Electrically induced blink reflex in horses

The electrically induced blink reflex was studied electromyographically in 21 healthy adult, detomidine-sedated horses. Using surface electrodes, the supraorbital nerve was electrically stimulated at the supraorbital foramen. The responses were recorded from the ipsilateral and contralateral orbicularis oculi muscles with concentric needle electrodes inserted in the lateral aspect of the ventral eyelids. Ipsilateral and contralateral recordings were made on successive stimulations of the same side of the face, maintaining a constant stimulus intensity. The electromyographically recorded responses consisted of an early R1 response in the orbicularis oculi muscle ipsilateral to the side of stimulation, a bilateral late response (ipsilateral R2 and contralateral Rc) and a third, R3 response, in the ipsilateral orbicularis oculi muscle. All the responses were polyphasic muscle potentials of variable duration and peak to peak amplitudes. The reflex latency of the R1 response was, as in man, fairly stable. The R2 response showed greater variability both within and between individual horses. The Rc response was recorded in only 13 of the 21 horses and showed a slightly longer latency than the corresponding R2. The R3 response, which is significantly related to pain sensation in man, appeared in 19 horses and showed the greatest variability in latency.     

Animal model explains the origins of the cranial dystonia benign essential blepharospasm

The current study demonstrates that combining two mild alterations to the rat trigeminal reflex blink system reproduces the symptoms of benign essential blepharospasm, a cranial dystonia characterized by uncontrollable spasms of blinking. The first modification, a small striatal dopamine depletion, reduces the tonic inhibition of trigeminal reflex blink circuits. The second alteration, a slight weakening of the lid-closing orbicularis oculi muscle, begins an adaptive increase in the drive on trigeminal sensory-motor blink circuits that initiates blepharospasm. By themselves, neither of these modifications causes spasms of lid closure, but combined, they induce bilateral forceful blinking and spasms of lid closure. A two-factor model based on these rodent experiments may explain the development of benign essential blepharospasm in humans. The first factor, a subclinical loss of striatal dopamine, creates a permissive environment within the trigeminal blink circuits. The second factor, an external ophthalmic insult, precipitates benign essential blepharospasm. This two-factor model may also be applicable to the genesis of other cranial dystonias.     

Meige's syndrome associated with basal ganglia and thalamic functional disorders

Magnetic resonance imaging (MRI) or single positron emission computed tomography (SPECT) or both were performed and the responses of surface electromyography (EMG) were examined in seven cases of Meige's syndrome. MRI or SPECT or both demonstrated lesions of the basal ganglia, the thalamus, or both in five of the cases. Surface EMG revealed abnormal burst discharges in the orbicularis oculi and a failure of reciprocal muscular activity between the frontalis and orbicularis oculi in all the cases. These findings suggest that voluntary motor control and reciprocal activity in the basal ganglia-thalamocortical circuits are impaired in Meige's syndrome. In addition, good responses were seen to clonazepam, tiapride and trihexyphenidyl in these cases. Therefore, we conclude that dopaminergic, cholinergic, and gamma-aminobutyric acid (GABA) ergic imbalances in the disorders of the basal ganglia and thalamus in Meige's syndrome cause control in the excitatory and inhibitory pathways to be lost, resulting in the failure of integration in reciprocal muscular activity and voluntary motor control. This failure subsequently causes the symptoms of Meige's syndrome.     

External patello-tibial transfixation. I: Indications and technique

We have studied the pattern of blood flow and pharmacodynamic profile of mivacurium-induced block at the adductor pollicis and orbicularis oculi muscles. We studied 30 adult patients anaesthetized with fentanyl, thiopentone, nitrous oxide-isoflurane, and mivacurium 0.2 mg kg-1. Neuromuscular transmission was monitored with accelerometry (TOF Guard, Biometer, Denmark). Blood flow was measured at the two muscles with the use of a laser Doppler flowmeter (Laserflo BPM2, Vasamedics, USA). All patients developed 100% neuromuscular block at the adductor pollicis muscle. Mean maximum neuromuscular block at the orbicularis oculi was 96.4 (SD 3.5)% (ns). Onset time, time required for 25% and 75% recovery of the first twitch in the train-of-four (T1), and a train-of-four ratio (T4/T1) of 90% at the orbicularis oculi were respectively, mean 130.4 (SD 28.5) s, 9.1 (3.2) min, 16.2 (3.9) min and 20.2 (4.3) min and were significantly shorter than the corresponding values at the adductor pollicis: 202.7 (37.2) s, 12.9 (3.9) min, 21.1 (5.1) min and 30.8 (7.4) min. For a given T1, there was significantly less train-of-four fade (T4/T1) at the orbicularis oculi than at the adductor pollicis muscle during recovery. Blood flow was comparable at the two muscles before induction of anaesthesia. Thiopentone significantly increased thenar muscle blood flow from 2.9 (1.5) to 12.3 (6.8) ml 100 g-1 min-1, with a further increase to 22.7 (8.0) ml 100 g-1 min-1 after isoflurane (P < 0.001). Blood flow at the orbicularis oculi was not altered by thiopentone or isoflurane and was consistently lower than that at the adductor pollicis muscle. We conclude that the different pharmacodynamic profiles of mivacurium-induced block at the orbicularis oculi and adductor pollicis muscles were not related primarily to a difference in blood flows.     

Electromyographic activity in a distant muscle during simple voluntary movements: an unexpected hand-eye linkage

PURPOSE: Supraspinal sensorimotor maps contain adjacent representations of the hand and face. These experiments were designed to determine whether interactions between the representations could be detected at the periphery. METHODS: Simultaneous EMG recordings were made from orbicularis oculi and wrist flexor during three conditions, with 50 repetitions each: during exposure to an auditory cue; responding to the auditory cue by wrist flexion; and performing a self-paced wrist flexion in the absence of an auditory cue. RESULTS: In 8 of 10 healthy volunteers, the rectified, averaged EMGs showed small but consistent increases in orbicularis oculi activity during wrist flexion in the two tasks involving that movement, but not in the auditory task alone. CONCLUSION: In one or more of the central sensorimotor maps, voluntary activation of the wrist flexor representation is accompanied by liminal activation of a nearby facial representation which projects to the motoneurons of orbicularis oculi.     

The psychophysiology of James Bond: Phasic emotional responses to violent video game events.

The authors examined emotional valence- and arousal-related phasic psychophysiological responses to different violent events in the first-person shooter video game "James Bond 007: NightFire" among 36 young adults. Event-related changes in zygomaticus major, corrugator supercilii, and orbicularis oculi electromyographic (EMG) activity and skin conductance level (SCL) were recorded, and the participants rated their emotions and the trait psychoticism based on the Psychoticism dimension of the Eysenck Personality Questionnaire--Revised, Short Form. Wounding and killing the opponent elicited an increase in SCL and a decrease in zygomatic and orbicularis oculi EMG activity. The decrease in zygomatic and orbicularis oculi activity was less pronounced among high Psychoticism scorers compared with low Psychoticism scorers. The wounding and death of the player's own character (James Bond) elicited an increase in SCL and zygomatic and orbicularis oculi EMG activity and a decrease in corrugator activity. Instead of joy resulting from victory and success, wounding and killing the opponent may elicit high-arousal negative affect (anxiety), with high Psychoticism scorers experiencing less anxiety than low Psychoticism scorers. Although counterintuitive, the wounding and death of the player's own character may increase some aspect of positive emotion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gains and losses of the XII-VII component of the "baby-sitter" procedure: a morphometric analysis

The classic hypoglossal transfer to the facial nerve is invariably followed by complications caused by tongue atrophy. In 1984, Terzis introduced the "baby-sitter" procedure which involved a formal cross-facial procedure, in addition to partial neurectomy of the hypoglossal nerve, and an end-to-side coaptation with the ipsilateral facial nerve. This reported study provides, for the first time, quantification of the number of hypoglossal motor fibers needed to successfully restore eye sphincter function, using an end-to-side coaptation with preservation of the tongue. Thirty adult Sprague-Dawley rats were divided into six groups: control, denervated, perineurial window, 20 percent partial neurectomy (PN), 40 percent PN, and 80 percent PN. The procedure involves interposing a nerve graft (saphenous) between the partially severed XII nerve and the upper zygomatic branch of the facial nerve. Evaluation of the behavioral data (blink reflex) revealed good-to-superb return of the blinking mechanism in the 40 percent group, without significant tongue atrophy. Electrophysiologic data in the 40 percent neurectomy group demonstrated superiority to the other groups. Quantitative axonal morphometry of the coaptation sites and graft, as well as motor end-plates of the orbicularis oculi muscle and tongue showed the 40 percent partial neurectomy group to be the optimal group.     

How fast are feedforward postural adjustments of the abdominal muscles?

Abdominal muscles can be activated during rapid but complex motor responses known as feedforward postural adjustments. Exactly how the latency of feedforward adjustments compares with other responses of varying levels of voluntary input and motoneurone excitability remains unclear. Surface electrodes were placed bilaterally over abdominal muscles and over right anterior deltoid (AD) and orbicularis oculi (OO) muscles in eight healthy volunteers. Latencies were obtained during feedforward postural adjustment, acoustic startle reflex, and voluntary activation (respiratory and nonrespiratory) to soft and startling acoustic stimuli. Results showed voluntary activation was fastest for respiratory tasks during mid- or end-expiration. Voluntary activation was also faster when triggered by startling stimuli compared with soft stimuli. These responses were slower than feedforward postural adjustments in all subjects. Feedforward adjustments were slower than acoustic startle reflexes but were somewhat flexible as their amplitude depended on amplitude of AD activation and therefore matched parameters of the movement task. The latency for feedforward postural adjustments of abdominal muscles suggests organization at a low level of the nervous system with limited central processing to match postural responses to movement demands. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neurons located in the trigeminal sensory complex and the lateral pontine tegmentum project to the oculomotor nucleus in the rabbit

Neurons located in the trigeminal sensory complex (TSC) and the lateral pontine tegmentum (LPT) have been reported to project to both the accessory abducens and the facial nuclei, which innervate the retractor bulbi and orbicularis oculi muscles respectively, in order to control the nictitating membrane (NM) and eyelid defensive reflex. Since muscles innervated by the oculomotor nucleus (OCM) also appear to be involved in this reflex, retrograde and anterograde tracers were used in this study to determine whether there are projections from the TSC and LPT to the OCM in the rabbit. Injections of horseradish peroxidase (HRP) in the OCM nucleus labeled neurons in the LPT surrounding the trigeminal motor nucleus dorsally, laterally and ventrally. Only a few scattered neurons were found in the principal and spinal trigeminal nuclei. Injection of biocytin in the LPT area containing most of the HRP-labeled neurons caused anterograde labeling of fibers that crossed the midline and ascended just dorsal to the contralateral medial lemniscus. A proportion of these fibers coursed in a dorsal direction to enter and terminate within the OCM contralateral to the injection site. The location of the motoneuronal groups innervating the different extraocular muscles was studied by retrograde transport of HRP, and compared with the distribution of biocytin-labeled terminals. It was found that the terminals were located in the superior rectus and the levator palpebrae zone of the nucleus. We discuss the functional significance of this projection for the eyelid and NM response.     

Basal cell adenocarcinoma of the salivary glands: comparison with basal cell adenoma through assessment of cell proliferation, apoptosis, and expression of p53 and bcl-2

Local anesthetics, particularly bupivacaine, are known to be myotoxic to skeletal muscle. Injury is followed by satellite cell mediated regeneration. The eyelid is a common site for the injection of local anesthetics. Due to the complex anatomy of this region and the unique properties of facial musculature compared to limb skeletal muscle, the response of the orbicularis oculi to local injection of bupivacaine was examined to determine the time course of maximum satellite cell activation and division. The lower eyelids of rabbits were injected with two doses of a combination of bupivacaine and hyaluronidase, spaced 18 h apart. To assess the time course of satellite cell division, bromodeoxyuridine (BrdU) was injected immediately or, 1, 2, 3, 6 or 13 days after the second bupivacaine injury. The rabbits were sacrificed 24 h later. The eyelids were prepared for immunohistological examination and morphometric analysis of the presence of CD11-positive monocytes, neutrophils and macrophages, MyoD expression in satellite cells and/or myoblasts, and co-expression of BrdU and the developmental myosin heavy chain isoform. One day after bupivacaine injury of the orbicularis oculi, there was a large influx of CD11-positive cells which gradually decreased over time. Maximum activation of satellite cells, as defined by MyoD expression, occurred 2 and 3 days after the injury. Using double labeling techniques, the peak of BrdU incorporation occurred on day 3 and was identified in developmental myosin co-labeled cells 4 days after injury. The peak of satellite cell activation and division occurred 3 days after bupivacaine induced injury, as demonstrated by both MyoD expression and after pulse labeling with BrdU as identified in double labeled cells positive for BrdU and the developmental myosin heavy chain isoform. The process of regeneration in this muscle extended beyond the duration of this study. Muscle fibers remained small in cross-sectional area and positive for developmental myosin 2 weeks after injury, at a time when the fiber number had reached control, uninjured levels.     

Amygdala stimulation enhances the rat eyeblink reflex through a short-latency mechanism.

Amygdala stimulation was shown to enhance the trisynaptic (fast, R1) component of the electromyogram recorded in the rat orbicularis oculi (oo) muscle, which is responsible for the active force generating eyelid closure. The eyeblink was elicited via direct electrical stimulation of the supraorbital branch of the trigeminal nerve. Possible mechanisms responsible for the effect of amygdala stimulation on the eyeblink reflex were evaluated by measuring the amount of R1 enhancement as a function of the interstimulus interval (ISI) between the onset of amygdala and trigeminal nerve stimulation. Amygdala stimulation produced significant R1 enhancement at ISIs that imply short-latency excitation of the eyeblink circuit by way of a fast-acting neurotransmitter. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Delay of clinical recovery from paralysis induced by atracurium: comparison between orbicularis oculi and adductor pollicis

OBJECTIVE: To compare with train-of-four stimulation the delays of the beginning of the spontaneous recovery of the orbicularis oculi and of the adductor pollicis after profound neuromuscular blockade with atracurium. STUDY DESIGN: Prospective, comparative open study. PATIENTS AND METHODS: Twenty-eight physical class ASA 1 and 2 patients under general anaesthesia (propofol, N2O, fentanyl) and profound neuromuscular blockade with atracurium. Train-of-four stimulation, every 10 s, of the ulnar nerve at the wrist (for assessing by tactile means the response of the adductor pollicis) and of the temporal branch of the facial nerve (for assessing visually the response of the orbicularis oculi). On each site, measurement of the delay between the end of the maintenance of deep neuromuscular blockade (last dose of atracurium) and the beginning of the recovery (first response to train-of-four stimulation). RESULTS: In each case, the recovery of the orbicularis oculi began earlier than the recovery of the adductor pollicis (26 +/- 9 min vs 34 +/- 9 min, P < 0.001). The delays of recovery at each site were strongly correlated (r = 0.87; P < 0.001) but the time lag between the responses varied greatly: 1 to 21 min, mean: 8 +/- 5 min, coefficient of variation: 56.6%. CONCLUSION: The orbicularis oculi should not be monitored alone for assessment of recovery from profound neuromuscular blockade by atracurium, as it predicts poorly the time of the recovery of the adductor pollicis.     

Redraping the inferior orbicularis arc

The surgical technique of redraping of the inferior arc of the orbicularis oculi muscle is used primarily to produce lower lid and midfacial smoothing in patients undergoing aesthetic surgery. The midfacial fat compartments, suborbicularis oculi fat and malar fat, are bound to the orbicularis muscle by the superficial muscular aponeurotic system so that redraping the orbicularis muscle also repositions the midface. Orbicularis arc redraping should be accompanied by lateral canthoplasty to ensure stability to the shape of the eyelid fissure postoperatively. Modifications in orbicularis redraping and canthoplasty technique are necessary in patients with prominent eyes and distensible lower lids. Supraplacement of canthal fixation is needed in patients with prominent eyes, and lid shortening is needed in patients who have distensible lower lids. This technique also can be used in patients undergoing reconstructive surgery for correction of lower lid retraction because of its ability to recruit periorbital skin upward into the lower lid. For more severe cases of lower lid retraction after aesthetic surgery, adjunctive procedures such as spacer implants in the lower lid and periosteal flap canthoplasty can be used together with the orbicularis arc redraping to rehabilitate patients.     

Functional organisation of the facial motor system in man

To investigate human corticobulbar projections, electromyographic responses from orbicularis oculi and orbicularis oris muscles were recorded in 11 healthy subjects after transcranial magnetic stimulation. Selective activation of lower facial motoneurones of one hemisphere was reached with the round coil 4 cm lateral to the vertex on a line to the external auditory meatus with stimulus intensities from 45 to 55% (100% = 1.5 T). The mean latency of the OR muscle was 11.5 +/- 1.77 ms contralaterally. Ipsilateral cortical responses were observed in 5 subjects (45%) at a mean latency of 13.88 +/- 2.17 ms. Corticobulbar innervation may have affected bilateral responses in the lower facial muscles as those persisted even after lidocaine blockade of both supraorbital nerves. The functional importance of ipsilateral projections to the lower facial muscles in man is lower than that of the contralateral projections, as evidenced by the fact that they cannot be observed in all subjects or in all motor units. The influence of the trigeminal sensory afferents was excluded from the study after blockade of both supraorbital nerves.     

Neural mechanisms of the corneal blinking reflex in cats

Neural mechanisms of the blinking reflex elicited by corneal stimulation were analyzed with electrophysiological techniques in the encéphale isolé cat. (1) Mechanical and electrical stimulation elicited two successive responses of the electromyogram of the orbicularis oculi. Neuromuscular unit studies revealed that the same unit was excited twice and that the latencies of both responses corresponded well with the two EMG responses. (2) The late response was easily affected by anoxia and pentobarbital administration, and was also abolished with the slow-wave sleep stage. (3) Both responses were abolished by ipsilateral transection between the inferior colliculus and genu of the facial nerve. (4) Compared with the latencies of the EMG, the sum of the conduction times through the sensory trigeminal nucleus and the facial nucleus corresponded with the latency of the early response. The sum of the conduction times through the reticular formation, added to the former reflex arc, corresponded to the latency of the late response. (5) The reflex pathway of the early response is consistent with a three-neuron arc passing through the sensory trigeminal nucleus and the facial nucleus. The late response may employ a multisynaptic arc passing through the brain stem medial reticular formation between the sensory trigeminal nucleus and the facial nucleus.     

The use and abuse of topical corticosteroids

An atypical case of "Foix-Chavany syndrome", is described. A definite diagnosis could be achieved through an electromyographic and reflessological investigation (jaw reflex, blink reflex, perioral reflex), when a poor clinical history was not helping towards a definite diagnostic conclusion. It is proposed that the diagnosis of "Foix-Chavany syndrome" should not be limited only to classical "facial diplegia of cortical origin" or to "facio-linguo-pharyngo-laryngo-masseter paralysis of cortico-subcortical origin". Considering the great clinical variability of a syndrome with a common anatomical substrate, it is proposed to use the eponym for all syndromes characterized by: 1) a motor deficit in the cephalic district with relative integrity of motor function of the limbs; 2) a dissociation between loss of voluntary motility and preservation of reflex and automatic motility.     

Amplitude and bilateral coherency of facial and jaw-elevator EMG activity as an index of effort during a two-choice serial reaction task

In earlier studies, positive but inconsistent relationships have been reported between mental effort and electromyogram (EMG) amplitude in task-irrelevant limb muscles. In this study, we explored whether facial EMG activity would provide more consistent results. Tonic EMG activity of six different facial and jaw-elevator muscles was bilaterally recorded during a two-choice serial reaction task with paced presentation of auditory or visual signals. In Experiment 1, task load (signal presentation rate) was kept constant for 20 min at the level of the subject's maximal capacity. In Experiment 2, task load was increased in a stepwise fashion over six successive 2-min periods from sub- to supramaximal capacity levels. EMG amplitude and coherency between momentary bilateral amplitude fluctuations were measured. In Experiment 1, EMG amplitude of frontalis, corrugator supercilii, and orbicularis oris inferior showed a strong gradual increase throughout the task period, whereas taks performance remained fairly stable. Orbicularis oculi, zygomaticus major, and temporalis EMG showed a much smaller increase or no increase. In Experiment 2, the first three muscles showed a fairly consistent increase in EMG amplitude with increasing task load. Orbicularis oculi and zygomaticus major were not active until task load became supramaximal. Effects of stimulus modality or laterality were not found in any experiment. These results are consistent with the notion that EMG amplitude of frontalis, corrugator, and orbicularis oris provides a sensitive index of the degree of exerted mental effort.     

Sub-Tenon's anesthesia and orbicularis oculi function

BACKGROUND AND OBJECTIVE: To assess the necessary volume of local anesthetic with added hyaluronidase that must be infiltrated to the sub-Tenon's space to achieve complete eyelid akinesia. PATIENTS AND METHODS: Eighty-five consecutive patients were randomly assigned to two groups, receiving either 5 ml or 7 ml of local anesthetic to the sub-Tenon's space. Each patient was assessed clinically at 5 and 10 minutes for orbicularis oculi function. The anesthetic solution consisted of 5 ml of 2% lidocaine, 5 ml of 0.75% bupivacaine hydrochloride, and 1500 IU of hyaluronidase. A top-up of anesthetic infiltration was given in doses of 2 ml if excessive orbicularis muscle function persisted at 10 ml. Routine phacoemulsification surgery was performed, and, if necessary, a top-up of anesthetic was given on the table. RESULTS: Complete eyelid akinesia was achieved in 7.5% (3 of 40) of the patients in the 5-ml group and in 93.3% (42 of 45) of the patients in the 7-ml group (P < .005). There was no effect for 57.5% (23 of 40) of the patients in the 5-ml group and for 2.2% (1 of 45) of the patients in the 7-ml group. A top-up of anesthetic was given in the anesthetic room to 40 patients, 37 of whom were in the 5-ml group, and a Van Lint block of the facial nerves was necessary for 1 patient from the 5-ml group. An on-the-table top-up of anesthesia was necessary for 3 patients (2 from the 5-ml group, 1 from the 7-ml group). CONCLUSIONS: The addition of hyaluronidase promotes diffusion of sub-Tenon's anesthetic, resulting in effective akinesia of the orbicularis oculi. The infiltration of 7 ml of the anesthetic solution significantly improves the rate of eyelid akinesia.     

Patterns of brain electrical activity during facial signs of emotion in 10-month-old infants.

This study examined electroencephalogram (EEG) asymmetries during the presence of discrete facial signs of emotion. Thirty-five 10-month-old infants were tested in a standard stranger- and mother-approach paradigm that included a brief separation from their mother. Infant facial expression was videotaped, and brain electrical activity from left and right frontal and parietal regions was recorded. The videotapes were coded with two different discrete facial coding systems. Artifact-free periods of EEG were extracted that were coincident with the expression of the emotions of joy, anger, and sadness. The data revealed different patterns of EEG asymmetry depending on the type of facial expression and vocal expression of affect that was observed. Expressions of joy that involved facial actions of both zygomatic and orbicularis oculi were seen more often in response to mother approach, whereas smiles that did not involve the action of orbicularis oculi were seen more often in response to approach of the stranger. The former type of smile was associated with relative left frontal activation, whereas the latter type was associated with right frontal activation. Facial expressions of anger and sadness exhibited in the absence of crying were associated with left frontal activation, whereas these same facial expressions during crying were associated with right frontal activation. These data underscore the usefulness of EEG measures of hemispheric activation in differentiating among emotional states associated with differences in facial and vocalic expressivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Monitoring orbicularis oculi predicts good intubating conditions after vecuronium in children

PURPOSE: The aim of the study was to compare visual estimation of onset of neuromuscular blockade at both the adductor pollicis (AP) and the orbicularis oculi (OO) in children and to determine if monitoring the OO could predict good intubating conditions during vecuronium-induced neuromuscular blockade. METHODS: Thirty ASAI--II children (1.5-9 yr) were studied. Anaesthesia was induced with 6-8 mg.kg-1 thiopentone. The ulnar nerve at the wrist and the temporal branch of the facial nerve were stimulated every 10 sec using train-of-four (TOF) stimuli. Vecuronium, 0.15 mg.kg-1, was administered as a bolus. The responses at both the OO and the AP were evaluated visually. Patients were randomly divided into two groups. In the AP group (n = 15), the trachea was intubated when the AP was completely blocked. In the OO group (n = 15), intubation was performed when the OO was completely blocked. Intubating conditions were scored on a scale of 1 to 4. RESULTS: All the patients had complete blockade at both the orbicularis oculi and the adductor pollicis. In the two group, time from injection of vecuronium to complete neuromuscular blockade was shorter at the orbicularis oculi than at the adductor pollicis, 1.5 +/- 0.5 min vs 2.3 +/- 0.7 min, respectively, (P < 0.05; mean +/- SD) in the AP group, 1.7 +/- 0.3 min vs 2.3 +/- 0.8 min, respectively in the OO group (P < 0.05). Intubating conditions were excellent in all patient except one, where it was rated as good. They did not differ between groups. CONCLUSION: Following administration of 0.15 mg.kg-1 vecuronium in children, monitoring of the OO can detect good intubating conditions 0.7 min earlier than with monitoring of the AP.