Sympathetic nerves bridge the cross-transmission in hemifacial spasm

The pathophysiologic basis of hemifacial spasm is abnormal cross-transmission between facial nerve fibers. The author hypothesized that the demyelinated facial nerve fibers were connected with the sympathetic nerve fibers on the offending artery wall, and thus the latter function as a bridge in the cross-transmission circuit. This hypothesis was tested using a rat model of hemifacial spasm. A facial muscle response was recorded while the offending artery wall was electrically stimulated. The nerve fibers on the offending artery wall were blocked with lidocaine, or the superior cervical ganglion, which innervates the offending artery, was resected, and meanwhile the abnormal muscle response was monitored and analyzed. A waveform was recorded from the facial muscle when the offending artery wall was stimulated, named as “Z-L response”. The latency of Z-L response was different from that of abnormal muscle response. When the nerve fibers on the offending artery wall were blocked by lidocaine, the abnormal muscle response disappeared gradually and recovered in 2 h. The abnormal muscle response disappeared permanently after the sympathetic ganglion was resected. Our findings indicate that cross-transmission between the facial nerve fibers is bridged by the nerve fibers on the offending artery wall, probably sympathetic nerve fibers.     

Relationship between reflex excitability and symptom duration in hemifacial spasm

Changes in excitability and symmetry characteristics have been analyzed with blink reflex recovery curve method applied with dual stimuli at 200, 600 and 1000 ms in patients with hemifacial spasm (HFS), spasm duration shorter than 1 year (HFS 1), spasm duration longer than 8 years (HFS 2), and control group. When compared with controls, while HFS cases with short symptom duration had significant decreases in inhibition at 200 ms in the spasm and healthy sides, those with long symptom duration had this finding only in the spasm side at the 200 ms interval. When HFS groups were compared with each other, in cases with HFS 1, decreased inhibition in the spasm side was significant at 200 and 600 ms, while this was significant only at 200 ms in HFS 2 cases. HFS groups were not found to be different in terms of R2 recovery grade. In conclusion, in cases with HFS, decreased inhibition attributed to facial motor neuron and brain stem interneurons is more predominant on the side of the spasm and this was shown to be present also, to some extent, in the contralateral side. It can be said from our findings that the abnormalities of the blink reflex recovery do not progress in cases with HFS when the symptom duration becomes longer.     

Influence of sensory deprivation and perturbation of trigeminal afferent fibers on corticomotor control of human tongue musculature

Several recent studies with transcranial magnetic stimulation (TMS) have demonstrated changes in motor evoked potentials (MEPs) in human limb muscles following modulation of sensory afferent inputs, but little is known about the regulation of the human tongue motor control. To test the effect of local anesthesia (LA) of the lingual nerve and topical application of capsaicin stimulation on tongue MEPs. Fourteen volunteers participated (21–30 years) in two randomized sessions; before, during a nerve block of the lingual nerve or topical capsaicin application (30 μl 5%) on the tongue, and after anesthesia or pain had subsided. EMG electrodes were placed on the tongue and the first dorsal interosseous (FDI) muscle (control). EMG signals were amplified, filtered (20 Hz–1 kHz), and sampled at 4 kHz (Nicolet, USA). TMS were delivered with a figure-of-eight coil (Magstim 200, UK). Scalp sites at which EMG responses were evoked in the relaxed tongue or FDI at the lowest stimulus strength were determined, i.e., motor threshold (T). MEPs were assessed using stimulus–response curves in steps of 10% T. Eight stimuli were presented at each stimulus level. The proximal hypoglossal nerve was activated by TMS delivered over the parieto-occipital skull distal to the right ear. Eight stimuli were delivered at 50% of maximum stimulator output. ANOVAs were used to analyze latency and peak-to-peak amplitudes. Capsaicin evoked mild pain (2.8±0.5), and a strong burning sensation (6.2±0.4) on 0–10 visual analogue scales. MEP amplitudes in tongue and FDI were not influenced by capsaicin (P>0.44) but by stimulus strength (P<0.001). MEP latencies in tongue (8.9±0.2 ms) and FDI (22.4±0.4 ms) were not affected by capsaicin (P>0.19). Hypoglossal nerve stimulation evoked a short-latency (3.6±0.9 ms) response (mean amplitude 65±9 μV); but was unaffected by capsaicin (P>0.54). LA did not have any effect on FDI MEPs but was associated with a significant facilitation of tongue MEPs at T+50% and T+60% about 50 min after the nerve block in the recovery phase. Also in this condition, the direct motor responses evoked by hypoglossal nerve stimulation remained constant. No direct effect of a strong burning sensation could be shown on peripheral or central corticomotor pathways to the relaxed tongue musculature, however, LA of the lingual nerve (cranial nerve V) seems able to induce a delayed change in corticomotor control of tongue musculature (cranial nerve XII) possibly related to unmasking effects at the cortical level but not completely excluding excitability changes at the brain stem level.     

Cryptogenic hemifacial spasm. A neurophysiological study

Whether hemifacial spasm (HFS) is due to axono-axonal ephaptic transmission or to facial nucleus abnormal hyperexcitability remains controversial. The neurophysiological hallmark of HFS is the delayed response (DR). This response has an indirect pathway and thus a long latency. It is evoked A) as a distant response in muscles innervated by a facial branch other than the one stimulated, and B) in muscles innervated by the branch stimulated. In this work, 99 single all-or-none DRs of 24 cases of cryptogenic HFS were studied by threshold stimulation of a branch, or of the trunk, of the facial nerve. A) Eighty-eight distant DRs were studied. Fifty-four of them were frequently evoked as double discharges (DDs), or sometimes as multiple discharges, with a 3 to 7 ms interval. A collision technique, using paired stimuli, showed that the second discharge of 12 out of 20 DDs was accompanied by a back-wave due to a proximal ectopic re-excitation on the axon, or to the back-firing of an alpha cell (F-response), or to both. F-waves in HFS were more frequent than in normals or in other facial pathologies. B) Eleven DRs were recorded in muscles innervated by the facial branch stimulated. Some of them persisted when, using a stronger stimulus, the same all-or-none potential was also evoked as a direct response. In other cases both the direct response and the DR were evoked with identical stimulation threshold. The direct-indirect response interval of these 11 DRs was shorter than the normal M-F interval. These findings suggest that, in the case of HFS, axons are interconnected by uni- and bidirectional ephapses. Self-sustained repetitive firing in such a group of axons apparently results from re-excitations occurring both at the ephapse site and at the cellular level (F-responses). Spasm develops when several groups fire together. The changing excitability of the alpha cells modulates the importance of the phenomenon.     

Paired transcranial magnetic stimulation in hemifacial spasm

OBJECTIVES: The aim of this study was to investigate the changes in cortical excitability in patients with hemifacial spasm (HFS) in order to examine the physiological state of facial nerve nucleus. METHODS: Nineteen patients with HFS and 13 control subjects were examined at rest. The procedure was repeated during voluntary contraction in 6 of control subjects. By paired transcranial magnetic stimulation, conditioning and test motor evoked potentials (MEP) were recorded from bilateral orbicularis oris muscles at interstimulus intervals (ISI) of 20, 25, 30, 50, 75 and 100 ms. RESULTS: In control subjects at rest, ISI's of 20, 25, 30 ms evealed facilitation of the test MEP and inhibition developed at ISI's of 75 and 100 ms. Test MEP facilitation in the contracting controls and on the symptomatic sides of HFS patients was significantly less than the resting controls. Asymptomatic sides of HFS patients behaved similar to the corresponding symptomatic sides and to the contracting controls, although the values were not statistically significant when compared to the resting controls. CONCLUSION: The lessening of facilitation found in this study can be interpreted as an abnormal finding that reflects the changes in the excitability of facial motoneuronal system in patients with HFS. However it is difficult to exclude the possibility that this finding can occur due to the normal behavior of cortex during voluntary or involuntary contraction.     

Somatosensory evoked blink response in hemifacial spasm and peripheral facial palsy

Somatosensory blink response (SBR) is produced by electrical stimulation of peripheral nerves or skin areas remote from the face. We investigated the presence of SBR in cases with hemifacial spasm (HFS) and peripheral facial palsy (PFP). Fifty-seven cases of HFS, 54 cases of PFP and 39 normal subjects were included in the study. A routine blink reflex study was performed in all subjects. Supramaximal stimulation of the median nerve was given ipsilateral to the either spasm or paralytic side for SBR. Recordings were made at the orbicularis oculi (o.oc) bilaterally and ipsilaterally at the orbicularis oris (o.or) muscles. SBR was elicited in 12 of 39 control subject. Twenty four of 48 HFS cases were SBR positive. Twelve of them had o.or response. An SBR was elicited at the ipsilateral o.oc in 35 of 46 patients with PFP with synkinesia. Twenty-six patients had an SBR at the ipsilateral o.or. In the 13 patients with PFP without synkinesia only 3 people had an SBR. SBR positivity was seen more often in PFP with synkinesia than in cases with HFS. SBR if positive spreads to the lower part of the face in most of cases with HFS and PFP with synkinesia.     

Psychophysiology of spider phobia in 8- to 12-year-old girls

The present investigation focused on late event-related potentials (ERPs) and facial electromyographic (EMG) activity in response to symptom provocation in 8- to 12-year-old spider phobic girls and compared results to those in non-fearful controls. Fourteen patients and 14 controls were presented with phobia-relevant, generally fear-inducing, disgust-inducing and affectively neutral pictures in an EEG/EMG session. ERPs were extracted in the time-windows 340-500 ms (P300) and 550-770 ms (late positive potential, LPP). Relative to controls, phobics showed enhanced amplitudes of P300 and LPP in response to spider pictures. This result is interpreted to reflect motivated attention to emotionally salient stimuli. Moreover, phobics showed enhanced average facial EMG activity of the levator labii and the corrugator supercilii in response to spider pictures, reflecting the negative valence and disgust relevance of spiders. Additionally, spider phobic girls relative to controls showed higher overall disgust proneness and heightened average facial EMG activity in both muscle regions in response to disgust stimuli, possibly revealing a disgust-based origin of spider phobia in children. These aspects should be considered in psychotherapeutic treatment of childhood spider phobia.     

Electrophysiological findings of acute peripheral facial palsy in diabetic and non-diabetic patients

The aim of this study is to investigate the role of diabetes mellitus on the clinical and electrophysiological findings of peripheral facial palsy (PFP), the effect of the diabetes duration and polyneuropathy on the electrophysiological parameters. A total of 32 diabetic and 40 non-diabetic patients with peripheral facial palsy were included. All patients were divided into two subgroups based on the time of electrophysiological examinations: within the first 15 days versus within 16–30 days. Neuropathy symptoms and the results of neurological examinations and electrophysiological findings were recorded. The findings of electroneurography (EnoG), blink reflex (BR) evaluation, and needle electromyography (EMG) indicated statistically significant blink reflex abnormalities in diabetic patients compared to non-diabetics. Delay in the latency was more remarkable in the R2 component than in the R1 (p < 0.001). The delay in the R1 latency was also observed in the non-affected side for diabetic patients. The longer duration of the diabetes caused significant delay on the blink reflex latency on both the affected and non-affected sides for R1 component (p = 0.019, p = 0.041, respectively). In contrary, neither the diabetes duration nor the age of the patients correlated with the clinical severity of facial palsy, fiber loss, fibular nerve compound muscle action potential amplitudes, and the nerve conduction velocities.     

Electric field aspects in hypoglossal nerve stimulation for obstructive sleep apnea: A bilateral electrophysiological evaluation of unilateral electrode configuration changes

Hypoglossal nerve stimulation is an established treatment option for obstructive sleep apnea in selected patients. A unilateral hypoglossal nerve stimulation system was approved a decade ago, yet the physiological effect of unilateral hypoglossal stimulation on bilateral tongue motion remains unclear. This study examined how electrode configuration, stimulation cuff position, or body mass index influenced the contralateral genioglossus electromyography (EMG) signal. Twenty-nine patients underwent three EMG recordings in a polysomnographic setting after being implanted with a unilateral hypoglossal nerve stimulator for at least 6 months. The ratio of EMG signals between the ipsi- and contralateral sides was evaluated. No difference in EMG signals was demonstrated based on electrode configurations, stimulation-cuff position, body-mass-index, or sleep apnea severity, even in patients with right tongue protrusion only. Our findings may be explained by a significant level of cross-innervation and by a smaller and less variable circumferential electric field than expected based on prior biophysical models. A patient's individual anatomy needs to be considered during therapy titration in order to achieve an optimal response.     

Clinical usefulness of magnetic resonance cisternography in patients having hemifacial spasm

To evaluate the usefulness of MR cisternography fourteen patients that had hemifacial spasm and 20 control patients underwent MR cisternography. All the patients with hemifacial spasm had a confirmed vascular compression after surgery. MR cisternography was performed using a 1.5-tesla superconducting MR magnet in which a 3D (dimensional) heavily T2-weighted turbo spin-echo sequence was used. In 34 randomly selected individuals, we retrospectively determined whether MR cisternography images could be used to evaluate symptoms, and what the benefits of obtaining this image was. The results were correlated with the surgical findings. The sensitivity was 100% and the specificity was 94% in all patients having a hemifacial spasm. The offending vessels were the anterior inferior cerebellar artery (AICA) in six patients cases, the posterior inferior cerebellar artery (PICA) in six, both the vertebral artery and PICA in one, and the vertebral artery in one. All the images showed good resolution and contrast, and also showed the exact correlation between the facial nerve and intracranial vessels in the multiplaner image. The findings of neurovascular compression were well correlated with the surgical findings. We believe that high-resolution 3D MR cisternography is a very useful method for evaluating the neurovascular compression in patients that have hemifacial spasm.     

Functional organisation of corticonuclear pathways to motoneurones of lower facial muscles in man

EMG responses were recorded from lower facial muscles (depressor labii inferioris or depressor anguli oris) of 12 normal subjects after magnetic stimulation of the motor cortex. Using a figure-of-eight stimulating coil, the largest responses were obtained from points around 8–10 cm lateral to the vertex. Usually they were bilateral and had the same latency (11–12 ms) on both sides of the face. Patients with complete Bell's palsy had no response in muscles on the same side as the lesion, indicating that the ipsilateral component to cortical stimulation was not the result of recrossing in the periphery of nerve fibres from the contralateral side. Single-unit studies showed that cortical stimulation produced two phases of motoneuronal facilitation: a short-latency (central motor delay from contralateral cortex to the intracranial portion of the facial nerve, 7.6 ms), short-duration (1– to 2-ms duration peak in the post-stimulus time histogram) input, which was more commonly evoked by contralateral than ipsilateral stimulation; and a longer latency (central delay > 15 ms), long-duration input evoked equally well from either hemisphere. The former may represent activity in a predominantly contralateral oligosynaptic corticobulbar pathway; the latter, a polysynaptic indirect (e.g. co-rticotegmento-nuclear) bilateral pathway to lower facial muscles.     

面神经脑池段与其周围血管的MRI重建观测及临床应用

目的　为面神经脑池段与其周围血管是否存在压迫或接触提供形态学诊断依据。 方法　选取采用MRI 3D-FIESTA和3D-TOF序列扫描的检查正常者140例和单侧面肌痉挛患者70例,在MPR重建影像上观测I-CSFN-SV的血管直径、与脑干距离和血管自身角度、夹角及其与面肌痉挛发病率之间的关系。 结果　正常组、面肌痉挛健侧组和面肌痉挛患侧组I-CSFN-SV的血管直径、与脑干距离、血管自身角度、夹角分别为（0.48±0.03）mm、（0.49±0.04）mm、（0.71±0.06）mm和（8.69±0.62）mm、（8.66±0.75）mm、（5.93±0.47）mm,（74.39±2.33）°、（72.66±2.54）°、（48.57±3.28）°和（85.60±3.07）°、（86.75±2.73）°、（88.41±3.76）°,面肌痉挛患侧组与正常组、面肌痉挛健侧组I-CSFN-SV的血管直径、与脑干距离、血管自身角度均有显著性差异（P＜0.05）,夹角无显著性差异（P＞0.05）,且随着I-CSFN-SV与脑干距离的增加则发病率呈下降趋势,血管直径的增加和血管自身角度的减小则发病率呈上升趋势,夹角变化与发病率之间无显著性变化趋势。 结论　I-CSFN-SV的血管直径、与脑干距离和血管自身角度是诊断是否存在压迫或接触的重要诊断指标,血管自身角度越小、血管直径越粗和相交处与脑干距离越近,则越容易出现面肌痉挛病变。     

Primary somatosensory evoked magnetic fields elicited by sacral surface electrical stimulation

To explore the brain response to sacral surface therapeutic electrical stimulation (SSTES) for the treatment of refractory urinary incontinence and frequent micturition, evoked magnetic fields were measured in six healthy males. Electrical stimuli were applied between bilateral surface electrodes over the second through fourth posterior sacral foramens with intensity just below the pain threshold. Somatosensory evoked magnetic fields (SEFs) for the bilateral median (MN) and posterior tibial nerves (PTN) were also measured for the comparison. Sources of the early SEF peaks were superimposed on individual magnetic resonance images. The first peak latency for sacral stimuli, M30, occurred at 30.2 ± 0.8 ms (mean ± standard deviation, N = 6), with shorter latency than those for PTN stimulus (39.3 ± 1.4 ms, N = 12) and longer latency than those for MN stimulus (21.0 ± 0.9 ms, N = 12). The second peak latency for sacral stimuli, M50, occurred at 47.2 ± 2.9 ms (N = 6). Both M30 and M50 peaks showed a single dipole pattern over the vertex in the isofield maps. The equivalent current dipoles of M30 and M50 were both estimated near the medial end of the central sulcus with approximately posterior current direction. These results suggest that the sacral M30 and M50 are responses from the primary somatosensory cortex. The relatively long time lag between the onset and peak of M30 suggests that SSTES directly affects both the cauda equina and cutaneous nerve of the sacral surface.     

Activity of neurons located in the region of the hypoglossal motor nucleus during swallowing in sheep

Summary Extracellular activity of swallowing neurons (SN) in the region of the hypoglossal (XIIth) motor nucleus was studied in sheep anesthetized with halothane. Eighty six SN exhibited a discharge closely linked to swallowing electromyographic (EMG) activity of the geniohyoïd (GH) muscle induced by stimulation of the superior laryngeal nerve. Swallowing activation persisted after motor paralysis, indicating that this activity did not result from sensory feedback. SN were classified into two groups. Group I SN (N = 66) discharged a burst of up to 12 spikes for 50–300 ms during the response of GH. Mean frequencies ranged from 10 to 60 Hz, peak instantaneous frequencies from 10 to 100 Hz. Thirty two SN were antidromically activated by stimulating the XIIth nerve. Mean latencies of antidromic spikes were 2.6 ms and 2.4 ms for SN sending their axons in the medial and lateral branches respectively of XIIth nerve, corresponding to conduction velocities of 50.4 m/s and 53.7 m/s. The other 34 group I SN were located at sites with large antidromic field potentials obscuring the identification of unitary antidromic spikes. Thirty group I SN, 16 antidromically activated and 14 in areas with large field potentials, were histologically located in the XIIth motor nucleus between the transverse planes 1 mm caudal to 2 mm rostral to the obex. Group I SN are likely motoneurons supplying GH and tongue musculature. Group II SN (N = 20) were never antidromically activated by XIIth nerve stimulation, and were all located in the reticular formation adjacent to the lateral edge of the XIIth motor nucleus, particularly in transverse planes within 1 mm of the obex. During swallowing, group II SN exhibited an activation (10–50 spikes) lasting from 100 to 370 ms and generally starting before the onset of GH activity. Mean frequencies ranged from 60 to 200 Hz, and peak instantaneous frequencies from 120 to 400 Hz. Central microstimulation of group II SN evoked in the ipsilateral XIIth nerve a synaptic potential with a latency 0.8 to 1.3 ms longer than that induced by directly stimulating the XIIth motor nucleus. In addition, stimulation of group II SN was also effective in eliciting EMG activity of the contralateral GH. These results suggest that group II SN are interneurons involved in the bilateral activation of GH and tongue muscles.     

Startle responses measured in muscles innervated by facial and trigeminal nerves show common modulation

Electromyographic (EMG) potentials of several head muscles were recorded simultaneously in freely moving rats with chronically implanted electrodes. The startle responses of m. temporalis, m. levator auris, and m. levator labii superior were compared. All muscles showed a parallel decrease in latency and an increase in response elicitability and amplitude with an increase in stimulus intensity. A significant latency difference of about 1 ms existed between m. levator auris and m. temporalis. The shortest latency of the EMG response in m. levator auris was 5.5 ms (110 dB SPL). A common fluctuation in response amplitude and latency was found in simultaneous recordings of muscles innervated by the facial and trigeminal nerve, respectively. This shows a common modulatory input to the startle pathway to the cranial motor nuclei.     

Hemifacial spasm and posterior auricular muscle

We aimed to investigate to which extent posterior auricular muscle (PAM) was affected and whether it contributed to the reflex activity in hemifacial spasm (HFS) patients. 19 HFS patients' spasm activities were recorded from facial muscles. Spasm activity of PAM was recorded synchronously on the symptomatic side in all patients. Lateral spread of blink reflex to orbicularis oris and PAMs were recorded in all but two patients. Botulinum toxin was applied to the PAM with the 14 patients presenting tinnitus, "clicking" or a "ticking" sound on the sane side and other positive auricular symptoms. After treatment, there was symptomatic improvement in 9 of 14 patients. The patients presenting with auricular symptoms and showing spasm activity in their PAMs can be thought as a candidate for botulinum toxin treatment scheme.     

Localization and contractile properties of intrinsic longitudinal motor units of the rat tongue

Tongue dysfunction is a hallmark of many human clinical disorders, yet we lack even a rudimentary understanding of tongue neural control. Here, the location and contractile properties of intrinsic longitudinal motor units (MUs) of the rat tongue body are described to provide a foundation for developing and testing theories of tongue motor control. One hundred and sixty-five MUs were studied by microelectrode penetration and stimulation of individual motor axons coursing in the terminal portion of the lateral (retrusor) branch of the hypoglossal nerve in the rat. Uniaxial MU force was recorded by a transducer attached to the protruded tongue tip, and MU location was estimated by electromyographic (EMG) electrodes implanted into the anterior, middle, and posterior portions of the tongue body. All MUs produced retrusive force. MU twitch force ranged from 2-129 mg (mean = 35 mg) and tetanic force ranged from 9-394 mg (mean = 95 mg). MUs reached maximal twitch force in 8-33 ms (mean = 15 ms) and were resistant to fatigue; following 2 min of stimulation, MUs (n = 11) produced 78-131% of initial force. EMG data were collected for 105 MUs. For 65 of these MUs, the EMG response was confined to a single electrode location: for 26 MUs to the anterior, 21 MUs to the middle, and 18 MUs to the posterior portion of the tongue. Of the remaining MUs, EMG responses were observed in two (38/40) or all three (2/40) tongue regions. These data provide the first contractile measures of identified intrinsic tongue body MUs and the first evidence that intrinsic longitudinal MUs are restricted to a portion of tongue length. Localization of MU territory suggests a role for intrinsic MU in the regional control of the mammalian tongue observed during feeding and speech.     

The effect of sleep on reflex genioglossus muscle activation by stimuli of negative airway pressure in humans.

The present study was designed to determine the effect of sleep on reflex pharyngeal dilator muscle activation by stimuli of negative airway pressure in human subjects. Intra-oral bipolar surface electrodes were used to record genioglossus electromyogram (EMG) responses to 500 ms duration pressure stimuli of 0 and -25 cmH2O applied, via a face-mask, in four normal subjects. Stimuli were applied during early inspiration in wakefulness and in periods of non-rapid-eye-movement (non-REM) sleep, defined by electroencephalographic (EEG) criteria. The rectified and integrated EMG responses to repeated interventions were bin averaged for the 0 and -25 cmH2O stimuli applied in wakefulness and sleep. Response latency was defined as the time when the EMG activity significantly increased above prestimulus levels. Response magnitude was quantified as the in ratio of the EMG activity for an 80 ms post-stimulus period to an 80 ms prestimulus period; data from after the subject's voluntary reaction time for tongue protrusion (range, 150-230 ms) were not analysed. Application of the -25 cmH2O stimuli caused genioglossus muscle activation in wakefulness and sleep, but in all subjects response magnitude was reduced in sleep (mean decrease, 61%; range, 52-82%; P = 0.011, Student's paired t test). In addition, response latency was increased in sleep in each subject (mean latency awake, 38 ms; range, 30-50 ms; mean latency asleep, 75 ms; range, 40-110 ms; P = 0.072, Student's paired t test). Application of the -25 cmH2O stimuli caused arousal from sleep on 90% occasions, but in all cases the reflex genioglossus muscle responses (maximum latency, 110 ms) always proceeded any sign of EEG arousal (mean time to arousal, 643 ms; range, 424-760 ms). These results show that non-REM sleep attenuates reflex genioglossus muscle activation by stimuli of negative airway pressure. Attenuation of this reflex by sleep may impair the ability of the upper airway to defend itself from suction collapse by negative pressures generated during inspiration; this may have implications for the pathogenesis of obstructive sleep apnoea.     

A型肉毒毒素对偏侧面肌痉挛患者的疗效及焦虑状况的影响

目的观察A型肉毒素素（BTXA）对偏侧面肌痉挛（HFS）患者痉挛程度的改善和焦虑状况的影响。方法对40例HFS患者进行局部注射BTXA,治疗前和治疗后1个月分别对患者的痉挛程度进行评定,同时采用Zung氏焦虑自评量表（SAS）评价焦虑状况。结果57.5%的HFS患者在BTXA治疗后1个月痉挛完全缓解,32.5%的HFS患者在BTXA治疗后1个月痉挛明显缓解,而且治疗后患者焦虑状况的评分均低于治疗前,差异有统计学意义（P〈0.001）。结论局部注射BTXA可迅速缓解或消除HFS患者肌肉痉挛,改善患者的心理状况。     

Motor unit potential analysis in the cases with hemifacial spasm and postparalytic facial hyperactivity

This study seeks to find an answer to whether the damage caused by the focal demyelinated focus in hemifacial spasm (HFS) causes a deviation from normal in MUP's. The study evaluated MUP parameters of orbicularis oculi (o.oc) and orbicularis oris (o.or) muscles in the total of 76 cases, 41 of whom had a history of peripheral facial paralysis (PFP) and postparalytic facial hyperactivity (PPFHA) and 35 of whom had HFS. Control data was obtained from healthy sides 22 of 76 cases. "t test" and multiple comparisons were used for statistical evaluations. For o.oc muscle; when compared with the normal group, PPFHA group had significantly increased motor unit durations (p < 0.001), phase (p < 0.05), area (p < 0.05), turn (p < 0.05) and polyphasic potential numbers (p < 0.05) and HFS group had significantly increased amplitudes (p < 0.05), area (p < 0.05) and polyphasic potential numbers (p < 0.05). When patients groups were compared for the same muscle, PPFHA group had significantly increased MUP durations (p < 0.001) and number of turns (p < 0.05) as compared to HFS group. When o.or muscle values were compared with the normal group, PPFHA group had significantly increased durations (p < 0.001), phase (p < 0.05), area (p < 0.05) and turn numbers (p < 0.001) and polyphasic potential rates (p < 0.05) and area/amplitude values (p < 0.05), HFS group had significantly increased durations (p < 0.05), phase (p < 0.05), area (p < 0.05) and turn numbers (p < 0.05). When patient groups were compared for the same muscle, MUP duration was significantly increased (p < 0.05) in the PPFHA group as compared to HFS group. In conclusion, with the quantitative method, there is neurogenic involvement in the facial muscles of upper and lower halves in cases of HFS although lesser than PFP cases. This suggests that focal demyelination causes secondary axonal loss at least in some of the cases.