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F Pisano

Publications and source records attributed to F Pisano.

At least 19 recordsLinked to original sources
PubMed2001

The shortening reaction of forearm muscles: the influence of central set.

OBJECTIVE: The EMG of the forearm muscles shortened by an imposed wrist joint displacement has been studied at different levels and distribution of background muscle activity and with different instructions to the subjects, in order to test the hypothesis that the recorded EMG response (shortening reaction, ShoRe) could be deliberate in origin. METHODS: Ten normal subjects were examined. A torque motor induced 50 degrees wrist extension or flexion at 500 degrees /s. The subjects were relaxed or exerted a 10% maximal voluntary contraction. They were instructed either not to intervene, or to oppose the displacement, or else to assist it. Several trials were repeated at different initial angles. RESULTS: We found a short-latency reflex (SR) in the stretched muscle, be it flexor or extensor, and a later inconstant ShoRe in the antagonist. ShoRe latency was compatible with that of a reaction time (RT), and was not influenced by the initial wrist angle. When subjects assisted the movement, the EMG burst in the shortening muscle was in every respect a RT; when they opposed the movement, the ShoRe disappeared. There was a strict temporal relationship between SR duration and ShoRe latency. CONCLUSIONS: We suggest that the brain would deliberately trigger the ShoRe on recognizing the displacement direction. The occurrence of such activity in the shortened muscle makes the SR to abruptly stop. The temporal relationship between the duration of the SR and onset of the ShoRe can be an expression of the inhibition on the SR burst by the cortical drive to the antagonist muscle being shortened, possibly through the action of spinal inhibitory interneurones. The ShoRe would complete the movement momentarily braked by the SR and redistribute the muscle tone across antagonists, appropriate for the new muscle length.

Adult↗
PubMed2000

Loss of large-diameter spindle afferent fibres is not detrimental to the control of body sway during upright stance: evidence from neuropathy.

Fifteen patients with Charcot-Marie-Tooth type 1A (CMT1A) disease and 46 normal controls were studied. In the patients, leg muscle strength, touch-pressure, vibration and joint position sense were reduced; lower limb tendon reflexes were absent in 12 or markedly decreased. Motor and sensory conduction velocity (CV) of leg nerves was either reduced or not measurable. The Neurological Disability Score and the Neuropathy Score were obtained from clinical and electrophysiological examination, respectively. Tilt of a supporting platform elicited short- (SLR) and medium-latency (MLR) responses to stretch in the foot muscle flexor digitorum brevis (FDB) in controls. In the patients, the former response was absent and the latter delayed. These findings are in keeping with the known loss of large-diameter myelinated fibres, with relative sparing of the smaller fibres. The MLR delay was fully accounted for by the slowed CV of the motor fibres. The MLR afferent time was similar to that in normal subjects. Body sway area (SA) during quiet stance was recorded with eyes open or closed, and with feet apart or together. Under all postural and visual conditions, SA was within normal range in the less severely affected patients, but was moderately increased in the patients with a more severe neuropathy score. Across all patients, no correlation was found between SA and muscle force, motor CV, touch pressure, vibration and joint position sense, considered either separately or as an aggregate. We suggest that: (1) functional integrity of the largest afferent fibres is not necessary for appropriate equilibrium control during quiet stance and (2) any unsteadiness is related to additional functional alterations in smaller fibres, most likely group II spindle afferent fibres.

Adolescent↗
PubMed2000

Quantitative measures of spasticity in post-stroke patients.

OBJECTIVE: Quantitative evaluation of muscle tone in post-stroke patients; correlation of biomechanical indices with conventional clinical scales and neurophysiological measures; characterization of passive and neural components of muscle tone. METHODS: Mechanical stretches of the wrist flexor muscles of 53 post-stroke patients were imposed by means of a torque motor at constant speed. Patients were clinically studied using the Ashworth scale for spasticity and the Medical Research Council score for residual muscle strength. The neurophysiological measures were Hoffmann reflex latency, Hmax/Mmax ratio, stretch reflex threshold speed (SRTS), stretch reflex (SR) latency and area, passive (ISI) and total (TSI) stiffness indices. RESULTS: Hmax/Mmax ratio, SR area, ISI and TSI values were significantly higher in patients, while SRTS was significantly lower. TSI, SRTS and SR area were highly correlated to the Ashworth score. CONCLUSIONS: This EMG-biomechanical technique allows an objective evaluation of changes in muscle tone in post-stroke patients, providing easily measurable, quantitative indices of muscle stiffness. The linear distribution of these measures is particularly indicated for monitoring changes induced by treatment. The apparatus seems suitable to characterize neural stiffness, while difficulties were found in isolating the passive components, because of the occurrence of tonic EMG activity in most spastic patients.

Adult↗
PubMed1999

Somatosensory and motor evoked potentials at different stages of recovery from severe traumatic brain injury.

OBJECTIVE: To detect changes of somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) at different stages of recovery from severe brain injury and to determine whether they can be used to predict late functional outcome. DESIGN: Correlational study on a prospective cohort. SETTING: Brain injury rehabilitation center. PATIENTS: Twenty-seven consecutively sampled patients with severe traumatic brain injury referred to the inpatient intensive rehabilitation unit of primary care in a university-based system. MAIN OUTCOME MEASURES: (1) Glasgow Outcome Scale, Disability Rating Scale, and Functional Independence Measure; (2) SEPs and MEPs from upper limbs (ULs) and lower limbs (LLs). Outcome was assessed at 6 and 12 months after trauma. Correlations were computed with the nonparametric test of Spearman-Rank. RESULTS: Both SEPs and MEPs showed dynamic changes (p < .02 for N20, p < .05 for N30, P40, and N45), with a trend toward a progressive normalization. N30 was more frequently abnormal than N20. SEPs from LLs were more frequently and more persistently abnormal than those from ULs. Clinical and functional outcome was strongly correlated with the degree of abnormality of SEPs from LLs (p < .002), whereas only mild relationships were found with SEPs from ULs. Both SEPs and MEPs showed a high negative predictive value (83% for N30 and 83% for P40), but only SEPs from LLs also had a high positive predictive value (72% for P40). Sensitivity was 88% both for N30 and P40. Specificity was 50% for N30 and 70% for P40). CONCLUSION: SEPs from LLs can be very useful in monitoring the postacute phase of traumatic brain injury and in identifying patients who require further intensive rehabilitation. MEPs may be of questionable value.

Adolescent↗
PubMed1999

Motor neuron disease: usefulness of transcranial magnetic stimulation in improving the diagnosis.

Clinical upper motor neuron (UMN) involvement is sometimes difficult to detect in motor neuron disease (MND). For this reason we performed transcranial magnetic stimulation (TMS) to find out whether this technique may be useful in revealing signs of pyramidal tract impairment. Fifty-five MND patients, clinically divided into 22 amyotrophic lateral sclerosis (ALS), 18 ALS with probable UMN signs (ALS-PUMNS), 10 pure lower motor neuron syndrome (LMNS), and 5 progressive bulbar palsy (PBP), underwent standard TMS, recording from abductor digiti minimi and flexor allucis muscles. Prolongation of cortical motor evoked potential (MEP) latency and central conduction time (CCT) and absent MEP were considered as pathologic. ALS-PUMNS and LMNS patients were clinically reclassified after 1 year. TMS was abnormal in 95.4% of ALS, 72.2% of ALS-PUMNS, 50% of LMNS and 20% of PBP. Correlations between TMS parameters and both clinical signs of UMN involvement and disease severity were highly significant. TMS showed a high sensitivity, but lacked specificity. After 1 year, 11 patients among the ALS-PUMNS group were clinically reclassified as definite ALS: all of them had shown TMS abnormalities at the first examination. In conclusion, TMS provides important diagnostic information for an early prediction of ALS in those MND patients presenting with clinically equivocal UMN impairment.

Adult↗
PubMed1998

Sympathetic skin response in amyotrophic lateral sclerosis.

OBJECTIVES: The aim of our study was to verify the usefulness of the sympathetic skin response (SSR) as an instrument for assessing autonomic involvement in amyotrophic lateral sclerosis (ALS). MATERIAL AND METHODS: - We studied palmar and plantar SSR in 31 patients with ALS (mean age: 58.4+/-9.3 years); 48 age-matched healthy subjects constituted the control group. RESULTS: Palmar SSR was elicitable in all patients, and its latency and amplitude did not significantly differ from that of the controls. Plantar response was evoked in all but 7 patients. The lack of response was significantly related to the functional disability and duration of the disease. CONCLUSIONS: We conclude that SSR, even the plantar response, cannot be considered a useful tool for detecting early autonomic involvement in ALS.

Adult↗
PubMed1996

Quantitative evaluation of normal muscle tone.

Forty-eight normal subjects were evaluated for the purpose of objectively quantifying muscle tone. Flexor carpi radialis and extensor digitorum communis electromyographic (EMG) activity was simultaneously recorded during wrist movements imposed by a torque motor. Each session was subdivided into three steps: (1) measurement of the 'intrinsic stiffness index' (ISI) at 10 degrees/s; (2) measurement of the 'total stiffness index' (TSI) at 500 degrees/s; (3) evaluation of the stretch reflex threshold speed (SRTS). No stretch reflex (SR) was found in about half of the subjects, even at the highest speed. ISI was higher in males (p < 0.001); significant differences in TSI were found between subjects with SR and those without (p < 0.02); no statistical differences in SRTS were found for either age or gender. ISI, TSI and SRTS, appear to be reliable indices of the range of normal muscle tone for its quantitative assessment.

Adult↗
PubMed1996

[Effect of motor neuron density on the curve of motor neuron impoverishment in amyotrophic lateral sclerosis].

We have clinically and electromyographically examined, during a follow-up study, weakened muscles and still clinically normal muscles of 9 patients affected by amyotrophic lateral sclerosis (ALS) and of 3 patients affected by focal benign amyotrophy (FBA). MRC scores corrected with positive semiquantitative evaluations of the number of giant motor unit (MU) action potentials and with negative evaluations of the number of fasciculations and fibrillations potentials have been found to linearly correlate with the percentage of the residual MUs calculated from the mean amplitude and the spike number during maximal voluntary contraction. A main finding is that the loss of MUs slows down in the last 10 months of the disease. It follows that after a phase when the pathological process was accelerated by the toxic effect due to the abnormally high concentration of glutamate released by dead motoneurons, the residual cells because of the decreased motoneuronal density are less exposed to the possible neurotoxic damage.

Action Potentials↗
PubMed1995

SU(4)L

Explore the source record for details and available documents.

Journal Article↗
PubMed1995

Decreased heart rate variability in amyotrophic lateral sclerosis.

Autoregressive spectral analysis of heart rate variability (HRV) was performed in 29 patients with amyotrophic lateral sclerosis (ALS) and 33 age-matched healthy subjects to evaluate the involvement of the autonomic nervous system. HRV analysis provides a means to recognize low (LF) and high (HF) frequency components, respectively mediated by sympathetic and parasympathetic heart control. An increase in the mean heart rate at rest (P < 0.001), a decrease in standard deviation of R-R interval as well as in PNN50 (P < 0.001), and an increase in the LF/HF component ratio (P < 0.01) were found in the ALS patients, indicating a vagal-sympathetic imbalance. These alterations were not related to the clinical features and to the duration of the disease. Our results suggest a subclinical involvement of the autonomic nervous system in ALS, particularly affecting parasympathetic cardiovascular control.

Adult↗
PubMed1995

[Abdominal propriospinal myoclonus of unknown etiology].

We report the case of a 77-year-old woman with a two-year history of abdominal non rhythmic myoclonus. Neurological examination was normal. Bursts of myoclonic activity were recorded from the rectus abdominis muscle and then from the external oblique muscle after a delay of 40 ms. Magnetic resonance imaging of dorsal spine revealed T7-T8 and T9-T10 disc protrusions without root compression. Electroencephalography, back-averaging-EEG, brain computed tomography scan, motor and sensory evoked potentials revealed no abnormality, thus ruling out the possibility that the myoclonic jerks might be of cortical origin. Electromyography of the rectus abdominis and external oblique and of the T7-T8 paraspinal muscles did not show signs of denervation. Therefore a peripheral origin of the myoclonus could be excluded. In our patient the difference in latency of the EMG activity between the external oblique and the rectus abdominis muscles was possibly due to the caudal propagation of the myoclonus by slowly conducting pathways, supporting the hypothesis for its propriospinal origin, even though a known ethiologic factor could not be identified.

Abdominal Muscles↗
PubMed1992

SU(3)

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Journal Article↗
PubMed1992

Deblocking effect of TRH-T in three cases of chronic progressive multifocal neuropathy.

Three cases of acquired demyelinating multifocal neuropathy with persistent conduction blocks are reported. In one of them protyreline tartrate (TRH-T) had an evident deblocking effect; similar but milder effects were seen in the other two cases. The course and consistency of this effect is analyzed on the grounds of clinical and electromyographic findings. The nature of the THR-T responsive conduction block is analysed as a mild variant of CIDP with regard to its occurrence in a late and chronic phase without signs of active immune processes.

Adult↗
PubMed1991

EMG evaluation of motor neuron sprouting in amyotrophic lateral sclerosis.

Collateral sprouting has been evaluated in amyotrophic lateral sclerosis (ALS) patients on the basis of: 1) Motor Unit action potential (M.U.A.P.) parameters evaluated by simultaneous EMG recordings using concentric needle electrodes and surface electrodes and 2) Motor Action Potential (M.A.P.) activated by graded electrical stimulation of nerve and recorded with the same electrodes. Mean values of duration and amplitude were calculated in 40 normal age-matched controls, 42 ALS patients in the early phase of the disease and in 5 muscles of three ALS patients during the whole course of the disease including the last paralytic phase. Percentage of M.U.A.P.s with linked potentials and highest amplitude was also calculated. The study confirms previous suggestions on collateral sprouting occurring in the early, middle and advanced phases of the disease and it shows, at variance with some recent claims, that it fails in the latest phase of paralysis.

Action Potentials↗