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Biomedical subjects

M Fornarelli

Publications and source records attributed to M Fornarelli.

10 recordsLinked to original sources
PubMed1988

Stimulation of motor tracts in multiple sclerosis.

Percutaneous electrical stimulation of the motor cortex was used to evaluate corticospinal conduction to upper-limb motoneurons in 29 patients with multiple sclerosis. Central motor conduction abnormalities were correlated with clinical signs and somatosensory evoked potentials. Muscle responses to cortical stimulation were altered in 20 patients. The most common abnormality was increased central motor conduction time; in two cases the responses to cortical stimulation were absent. Abnormalities were also present in patients with no clinical evidence of corticomotoneuron deficit. Alterations of muscle responses and of somatosensory evoked potentials were usually correlated, but may appear independently. Both testing methods are useful in the study of patients with multiple sclerosis.

Adult↗
PubMed1988

Impairment of masticatory function in hemiplegia.

We studied masseter muscle function in 15 hemiplegic patients. Direct motor responses to stimulation of the masseteric nerve were normal. Voluntary activity at maximum strength was reduced on the paretic side. The jaw jerk was symmetric, but facilitation by teeth clenching showed on the nonparetic side only. Masseter silent periods were ill-defined and prolonged in recordings from the paretic side. The second silent period, but not the first, was reduced in size when the paretic side was stimulated, and showed an increased habituation. Though the masticatory nucleus receives bilateral innervation, the contralateral hemisphere exerts a predominant control on voluntary activity and multisynaptic reflexes.

Adult↗
PubMed1984

Recovery cycle of the masseter inhibitory reflex in man.

The masseter inhibitory reflex from stimulation of the mental nerve has been recorded electromyographically in 10 healthy subjects. The recovery cycle of the two silent periods interrupting the tonic contraction of the masseter muscles have been studied with the paired shock technique. There was a clear dissociation between the recovery of early and late inhibition, the latter being far more affected by a preceding impulse. It is concluded that the two silent periods are mediated by separate neural nets. The differences with the recovery curves of the two components of the blink reflex are discussed.

Adult↗
PubMed1983

Reflex and cortical responses to dental stimuli.

Tooth pulp stimulation may evoke reflex responses in the orbicularis oculi, temporal, masseter and retronuchal muscles, which may to a varying degree contaminate the cortical evoked responses. The use of repetitive stimulation reduces the amplitude of the cortical responses but avoids the onset of the majority of the muscle reflexes. The appearance of a silent period in the temporal muscle is hard to avoid and it alters the signal recorded from S1 for the first 60-70 msec. In the center-posterior leads, more protected from the EMG signal of the temporal muscle, a first negative deflection is recorded at 43 msec in 60% of subjects.

Cerebral Cortex↗
PubMed1983

The limits of tooth pulp evoked potentials for pain quantitation.

Tooth pulp evoked potentials (TPEPs) and subjective evaluation of painful dental stimuli have been recorded in healthy volunteers. The amplitude of TPEPs late components and the subjective rating have been studied in different psychological states, by the expectancy of pain with a placebo and by providing foreknowledge of stimulus timing with self-stimulation. The placebo induced a significant depression of TPEPs and pain sensation. The amplitude of TPEPs evoked by self-delivered stimuli was reduced but the subjective report remained unchanged. These results demonstrate that TPEPs are not a stable correlate of the pain perceived or of the painful input.

Dental Pulp↗
PubMed1982

[Effect of high-frequency percutaneous stimulation on experimental pain].

Ten healthy volunteers were submitted to an experimental pain test performed by electrical stimulation of one tooth, before and after 20 min high-frequency (300 Hz) electrical stimulation, for the purpose of relieving pain, delivered to the lip or to three other somatotopically non related areas. The stimulation of the lip only showed a statistically significant analgesic action. The effect was remarkable (31% of total pain relief) and of the same order of magnitude at any intensity level of the tooth stimulation, the threshold being affected too. It is concluded that a central inhibitory mechanism, activated by large afferents input, should subserve this kind of analgetic procedure.

Adult↗