphology, characterised by four peaks (P1, N1, P2, N2). SS were located over the left centroparietal regions, while BRS were placed over both left and right centrotemporoparietal regions and constantly followed the contraction of orbicularis oculi with overlapping peak latencies over C3 and C4 electrodes (P1 72 ms; N1 115 ms; P2 164 ms; N2 236 ms). Reflex blinking evoked a small waveform with the same features as BRS.Conclusions: Our findings suggest that both involuntary and reflex blinking can act as a form of sensory stimulation probably engaging similar nervous pathways and cortical sources in generating EEG abnormalities: the trigeminal system.

Electromyographic features of levator palpebrae superioris and orbicularis oculi muscles in blepharospasm.

Electromyographic (EMG) recording was performed synchronously from the levator palpebrae superioris (LP) and the orbicularis oculi (OO) muscles in 28 patients referred to us for treatment of blepharospasm with botulinum A toxin. At the time of this study, 19 patients were under the treatment with botulinum, four started treatment shortly after the EMG recording and five patients had not yet been treated. Based on the EMG patterns, we were able to classify five major groups of abnormalities. Group 1 (blepharospasm): consisted of 10 patients with dystonic discharges limited to OO, normal LP tonic activity, intact reciprocal inhibition between LP and OO and dense bursts of action potentials with high amplitude preceding the return of LP tonic activity, i.e. 'postinhibition potentiation' of LP, brought about by a brief contraction of OO. Group 2 (combined dystonic activities of LP and OO): seven patients belonged to this group. The EMG recording revealed alternating tremulous discharges in both LP and OO muscles, and short intervals of co-contractions due to moderately disturbed reciprocal inhibition. Group 3 (combination of blepharospasm, LP motor impersistence): the EMG patterns, observed in three patients, were characterized by a gradual cessation of LP activity, followed by a brief contraction of OO, which facilitated the return of LP activity, resulting in opening of the eyes. The EMG recordings, thus, revealed the crucial, beneficial role of postinhibition potentiation as a compensatory mechanism in this type of eyelid movement disorder. The EMG patterns were also characterized by short or prolonged periods of dystonic discharges limited to the OO muscles. Group 4 (combination of blepharospasm, involuntary LP inhibition): this group consisted of four patients. In addition to episodes of dystonic activities of OO, the EMG also showed some periods of involuntary inhibition of LP without any concomitant activities of OO. Two patients also exhibited a failure of inhibition of OO muscle activity, following the voluntary contraction of this muscle. The postinhibition potentiation was often not observed. Group 5 (involuntary LP inhibition): consisted of four patients with EMG patterns of involuntary inhibition of LP activity, without any dystonic discharges in OO. The postinhibition potentiation was not observed in this group. The response to the treatment with botulinum toxin was good in the first group and gradually worsened towards the fifth group. Application of botulinum into multiple sites of OO, especially its pretarsal portion, resulted in better response to the treatment in the second and fourth groups.(ABSTRACT TRUNCATED AT 400 WORDS)

Differential effect of at rest eye closure and orbicularis oculi contraction (squinting) on acoustic reflex

Previous eye closure studies have suggested muscle tension is responsible for acoustic reflex (AR) enhancement during light eye closure (A. L. Corcoran, M.Sc. dissertation, University of South‐hampton, England, 1976). AR threshold and magnitude were determined for nine normal hearing adults under counterbalanced conditions: (1) eyes open, (2) lightly closed, and (3) tightly closed (contraction of orbicularis oculi). For a 1‐kHz stimulus a 1.1 dB difference was noted between thresholds for eyes open or lightly closed. Squinting however, resulted in a significant 3.6‐ and 4.7‐dB enhancement over the eyes open and closed conditions, respectively. Broadband noise stimuli resulted in a marked enhancement of 9.8 dB while squinting. All conditions differed significantly for the noise stimuli. AR magnitude, however, did not differ across eye closure conditions for either stimuli. Results are compared with previous data on the effects of visual, tactile, olfactory, and mental tasks [Robinette et al., J. Acoust. Soc. Am. Suppl. 1 64, S107 (1978).]

Waveform patterns of reflex and voluntary contraction of the middle ear muscles

Changes in impedance produced by reflex and voluntary contraction of the middle ear muscles and by Eustachian tube activity were compared among 24 normal subjects. Middle ear (ME) impedance changes were recorded graphically during the following maneuvers: (1) Eustachian tube (ET) activity produced by wet swallowing; (2) the acoustic reflex (AR); (3) orbicularis oculi contraction (OO); (4) voluntary contraction of the middle ear muscles (VCMEM). Biofeedback was used to teach subjects VCMEM. Approximately half the population successfully accomplished VCMEM, but only a few subjects could sustain VCMEM. Six different waveform patterns were identified among impedance changes. Identical waveform patterns were recorded for the AR in all subjects. A distinct difference between impedance changes resulting from ET activity and MEM activity was observed. Results indicate (1) VCMEM can be taught to some individuals using biofeedback; (2) there are distinct differences between waveform patterns produced by MEM activity and ET activity; and (3) differences exist between the type of impedance change resulting from the AR compared to those resulting from both OO and VCMEM.