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Biomedical subjects

G M Macaluso

Publications and source records attributed to G M Macaluso.

At least 19 recordsLinked to original sources
PubMed2001

Conditioning of heteronymous H reflex in human temporalis muscle by stimulation of perioral afferents.

A heteronymous H reflex in the temporalis muscle can be elicited by selective stimulation of the masseteric nerve. The present study aimed at defining the optimal amplitude of the H reflex to detect inhibitory changes induced by stimulation of the perioral afferents and at providing new information on the control of masticatory muscles. Sixteen healthy volunteers participated in the experiment. A conditioning stimulus (CS) to the perioral skin was applied at various delays before an ipsilateral selective masseteric nerve stimulation (test stimulus: TS) while the subject was clenching the teeth at 25% of the maximal voluntary contraction. Two intensities of CS and TS were employed, high and low. The peak-to-peak amplitude of the H reflex (TS) and the root-mean-square value of the preceding electromyography were measured and the data analyzed by three-way analysis of variance and Tukey's posthoc tests. For both intensities used the heteronymous H reflex in the temporalis muscle was significantly decreased by prior activation of perioral afferents for delays from 5 to 60 ms. With a delay of 5 and 35 ms the preceding EMG level was not changed, while it was reduced at 20 and 60 ms delay. The intensities used to elicit the heteronymous H reflex of the temporalis muscle were appropriate to detect a reduction in motoneuron excitability. The reduction in the H reflex without a change in the preceding EMG at 5 and 35 ms delays could be due to presynaptic inhibition of the masseteric afferents exerted by the ipsilateral perioral afferents.

Adult↗
PubMed2001

Effects of local and remote muscle pain on human jaw reflexes evoked by fast stretches at different clenching levels.

Muscle pain imposes significant changes on natural motor tasks, but the consequences for stretch reflexes are still disputed. The present study examined the jaw reflexes to fast (10 ms) stretches of the mandible in an experimental model with local pain in the masseter muscle and remote pain in the tibialis anterior muscle. The stretch reflexes were elicited in healthy volunteers (n=13) before, during, and after periods with constant levels of experimental pain and while the subjects clenched at 0%, 15%, 30%, and 45% of the maximal voluntary contraction (MVC) levels. Surface electromyography (EMG) was used to record the reflex responses. Pain in the masseter muscle (mean +/- SEM, 3.8+/-0.4 on a 10-cm visual analogue scale), but not in the tibialis anterior muscle (3.4+/-0.3; paired t-test, P=0.318) was associated with significant changes in both prestimulus EMG activity (ANOVA, P=0.002) and in peak-to-peak amplitudes of the stretch reflex (ANOVA, P=0.022). However, when the changes in prestimulus EMG activity were taken into consideration a significant increase in the stretch reflex persisted in the painful muscle at 15% and 30% MVC. Local circuits at the trigeminal level involving the fusimotor system are proposed to mediate a significant part of this modulatory effect.

Adult↗
PubMed2000

Trigemino-facial reflex inhibitory responses in some lower facial muscles.

The effects of electrical trigeminal stimulation on activated facial muscles were studied in 20 normal subjects in order to evaluate whether excitatory or inhibitory responses are present and to investigate whether the reflex organization is similar in all the facial muscles. No inhibition was observed in frontalis, orbicularis oculi, orbicularis oris, and mentalis muscles. By contrast, a clear suppression of electromyographic (EMG) activity (late silent period or SP2) was present in the levator labii superioris, depressor anguli oris, and depressor labii inferioris muscles, with a mean latency ranging from 41.8 to 50.2 ms, and a mean duration ranging from 27.5 to 40.9 ms. An early suppression of EMG activity (early silent period or SP1) was observed, with a latency of 16 to 20 ms and a duration of 10 ms, mainly in inferior perioral muscles. Our findings show a selective trigeminal inhibitory influence upon some specific lower facial muscles.

Adult↗
PubMed1999

Effect of clenching levels on heteronymous H-reflex in human temporalis muscle.

Selective stimulation of the masseteric nerve has been shown to elicit a heteronymous H-reflex in the ipsilateral temporalis muscle during voluntary clenching. However, the relation between the electromyographic (EMG) activity of the temporalis muscle and the amplitude of the H-reflex has not been previously described. In the present study, the hypothesis was tested that there would be a positive relationship between the level of EMG activity and the amplitude of the H-reflex. The direct motor response (M-response) in the masseter muscle and the heteronymous H-reflex in the anterior temporalis muscle were successfully elicited by electrical stimulation of the masseteric nerve in 12 of 13 subjects. A new automatic system was used to control the on-line EMG activity and to trigger the stimulus. In a random order, two series of 20 stimuli were delivered at each of four clenching levels (0, 25, 50, and 75% of maximal voluntary contraction). The analysis showed that both the masseteric M-response and the temporalis H-reflex were reproducible within and between series. The amplitude of the temporalis H-reflex increased significantly at higher clenching levels (ANOVA: P=0.003). Clenching at 50% and 75% of the maximal voluntary contraction caused significantly larger amplitudes of the H-reflex than clenching at 25% of the maximal voluntary contraction; at rest, no H-reflex could be recorded. There was a significant correlation between the background EMG activity in the ipsilateral temporalis muscle and the amplitude of the H-reflex (Pearson: r=0.313, P=0.008). These data indicate that the heteronymous H-reflex can be reliably elicited by means of an automatic system for stimulus delivery and that the amplitude of the H-reflex is dependent on the preceding activity of the motoneuron pool.

Adult↗
PubMed1998

Sleep bruxism is a disorder related to periodic arousals during sleep.

There is evidence that sleep bruxism is an arousal-related phenomenon. In non-REM sleep, transient arousals recur at 20- to 40-second intervals and are organized according to a cyclic alternating pattern. Polysomnographic recordings from six subjects (two females and four males) affected by sleep bruxism (patients) and six healthy age-and gender-matched volunteers without complaints about sleep (controls) were analyzed to: (1) compare the sleep structure of bruxers with that of non-complaining subjects; and (2) investigate the relations between bruxism episodes and transient arousals. Patients and controls showed no significant differences in conventional sleep variables, but bruxers showed a significantly higher number of the transient arousals characterized by EEG desynchronization. Bruxism episodes were equally distributed between non-REM and REM sleep, but were more frequent in stages 1 and 2 (p < 0.0001) than in slow-wave sleep. The great majority of bruxism episodes detected in non-REM sleep (88%) were associated with the cyclic alternating pattern and always occurred during a transient arousal. Heart rate during the bruxism episodes (69.3+/-18.2) was significantly higher (p < 0.0001) than that during the pre-bruxing period (58.1+/-15.9). Almost 80% of all bruxism episodes were associated with jerks at the anterior tibial muscles. The framework of the cyclic alternating pattern offers a unified interpretation for sleep bruxism and arousal-related phenomena.

Adult↗
PubMed1998

Heteronymous H-reflex in temporal muscle motor units.

An electric stimulation of the masseteric nerve elicits a heteronymous H-reflex in the temporal muscle. The characteristics of this reflex response were investigated by analysis of the firing probability changes of single motor units. Eleven healthy subjects participated in the experiments. The heteronymous H-reflex of the temporal muscle was electrically elicited by stimulation of the masseteric nerve at 120% of the intensity needed for the maximal masseteric M-wave. From 8 to 24 motor units were sampled from the temporal muscle of each subject. Peri-stimulus time histograms of motor unit recordings were built with a 0.5-ms bin width. The mean firing probability was calculated for the 20 ms preceding the stimulus. The firing probability was considered increased when it exceeded the mean by 3 standard deviations. Of 104 sampled motor units, 40 motor units showed a significant increase of the firing probability, which lasted 1 ms or less in 29 of them. In 12 out of 16 motor units, a significant increase of firing probability also persisted at a lower stimulation intensity (120% of the threshold needed to elicit a masseteric M wave). These data indicate that: (1) some temporal muscle motor units are modulated by afferents from the masseter muscle, (2) the heteronymous H-reflex has a monosynaptic component, and (3) there might be a more complex than just monosynaptic organization serving the heteronymous temporal H-reflex. For the latter conclusion regarding synaptic wiring, however, PSTH studies like the present one can offer only indirect evidence, and this question could be better studied in animals.

Adult↗
PubMed1998

Are jaw and facial reflexes modulated during clinical or experimental orofacial pain?

A variety of jaw and facial reflexes can be evoked by orofacial mechanical or electrical stimuli. Because of its possible diagnostic utility in the management of pain and dysfunction of the masticatory system, the exteroceptive suppression that can be evoked in the masseter and temporalis muscles has been particularly investigated. A review of the different studies emphasizes the crucial importance of the area stimulated and the type of stimulation used to evoke the reflex. More recent studies have applied the necessary standardization of stimulus intensity, clenching levels, recording procedures, and unbiased interpretation of the reflex components in muscle electromyographic (EMG) activity. Controversial results have been reported regarding the differences in these inhibitory (and excitatory) reflex responses between temporomandibular disorder or headache patients and controls. Even if the absence of a second inhibitory phase in the masseteric EMG activity of the patients is a frequent finding, its sensitivity and specificity as a diagnostic tool for myogenous pain or bruxism remain to be tested. Controlled studies on the duration of the second exteroceptive suppression period in tension-type headache patients could not confirm the initially reported difference between patients and asymptomatic subjects. Studies that involve experimentally induced muscle pain could provide better insight into the characteristics of the afferent fibers and synaptic circuitry that are involved in the jaw and facial reflexes.

Arthralgia↗
PubMed1997

[Gingival hypertrophy due to cyclosporine. A clinico-statistical study in 82 patients].

Eighty-two patients were observed at the Dental Department at Parma University. Seventy-six of them had renal transplant and 6 liver transplant. They were in immunosuppressive therapy with cyclosporina, 42 of them were also in calcium antagonist therapy. Gingival hypertrophy was observed in 52 subjects (63.4%) 25 (30%) patients underwent surgical operation, 6 of them (24%) showed a relapse about 3 months after the first operation. Clinical data were measured in accordance with 5 indicators: the level of oral hygiene, cyclosporinemia, contemporaneous use of calcium antagonist, the duration of therapy and the DMF index. By the results obtained, it's possible to suppose that the gravity of the disease is related to the contemporaneous use of calcioantagonist, but it wasn't highly significant (p < 0.05). The degree of oral hygiene was decidedly in relation to the most severe forms of gingival hyperplasia (grade 2-3), (p < 0.001). No relation was found for the duration of therapy, distribution of the DMF index and the level of drugs in the blood.

Adolescent↗
PubMed1996

The influence of the asymmetric tonic neck reflex on the H-reflex in human temporal muscle.

In contrast to limb muscles, little is known about the role of the asymmetric tonic neck reflex (ATNR) on jaw-elevator muscles. The effect of rotation of the head on the H-reflex in the anterior part of the temporal muscle after masseteric nerve stimulation was evaluated. Eight healthy volunteers (7 males and 1 female, age range 18 to 27 years, mean age 22 years) participated. The masseteric M-response and the masseteric and temporal H-reflexes were elicited by stimulating the masseteric nerve using a monopolar needle technique. The electromyographic activity of the muscles was recorded by surface electrodes. The ATNR was modified by changing position of the head: 30 degrees rotation towards the stimulated side (+N), 30 degrees rotation towards the non-stimulated side (-N) and 0 degree central position (C). The heteronymous temporal H-reflex was elicited at a stimulus intensity of 120% maximal M-response at a frequency of 1 Hz, in random series of 5 to 20 sweeps, up to 30-50 sweeps for each position. On-line averaging was performed. A significant reduction of the H-reflex amplitude was observed in the -N position (p-0.02 paired "t"-test, p = 0.015 Wilcoxon signed rank test), while a significant increase was present in the +N position (p = 0.007 PTT and WSR). Also multivariate analysis yielded a significant influence of head rotation on H-reflex amplitude (p = 0.0032). It can be concluded that the ATNR has a significant influence on the H-reflex of the human temporal muscle.

Adolescent↗
PubMed1995

H-reflexes in masseter and temporalis muscles in man.

In contrast with limb muscles, studies on H-reflexes in the trigeminal system are scarce. The present report aimed at reevaluating the responses obtained in the masseter and temporalis muscles after electrical stimulation of their nerves. Twenty-four subjects participated in the experiments. The reflexes were elicited in the masseter and temporal muscles by monopolar stimulation and recorded using surface electrodes. Stimulation of the masseteric nerve evoked an M-response in the masseter and an H-reflex in both the masseter and the temporal muscles. In contrast with the masseter muscle, where the homonymous H-reflex disappeared at higher stimulation intensities, the heteronymous temporal H-reflex remained and reached a plateau. Simultaneous stimulation of the masseteric and deep temporal nerves resulted in an M-response and an H-reflex in both the masseter and temporal muscles. Increasing stimulus intensitites led to disappearance of the H-reflex in both muscles. The results were compared with those obtained by others on limb muscles. As in these muscles, the presence of heteronymous H-reflexes in the jaw muscles can be used in future studies of motoneuronal excitability.

Adult↗
PubMed1995

The influence of stimulating techniques on the masseteric and temporal M-responses in man.

The direct motor responses obtained in the masseter and temporalis muscles after electrical stimulation of their nerves were evaluated. In 10 individuals, earlier stimulation techniques used to evoke M-responses ('bipolar needle' and 'surface' techniques) were compared with a previously undescribed 'monopolar needle' technique. The monopolar needle technique proved to give more stable stimulating conditions than the earlier techniques. Selective stimulation of the masseteric nerve or simultaneous stimulation of the masseteric and deep temporal nerves were found, depending on the position of the stimulating electrode.

Adult↗
PubMed1995

The influence of the position of surface recording electrodes on the relative uptake of the masseteric and temporal M-responses in man.

The present report aimed at evaluating the influence of recording conditions on the relative uptake of direct motor responses obtained in the masseter and temporalis muscles after electrical stimulation of their nerves, using a monopolar needle technique. In 10 subjects, various surface electromyographic recording set-ups were compared using supramaximal M-responses. Volume-conducted potentials originating from the masseter muscle could be recorded from the neck. For the masseter muscle, the optimal position for the active recording electrode was over the anterior and inferior part of the muscle belly. The configuration of the masseter M-response recorded from various positions over the muscle belly was highly variable both intra- and interindividually. The configuration of the M-response of the anterior part of the temporalis muscle showed less variability.

Action Potentials↗
PubMed1994

Unusual synkinetic movements between facial muscles and respiration in hemifacial spasm.

We describe two cases of hemifacial spasm (HFS) with unusual synkinetic movements between facial muscles and respiratory activity. Patient 1 developed an idiopathic HFS. She underwent microvascular decompression surgery, followed by transitory facial nerve palsy; she recovered but later developed a facial synkinesia characterized by involuntary and forced eyelid closure on spontaneous and deep breathing; the orbicularis oculi muscle was active also when her mouth was open (the so-called Marin-Amat syndrome). Patient 2, 1 year after a peripheral facial nerve palsy (Bell's palsy), developed an HFS together with synkinetic movements between the orbicularis oculi muscle and respiration. In both cases electrophysiological studies showed pathological synkinetic electromyographic activity. An enhanced hyperexcitability of brain stem interneurons and facial motoneurons could be suggested to explain the phenomenon.

Aged↗
PubMed1994

Migrant sensory neuritis associated with AIDS: case report.

We studied an AIDS patient who suffered from numbness, paresthesias and pain in the territories of different non-contiguous cutaneous nerves at different times. A transitory partial loss of touch and pinprick sensibility was also present in the same cutaneous areas. Sensory conduction velocities and SAP amplitudes were normal. The clinical picture was consistent with the Migrant Sensory Neuritis of Wartenberg. This rare neuropathy has never previously been described in patients affected by AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1994

[Temporal muscle fatigue studied via muscle conduction velocity technics and spectral analysis of the electromyographic signal].

We examined 6 normal volunteers (3 males and 3 females, age 26-30). They were requested to clench as hard as they could until they felt pain. The experiment was repeated one hour later. Emg was recorded during the fatiguing exercise and the recovery period. We couldn't determine the muscle conduction velocity, probably because of the anatomy of the temporal muscle. The mean of the power spectrum showed wide variability and proved unsuitable for clinical applications, both for diagnosis and follow-up.

Adult↗
PubMed1994

On the cause of tendon areflexia in the Holmes-Adie syndrome.

A case of Holmes-Adie syndrome was studied clinically and electrophysiologically. A total loss of tendon reflexes was observed in upper and lower limbs. The main electrophysiological finding was a marked increase of the central conduction time after stimulation of peroneal and tibial nerves. Motor evoked potentials in soleus muscle after transcranial magnetic stimulation showed normal threshold and latencies. We suggest that tendon areflexia could be a consequence of a dysfunction of somatosensory large diameter afferent fibres at the spinal level.

Adie Syndrome↗