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Biomedical subjects

G Pavesi

Publications and source records attributed to G Pavesi.

At least 37 records · Page 2Linked to original sources
PubMed1996

Electromyographic evaluation of the spared serratus anterior after postero-lateral thoracotomy.

Postero-lateral thoracotomy is the standard access in thoracic surgery, and can be carried out dividing or preserving the serratus anterior muscle. This last method, besides its advantages, is still a matter of discussion, in fact traction has been claimed to cause severe muscular damage equal to section. We have studied 20 patients (16 males and 4 females, mean age 63 years), who underwent postero-lateral thoracotomy sparing the serratus anterior, after 6 months from surgery, both clinically and by means of electromyography (EMG), to evaluate the functional status of the spared muscles. In 4 cases (20%) there wasn't any neurogenic damage nor clinical evidence of winging scapula; 3 cases (15%) had medium neurogenic damage. The remaining 13 (65%) cases had a medium neurogenic damage and only one patient showed a winging scapula, neverthless being able to lift the arm to shoulder level. Our data confirmed that retraction during surgery does not damage the serratus anterior, leaving a functionally valid muscle.

Aged↗
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

Motor facilitation during action observation: a magnetic stimulation study.

1. We stimulated the motor cortex of normal subjects (transcranial magnetic stimulation) while they 1) observed an experimenter grasping 3D-objects, 2) looked at the same 3D-objects, 3) observed an experimenter tracing geometrical figures in the air with his arm, and 4) detected the dimming of a light. Motor evoked potentials (MEPs) were recorded from hand muscles. 2. We found that MEPs significantly increased during the conditions in which subjects observed movements. The MEP pattern reflected the pattern of muscle activity recorded when the subjects executed the observed actions. 3. We conclude that in humans there is a system matching action observation and execution. This system resembles the one recently described in the monkey.

Arm↗
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

The role of proprioception in the control of prehension movements: a kinematic study in a peripherally deafferented patient and in normal subjects.

In this study we investigated the role of proprioception in the control of prehension movements, with particular reference to the grasp component. Grasp and transport kinematics were studied in a peripherally deafferented patient and in five healthy subjects. Two experiments were carried out: the prehension experiment and the grasp perturbation experiment. In the prehension experiment both the patient and the control subjects were required to reach and grasp three objects of different size, located at three different distances, both with and without visual feedback. In the grasp perturbation experiment a mechanical perturbation was applied to the fingers during prehension movements, again executed with and without visual feedback. In the prehension experiment temporal parameters of the patient's movements were generally slowed, with greater variability on some measures. However, over the first phase of the movement the pattern of the patient's hand opening and transport acceleration, scaled to object size and distance, was the same as that of controls, both with and without visual feedback. On the contrary, during the final phase of the movement (the finger closure phase and deceleration) the patient's performance differed significantly from the controls. These phases were abnormally lengthened and frequent movement adjustments were observed. In the grasp perturbation experiment the patient was not able to compensate for the perturbations applied to the fingers, even with visual feedback. The data allowed us to investigate also the respective contribution of proprioception and of vision of the hand in the control of prehension. We compared prehension kinematics in two conditions: (a) with visual but no proprioceptive feedback (in the patient) and (b) with proprioceptive but no visual feedback (in the controls). In both experiments proprioceptive control was more efficient than visual control. The results of this study are interpreted in favour of the strict dependence of prehension control on proprioception. The first phase of the movement, however, can be appropriately planned and executed without the necessity of either proprioceptive or visual information about the hand.

Adult↗
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

Hereditary sensory and autonomic neuropathy with ataxia and late onset.

We report two brothers affected by a dominantly inherited form of hereditary sensory and autonomic neuropathy (HSAN), characterized by clinical features of sensory ataxia, and by late onset in the 6th decade. Sural nerve biopsy in the proband showed almost complete loss of myelinated fibers, and relative sparing of unmyelinated fibers. This family showed an atypical presentation of HSAN, which is usually characterized by acrodystrophic manifestations of infantile or juvenile onset. Although a few reports of HSAN presenting with late onset and/or ataxia appeared, this is the first report of a family with dominant HSAN characterized by late onset sensory ataxia.

Aged↗
PubMed1994

Peripheral neuropathy associated with primary Sjögren's syndrome.

Clinical and electrophysiological signs of peripheral neuropathy were found in 10 of 46 patients (21.7%) with primary Sjögren's syndrome, symmetric polyneuropathy in seven (mainly sensory in five, mainly autonomic in two), sensory neuronopathy in two patients, and mononeuropathy multiplex in one patient. Peripheral neuropathy was the presenting manifestation in five patients (10.9%). Onset of the disease after 50 years was significantly more common in the polyneuropathy group (six of seven) than in non-neuropathic patients with primary Sjögren's syndrome (14 of 36; p = 0.034). No other difference in clinical or laboratory variables between neuropathic and non-neuropathic patients with primary Sjogren's syndrome was found. Neurophysiological study showed variable findings predominantly suggesting an axonopathy. Nerve biopsy showed moderate remyelination and regeneration in four patients, and fibre loss, mainly of large size, in three. Necrotising vasculitis was not seen but alterations of the endoneurial microvessels were prominent.

Adult↗
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↗
PubMed1993

Unilateral trismus caused by vertebrobasilar dolichoectasia.

Vertebrobasilar dolichoectasia is a relatively uncommon pathological entity and generally asymptomatic. We report a quite unusual case of unilateral motor trigeminal involvement with trismus, due to VD. Apart from tetanus or local morbid conditions of the mouth, trismus is often attributed to disturbed programming and co-ordination of the masticatory muscles within the mesencephalic nucleus. The possibility of truncal compression of the trigeminal motor root by vertebrobasilar dolichoectasia being responsible for masseter muscle spasm, in analogy with the pathogenetic mechanisms proposed in hemifacial spasm, is proposed as an alternative explanation in the present case.

Aged↗
PubMed1992

Peripheral neuropathy in essential mixed cryoglobulinaemia.

The prevalence of various forms of peripheral neuropathy has not been previously assessed in large series of patients with essential mixed cryoglobulinaemia (EMC). Clinical and electrophysiological signs of peripheral neuropathy were observed in 21 of 37 EMC patients, consisting of polyneuropathy in 19, mononeuropathy or multiple mononeuropathy in eight, and both in six. The various forms of peripheral neuropathy occurred differently in the subgroups of EMC. Isolated polyneuropathy was more common with type II (eight of 10) than type III EMC (two of eight). Multifocal neuropathy, in association with polyneuropathy, was the most common form in type III EMC (five of eight). Patients with peripheral neuropathy and type II EMC were significantly older than type II EMC patients without neuropathy, regarding present age and age of onset of EMC. Patients with peripheral neuropathy and type III EMC tended to have higher values of ESR and IgM than type III EMC patients without neuropathy. Electrophysiological findings and sural nerve biopsy specimens (nine cases) showed prominent axonal changes. Vascular changes included vasculitis and alterations of the endoneurial microvessels in type II and type III EMC. Our findings suggest that distinct pathogenic factors are implicated in the subgroups of cryoglobulinaemic neuropathy, possibly inducing different types of vascular changes underlying polyneuropathy or, respectively, mononeuropathy and multiple mononeuropathy.

Adult↗
PubMed1992

Acute sensory and autonomic neuropathy: possible association with coxsackie B virus infection.

This report describes a 26 year old woman with a Coxsackie B virus infection complicated by an acute pandysautonomic and sensory neuropathy. Electrophysiological studies suggested an axonal neuropathy. A sural nerve biopsy performed early in the disease showed axonal degeneration with a virtual absence of unmyelinated fibres and moderate loss of myelinated fibres, mainly affecting the small fibres; this differs from previous reports. An immune-mediated or direct virus action might explain the pathogenesis of this unusual evolution of a viral infection.

Adult↗
PubMed1992

Presurgical electrophysiological findings in acoustic nerve tumours.

The clinical involvement of the facial nerve is a rare finding among the initial symptoms of acoustic neurinomas. However, compression of the facial nerve is a common intraoperative finding. Blink reflex was recorded in 20 patients affected by cerebellar-pontine angle tumor confirmed at surgery. Recordings were also made of the M-response of the facial nerve from the naso-labial folds. In 6 cases jaw reflex was also recorded. In summary, these electrophysiological studies revealed a facial nerve damage in 13 and a trigeminal nerve dysfunction in 2 out of 18 clinically unaffected patients. The combined study of the 3 tests proved to be useful when the blink reflex showed an isolated R1 delay, that is, in cases in which the level of damage along the trigemino-facial reflex arc cannot be defined by the recording of the blink reflex alone.

Adolescent↗
PubMed1991

Magnetic motor evoked potentials (MEPs) in masseter muscles.

Electromyographic responses of the masseter muscles and orbicularis oris muscles following transcranial magnetic stimulations were recorded with surface and needle electrodes. MEPs in masseter muscles (latency 6.9 +/- 0.71 ms, mean +/- SD) due to activation of controlateral cortico-nuclear connections were evoked by magnetic stimulations at 4 cm laterally to the vertex on the biauricular line. These MEPs were followed bilaterally by a silent period lasting about 20 ms and, less constantly, by a later silent period lasting up to 80 ms. The ipsilateral responses to the same stimuli presented shorter latencies and higher amplitudes and they were ascribed to direct stimulation of the trigeminal nerve, probably its intracisternal portion. Ipsilateral masseter "cortical" MEPs could be elicited only by a lower output setting (70% of the maximum output) of the stimulator. Orbicularis oris MEPs were polyphasic and dispersed with latencies ranging from 7 to 11 ms. In patients with hemispheric or capsular ischemic lesions "cortical" MEPs were absent when stimulating the affected hemisphere and present when stimulating the unaffected one. We suggest that the direct corticomotoneuronal projections for the masseter are mainly crossed.

Adult↗
PubMed1990

Motor-evoked potentials in masseter muscle by electrical and magnetic stimulation in intact alert man.

The electromyographic responses of the masseter after different types of transcranial stimulation were recorded with surface and needle electrodes. Magnetic stimulation at 4 cm lateral to the vertex on the biauricular line elicited MEPs in the contralateral masseter (latency 6.9 ms) due to activation of motor cortex or adjacent elements along the cortico-nuclear pathway. The ipsilateral responses to the same stimuli and to more lateral ones had shorter latencies and were ascribed to direct stimulation of the trigeminal nerve, probably its intracisternal portion. This was also the probable origin of the ipsilateral MEPs after both anodic and cathodic bipolar electrical stimulation at 7 and 11 cm lateral to the vertex on the biauricular line.

Adult↗