ABSTRACT Periodic alternating nystagmus has been associated with the instability of the velocity ... more ABSTRACT Periodic alternating nystagmus has been associated with the instability of the velocity storage mechanism, which is known to play an important role in both the vestibulo-oculomotor and the optokinetic systems. In the present study we looked for a possible spinal equivalent to PAN. In 3 PAN patients, the H-reflex amplitude proved to be slightly but significantly influenced by nystagmus direction, in that it was greater when the nystagmus was beating toward the stimulation side. This finding suggests that projections from velocity storage may play a role not only in the ocular motor but also in assisting postural stability through the vestibulo-spinal system.
Bollettino della Società italiana di biologia sperimentale, Jan 30, 1981
A study of VEP was carried out by stimulation with white and red flashes in 20 normal subjects an... more A study of VEP was carried out by stimulation with white and red flashes in 20 normal subjects and 58 patients with definite or possible Multiple Sclerosis (MS). In normal subjects, the VEP obtained with the red flash exhibited a simplified waveform and a significantly higher latency of the III and IV peaks than with the white flash. This is due to the different spectral component of the stimulation, which specifically excites foveal receptors whose fibers have a smaller diameter and therefore a lower conduction velocity. The subjects with definite or probable MS showed average VEP latencies which were significantly higher than those of normal subjects. A comparison of the results obtained with the two types of stimulation demonstrates that the red flash reveals a higher number of modified VEPs, thus pointing out even subclinical impairments of the visual pathways.
Bollettino della Società italiana di biologia sperimentale, 1988
Somatosensory evoked potentials by median nerve stimulation were obtained in 50 healthy subjects ... more Somatosensory evoked potentials by median nerve stimulation were obtained in 50 healthy subjects (aged 15-70 years) with cephalic and non cephalic references. Most parameters were influenced by one or more independent variables (sex, age, arm lengths). The coefficients of the appropriate linear models are reported to compute correct individual normal limits.
Electroencephalography and Clinical Neurophysiology/electromyography and Motor Control, 1998
We studied saccade and smooth pursuit eye movements in 31 patients suffering from myotonic dstrop... more We studied saccade and smooth pursuit eye movements in 31 patients suffering from myotonic dstrophy (MD). On the basis of mean value comparisons, saccades were slower and hypometric and smooth pursuit eye movements performed worse in MD patients than in controls. On an individual basis, saccade duration was prolonged in 67.7%, saccades were hypometric in 19.4%, saccade latency was delayed
Electroencephalography and Clinical Neurophysiology/evoked Potentials Section, 1995
The recovery functions of parietal P14-N20, N20-P27 and frontal P22-N30 amplitudes were assessed ... more The recovery functions of parietal P14-N20, N20-P27 and frontal P22-N30 amplitudes were assessed in 17 healthy controls aged 20–50 years by means of the paired stimulus technique. One unpaired and 4 paired stimuli with interstimulus intervals (ISIs) of 25, 50, 75 and 100 msec were cyclically presented in a single run. Responses to the unpaired stimulus were subtracted off-line from paired stimulus responses. The highest suppression was reached at shorter ISIs for components with shorter latencies. The mean suppression of P22-N30 was influenced by the subject's age, being greater in younger subjects. Normative data are reported.
Electroencephalography and Clinical Neurophysiology, 1988
A vigilance-related index (slow wave index, SW1) representing the relative delta+ theta amplitude... more A vigilance-related index (slow wave index, SW1) representing the relative delta+ theta amplitude of the 1 sec prestimuhis EEG spectrum has been related to latencies and amplitudes of the auditory cortical evoked response (EP) in 12 volunteers. Stimuli were 70 dB SL tone bursts delivered at 10 sec ISI. Four selective averages were obtained for each subject according to the subdivision of the SWI into quartiles. The subjects were divided into 2 groups having individual mean SWI values above or below the group's median SWI. Repeated measures MANOVA showed that N1 latency increased within subjects from the first to the fourth SWI quartile and that it was longer in subjects with high mean SWIs. N1-P2 amplitude decreased within subjects from the first to the fourth SWI quartile, but only in the group with high mean SWI.
The Italian Journal of Neurological Sciences, 1989
The usefulness of multimodal evoked potentials for the diagnosis of Multiple Sclerosis (MS) is es... more The usefulness of multimodal evoked potentials for the diagnosis of Multiple Sclerosis (MS) is established. Our purpose was to try to set of 3 EPs (BAEP, median SEP and trigeminal SEP) in the evaluation of brainstem dysfunction. 53 definite and probable MS patients have been examined; they were allotted to 3 groups according to the duration of the disease. Our results showed that median SEP is the most sensitive investigation, while BAEP and trigeminal SEP were abnormal in a smaller number of cases. The combined use of median and trigeminal SEPs supplied sufficient information on brainstem function, without using the complete set of EPs. No significant relation between EP abnormalities and duration of the disease was found.
Multimodal evoked potentials were studied in 13 patients affected by progressive external ophthal... more Multimodal evoked potentials were studied in 13 patients affected by progressive external ophthalmoplegia with histologically proven mitochondrial myopathy. Progressive external ophthalmoplegia occurred with craniosomatic spreading in all the patients and with a varying degree of nervous and/or other system involvement in most of them. In all but one of the subjects, at least one evoked potential modality was abnormal; 11 of them demonstrated an abnormal visual evoked potential, but this finding might have been influenced by concurrent retinal dysfunction. Abnormalities in brainstem auditory evoked potentials and/or somatosensory evoked potentials, revealing an impairment of central sensory pathways, were detected in 7 subjects, 5 of whom lacked clinical evidence of central nervous system involvement. Thus, evoked potentials represent an useful tool for the detection of subclinical central nervous system involvement in patients affected by progressive external ophthalmoplegia with mitochondrial myopathy.
1. Evaluated 9 10-17 yr olds with developmental reading disability (dyslexia), using checkerboard... more 1. Evaluated 9 10-17 yr olds with developmental reading disability (dyslexia), using checkerboard pattern reversal visual evoked potentials (VEPs). The main experimental variables were: large (0.5 cycles per degree; cpd) and small (2 cpd) checks and 2 reversal ...
ABSTRACT Periodic alternating nystagmus has been associated with the instability of the velocity ... more ABSTRACT Periodic alternating nystagmus has been associated with the instability of the velocity storage mechanism, which is known to play an important role in both the vestibulo-oculomotor and the optokinetic systems. In the present study we looked for a possible spinal equivalent to PAN. In 3 PAN patients, the H-reflex amplitude proved to be slightly but significantly influenced by nystagmus direction, in that it was greater when the nystagmus was beating toward the stimulation side. This finding suggests that projections from velocity storage may play a role not only in the ocular motor but also in assisting postural stability through the vestibulo-spinal system.
Bollettino della Società italiana di biologia sperimentale, Jan 30, 1981
A study of VEP was carried out by stimulation with white and red flashes in 20 normal subjects an... more A study of VEP was carried out by stimulation with white and red flashes in 20 normal subjects and 58 patients with definite or possible Multiple Sclerosis (MS). In normal subjects, the VEP obtained with the red flash exhibited a simplified waveform and a significantly higher latency of the III and IV peaks than with the white flash. This is due to the different spectral component of the stimulation, which specifically excites foveal receptors whose fibers have a smaller diameter and therefore a lower conduction velocity. The subjects with definite or probable MS showed average VEP latencies which were significantly higher than those of normal subjects. A comparison of the results obtained with the two types of stimulation demonstrates that the red flash reveals a higher number of modified VEPs, thus pointing out even subclinical impairments of the visual pathways.
Bollettino della Società italiana di biologia sperimentale, 1988
Somatosensory evoked potentials by median nerve stimulation were obtained in 50 healthy subjects ... more Somatosensory evoked potentials by median nerve stimulation were obtained in 50 healthy subjects (aged 15-70 years) with cephalic and non cephalic references. Most parameters were influenced by one or more independent variables (sex, age, arm lengths). The coefficients of the appropriate linear models are reported to compute correct individual normal limits.
Electroencephalography and Clinical Neurophysiology/electromyography and Motor Control, 1998
We studied saccade and smooth pursuit eye movements in 31 patients suffering from myotonic dstrop... more We studied saccade and smooth pursuit eye movements in 31 patients suffering from myotonic dstrophy (MD). On the basis of mean value comparisons, saccades were slower and hypometric and smooth pursuit eye movements performed worse in MD patients than in controls. On an individual basis, saccade duration was prolonged in 67.7%, saccades were hypometric in 19.4%, saccade latency was delayed
Electroencephalography and Clinical Neurophysiology/evoked Potentials Section, 1995
The recovery functions of parietal P14-N20, N20-P27 and frontal P22-N30 amplitudes were assessed ... more The recovery functions of parietal P14-N20, N20-P27 and frontal P22-N30 amplitudes were assessed in 17 healthy controls aged 20–50 years by means of the paired stimulus technique. One unpaired and 4 paired stimuli with interstimulus intervals (ISIs) of 25, 50, 75 and 100 msec were cyclically presented in a single run. Responses to the unpaired stimulus were subtracted off-line from paired stimulus responses. The highest suppression was reached at shorter ISIs for components with shorter latencies. The mean suppression of P22-N30 was influenced by the subject's age, being greater in younger subjects. Normative data are reported.
Electroencephalography and Clinical Neurophysiology, 1988
A vigilance-related index (slow wave index, SW1) representing the relative delta+ theta amplitude... more A vigilance-related index (slow wave index, SW1) representing the relative delta+ theta amplitude of the 1 sec prestimuhis EEG spectrum has been related to latencies and amplitudes of the auditory cortical evoked response (EP) in 12 volunteers. Stimuli were 70 dB SL tone bursts delivered at 10 sec ISI. Four selective averages were obtained for each subject according to the subdivision of the SWI into quartiles. The subjects were divided into 2 groups having individual mean SWI values above or below the group's median SWI. Repeated measures MANOVA showed that N1 latency increased within subjects from the first to the fourth SWI quartile and that it was longer in subjects with high mean SWIs. N1-P2 amplitude decreased within subjects from the first to the fourth SWI quartile, but only in the group with high mean SWI.
The Italian Journal of Neurological Sciences, 1989
The usefulness of multimodal evoked potentials for the diagnosis of Multiple Sclerosis (MS) is es... more The usefulness of multimodal evoked potentials for the diagnosis of Multiple Sclerosis (MS) is established. Our purpose was to try to set of 3 EPs (BAEP, median SEP and trigeminal SEP) in the evaluation of brainstem dysfunction. 53 definite and probable MS patients have been examined; they were allotted to 3 groups according to the duration of the disease. Our results showed that median SEP is the most sensitive investigation, while BAEP and trigeminal SEP were abnormal in a smaller number of cases. The combined use of median and trigeminal SEPs supplied sufficient information on brainstem function, without using the complete set of EPs. No significant relation between EP abnormalities and duration of the disease was found.
Multimodal evoked potentials were studied in 13 patients affected by progressive external ophthal... more Multimodal evoked potentials were studied in 13 patients affected by progressive external ophthalmoplegia with histologically proven mitochondrial myopathy. Progressive external ophthalmoplegia occurred with craniosomatic spreading in all the patients and with a varying degree of nervous and/or other system involvement in most of them. In all but one of the subjects, at least one evoked potential modality was abnormal; 11 of them demonstrated an abnormal visual evoked potential, but this finding might have been influenced by concurrent retinal dysfunction. Abnormalities in brainstem auditory evoked potentials and/or somatosensory evoked potentials, revealing an impairment of central sensory pathways, were detected in 7 subjects, 5 of whom lacked clinical evidence of central nervous system involvement. Thus, evoked potentials represent an useful tool for the detection of subclinical central nervous system involvement in patients affected by progressive external ophthalmoplegia with mitochondrial myopathy.
1. Evaluated 9 10-17 yr olds with developmental reading disability (dyslexia), using checkerboard... more 1. Evaluated 9 10-17 yr olds with developmental reading disability (dyslexia), using checkerboard pattern reversal visual evoked potentials (VEPs). The main experimental variables were: large (0.5 cycles per degree; cpd) and small (2 cpd) checks and 2 reversal ...
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