Publications (18)66.33 Total impact
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Article: Theta-Burst Stimulation of the Cerebellum Interferes with Internal Representations of Sensory-Motor Information Related to Eye Movements in Humans
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ABSTRACT: Continuous theta-burst stimulation (cTBS) applied over the cerebellum exerts long-lasting effects by modulating long-term synaptic plasticity, which is thought to be the basis of learning and behavioral adaptation. To investigate the impact of cTBS over the cerebellum on short-term sensory-motor memory, we recorded in two groups of eight healthy subject each the visually guided saccades (VGSs), the memory-guided saccades (MGSs), and the multiple memory-guided saccades (MMGSs), before and after cTBS (cTBS group) or simulated cTBS (control group). In the cTBS group, cTBS determined hypometria of contralateral centrifugal VGSs and worsened the accuracy of MMGS bilaterally. In the control group, no significant differences were found between the two recording sessions. These results indicate that cTBS over the cerebellum causes eye movement effects that last longer than the stimulus duration. The VGS contralateral hypometria suggested that we eventually inhibited the fastigial nucleus on the stimulated side. MMGSs in normal subjects have a better final accuracy with respect to MGSs. Such improvement is due to the availability in MMGSs of the efference copy of the initial reflexive saccade directed toward the same peripheral target, which provides a sensory-motor information that is memorized and then used to improve the accuracy of the subsequent volitional memory-guided saccade. Thus, we hypothesize that cTBS disrupted the capability of the cerebellum to make an internal representation of the memorized sensory-motor information to be used after a short interval for forward control of saccades. KeywordsCerebellum–TMS–TBS–Efference copy–Synaptic plasticity–SaccadesThe Cerebellum 04/2012; 10(4):711-719. · 3.21 Impact Factor -
Article: A Device for the Functional Evaluation of the VOR in Clinical Settings.
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ABSTRACT: We developed the head impulse testing device (HITD) based on an inertial sensing system allowing to investigate the functional performance of the rotational vestibulo-ocular reflex (VOR) by testing its gaze stabilization ability, independently from the subject's visual acuity, in response to head impulses at different head angular accelerations ranging from 2000 to 7000 deg/s(2). HITD was initially tested on 22 normal subjects, and a method to compare the results from a single subject (patient) with those from controls was set up. As a pilot study, we tested the HITD in 39 dizzy patients suffering, non-acutely, from different kinds of vestibular disorders. The results obtained with the HITD were comparable with those from the clinical head impulse test (HIT), but an higher number of abnormalities was detectable by HITD in the central vestibular disorders group. The HITD appears to be a promising tool for detecting abnormal VOR performance while providing information on the functional performance of the rotational VOR, and can provide a valuable assistance to the clinical evaluation of patients with vestibular disorders.Frontiers in neurology. 01/2012; 3:39. -
Article: Check your vestibular skills by reading about the rotational vertebral artery syndrome.
Neurological Sciences 09/2011; 32(6):1239-40. · 1.32 Impact Factor -
Article: A new device to assess static ocular torsion.
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ABSTRACT: In clinical settings, static ocular torsion is assessed by taking a fundus photograph and measuring the angle between a horizontal line and the line connecting the fovea to the head of the optic nerve (centro-cecal axis rotation; CCAR). We developed and tested a system specifically aimed at CCAR measurements, based on low-cost commercial hardware, and that implements an adaptive research algorithm that selects and presents bright dots on a monitor to outline the borders of the blind spot, locate its center, and measure CCAR. We examined 10 healthy subjects who underwent four CCAR measurements to evaluate the reliability of the system and compared our results with those of fundus photographic examination. Our data showed an excyclophoria, with mean ocular torsion of 6.4° in the right and 6.7° in the left eye. These values are in keeping with those in the literature. Moreover, the values of the intraclass correlation coefficients suggest excellent reliability of the technique.Annals of the New York Academy of Sciences 09/2011; 1233:226-30. · 3.15 Impact Factor -
Article: θ-burst stimulation of the cerebellum interferes with internal representations of sensory-motor information related to eye movements in humans.
[show abstract] [hide abstract]
ABSTRACT: Continuous theta-burst stimulation (cTBS) applied over the cerebellum exerts long-lasting effects by modulating long-term synaptic plasticity, which is thought to be the basis of learning and behavioral adaptation. To investigate the impact of cTBS over the cerebellum on short-term sensory-motor memory, we recorded in two groups of eight healthy subject each the visually guided saccades (VGSs), the memory-guided saccades (MGSs), and the multiple memory-guided saccades (MMGSs), before and after cTBS (cTBS group) or simulated cTBS (control group). In the cTBS group, cTBS determined hypometria of contralateral centrifugal VGSs and worsened the accuracy of MMGS bilaterally. In the control group, no significant differences were found between the two recording sessions. These results indicate that cTBS over the cerebellum causes eye movement effects that last longer than the stimulus duration. The VGS contralateral hypometria suggested that we eventually inhibited the fastigial nucleus on the stimulated side. MMGSs in normal subjects have a better final accuracy with respect to MGSs. Such improvement is due to the availability in MMGSs of the efference copy of the initial reflexive saccade directed toward the same peripheral target, which provides a sensory-motor information that is memorized and then used to improve the accuracy of the subsequent volitional memory-guided saccade. Thus, we hypothesize that cTBS disrupted the capability of the cerebellum to make an internal representation of the memorized sensory-motor information to be used after a short interval for forward control of saccades.The Cerebellum 05/2011; 10(4):711-9. · 3.21 Impact Factor -
Article: Gluten sensitivity and the CNS: diagnosis and treatment.
The Lancet Neurology 07/2010; 9(7):653; author reply 654-5. · 23.46 Impact Factor -
Article: A prospective multicentre study to evaluate the consistency of the IHS diagnostic criteria, the usefulness of brain MRI for the diagnosis, follow-up and treatment management, and the outcome after high dosage 6-methylprednisolone therapy, in subjects with Tolosa-Hunt syndrome.
The Journal of Headache and Pain 03/2010; 11(3):285. · 2.43 Impact Factor -
Article: Seizure frequency and sex steroids in women with partial epilepsy on antiepileptic therapy.
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ABSTRACT: Neuroactive sex steroids influence neuron excitability, which is enhanced by estradiol (E2) and decreased by progesterone (Pg). In epilepsy, the production, metabolism, biologic availability, and activity of sex hormones may be affected by seizures themselves or by antiepileptic drugs (AEDs). This cross-sectional observational study was aimed at evaluating the relationships between sex steroids, seizure frequency, and other clinical parameters in women with partial epilepsy (PE) on AED treatments. Serum E2, Pg, sex hormone binding globulin (SHBG) levels, free E2 (fE2), and E2/Pg ratios were determined during the follicular and luteal phases in 72 adult women with PE, and in 30 healthy controls. Hormonal data were correlated with seizure frequency, age, body weight, body mass index (BMI), disease onset and duration, and AED therapies. In patients, E2, fE2, and Pg levels were lower in both ovarian phases, whereas those of SHBG were higher than in controls. No significant changes in hormone levels and in prevalence of anovulatory cycles were observed between patients grouped according to their seizure frequency. However, when compared with those in healthy controls, luteal fE2 and Pg levels were chiefly impaired in women with more frequent seizures, mostly undergoing AED polytherapies, but not in those with absent or rarer seizures. The actual changes in sex steroid levels and E2/Pg ratios did not explain an increased seizure frequency in adult women with AED-treated PE, but patients with more severe disease showed more relevant changes in their sex hormone profile and impaired Pg levels during the luteal phase.Epilepsia 07/2009; 50(8):1920-6. · 3.96 Impact Factor -
Article: Focal epileptic seizures mimicking sleep paralysis.
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ABSTRACT: Sleep paralysis (SP) is a common parasomnia. The diagnostic criteria for SP, as reported in the International Classification of Sleep Disorders, are essentially clinical, as electroencephalography (EEG)-polysomnography (PSG) is not mandatory. We describe a subject whose sleep-related events fulfilled the diagnostic criteria for SP, even though her visual hallucinations were elementary, repetitive and stereotyped, thus differing from those usually reported by patients with SP. Video/EEG-PSG documented the focal epileptic nature of the SP-like episodes.Epilepsy & Behavior 02/2009; 14(3):562-4. · 2.34 Impact Factor -
Article: Comments on: "Tolosa-Hunt syndrome: MR imaging features in 15 patients with 20 episodes of painful ophthalmoplegia" [Eur J Radiol (2008), doi:10.1016/j.ejrad.2007.11.034].
European journal of radiology 12/2008; 69(1):193; author reply 193. · 2.65 Impact Factor -
Article: Multiple memory-guided saccades: movement memory improves the accuracy of memory-guided saccades.
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ABSTRACT: Memory-guided saccades (MGSs) with 3 s memorization delay were recorded in healthy subjects using four different paradigms: two "regular" MGS paradigms with the peripheral target lit for 0.2 s (MGS2) and for 1.8 s (MGS18); a multiple memory-guided saccade (MMGS) paradigm with the target lit for 1.8 s and the instruction to perform a visually guided saccade (VGS) towards it before the MGS; a trained memory-guided saccades (TMGSs) paradigm where the same target was presented so that the subjects should made 10 VGSs before the MGS. The longer target presentation interval (MGS18 paradigm) did not improve the accuracy of MGS. The execution of the VGSs improved the accuracy of the corrective saccades made after the first MGS to drive the eyes closer to the target, and this improvement was independent from the number of the VGSs (there was no difference between the MMGS and the TMGS paradigms). The VGSs provide a template that improves the capability of the corrective saccades to compensate for the residual position error at the end of the first saccade.Progress in brain research 02/2008; 171:425-7. · 3.04 Impact Factor -
Article: The N3 potential compared to sound and galvanic vestibular evoked myogenic potential in healthy subjects and in multiple sclerosis patients.
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ABSTRACT: Both sound (s-) and galvanic (g-) vestibular-evoked myogenic potential (VEMP) enable us to study the saccular pathways. However, the VEMP can be abnormal for non-vestibular factors, such as insufficient activation of the sterno-cleido-mastoid (SCM) muscle or a lesion that involves the accessory nucleus and/or nerve or the SCM muscle. These drawbacks do not affect another technique that evaluates the saccular function: the N3 potential. We recorded both the s- and the g-VEMP and the N3 potential in a group of 31 healthy subjects to establish a reference range. The N3 potential and the s-VEMP were recordable bilaterally from all the subjects, whereas the g-VEMP was undetectable uni- or bilaterally in 7 subjects. The latency and amplitude values of the s-VEMP did not differ from those of the g-VEMP. For all three techniques, the latency and amplitude values from the right and from the left recording and/or stimulation side were the same. We suggest using normative latency and amplitude values based on the mean and ratio of the right- and left-side values. The s-VEMP, the N3 potential and the auditory evoked response (ABR) were compared in 15 subjects suffering from multiple sclerosis. The three techniques detected a similar number of abnormalities, but these abnormalities were not correlated. This suggests that these different techniques should be regarded as complementary in evaluating saccular function.Journal of Vestibular Research 02/2007; 17(1):39-46. · 1.35 Impact Factor -
Article: Binocular control of saccades in idiopathic Parkinson's disease.
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ABSTRACT: We focused on the saccade disconjugate control in idiopathic Parkinson's disease patients. Our data showed that in IPD patients the saccade precision was differently impaired in the two eyes--namely, the disconjugate component was larger than in controls--more for the remembered than for the reflexive task.Annals of the New York Academy of Sciences 05/2005; 1039:588-92. · 3.15 Impact Factor -
Article: Ocular neuromyotonia with both tonic and paroxysmal components due to vascular compression.
Journal of Neurology 03/2005; 252(2):227-9. · 3.47 Impact Factor -
Article: Vestibular evoked myogenic potentials in multiple sclerosis patients.
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ABSTRACT: Vestibular evoked myogenic potentials (VEMPs) are saccular responses to loud acoustic stimuli and are recordable from the sterno-cleido-mastoid muscle ipsilaterally to the stimulated ear. This study aimed to investigate VEMPs in patients suffering from multiple sclerosis (MS), and to compare these findings with both clinical and instrumental data. We recorded VEMPs from 70 MS patients, whose clinical data were retrospectively evaluated for the possible occurrence of: past and current (with respect to VEMP recording) brainstem and/or cerebellar symptoms; current brainstem and/or cerebellar signs. Sixty-five patients underwent brainstem auditory evoked potentials (BAEPs) recording; 63 of the same patients underwent saccadic eye movement recording and subjective visual vertical (SVV) evaluation. VEMPs were abnormal in 31%, BAEPs in 38% and SVV in 21% of the patients. Saccadic eye movements showed a possible brainstem dysfunction in 44.4% of the patients. There was no correlation between the occurrence of abnormalities and the technical means of detection. The same held true for correlations with clinical data, with the exception of the BAEPs; these proved to be more frequently abnormal in patients presenting at neurological examination with brainstem and/or cerebellar signs that were possibly related to the complaint of dizziness. VEMPs should be considered a useful complementary neurophysiological tool for the evaluation of brainstem dysfunction.Clinical Neurophysiology 10/2002; 113(9):1464-9. · 3.41 Impact Factor -
Article: Ocular motor myotonic phenomenon in myotonic dystrophy.
Annals of the New York Academy of Sciences 05/2002; 956:401-4. · 3.15 Impact Factor -
Article: Dizziness and migraine: a causal relationship?
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ABSTRACT: Both migraine and dizziness are very frequent complaints, but the comorbidity of the two disorders is higher than it might be expected to be on the basis of chance alone. This implies a possible causal relationship, but definite diagnostic criteria for migraine-related vertigo are still lacking. Very recent attempts in this direction have shown that migraine may be the third leading cause of vertigo and that migraine-related vertigo may be effectively treated. A review of the literature on this topic, which includes some preliminary data of our own, demonstrates the difficulty in pinpointing migraine-associated vertigo as a clearly-defined entity. However, there is a measure of agreement on a few points: the spells of vertigo occur in patients who habitually suffer from motion sickness, and who have a history of migraine, either without or with aura; the delay between migraine and vertigo onset may be several years; migraine-related vertigo may be described as rotatory and/or as a feeling of unsteadiness, and single spells can occur without any other accompanying symptoms, however, when spells do occur in association with headache, they usually precede it. The vertigo duration may be shorter or longer than that of the migraine aura since it ranges from a few seconds to a continuous condition of unsteadiness.Functional neurology 18(2):97-101. · 1.52 Impact Factor -
Article: Transcranial magnetic stimulation over the cerebellum and eye movements: state of the art.
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ABSTRACT: Transcranial magnetic stimulation (TMS) transiently induces an electrical field in the tissues beneath the area of application, thereby perturbing local cortical activity if applied over the scalp. It can therefore be used to modulate cerebellar function in healthy humans. Even though the role of the cerebellum in eye movement control and adaptation is well known, few experiments have used eye movements to evaluate the effect of TMS over the cerebellum. Single-pulse TMS over the posterior vermis resulted in impaired accuracy of reflexive saccades, acceleration of smooth pursuit, and coordination of saccades and head movements. TMS over the cerebellar hemisphere decreased pursuit gain. Repetitive TMS (rTMS) over the posterior vermis impaired saccade adaptation in a double-step paradigm. Comparing the effects of TMS on different behavioural paradigms could be useful to test cerebellar control of reflexive and voluntary eye movements, and as a probe of cerebellar plasticity. rTMS appears to be especially interesting since its effects outlast the stimulation period and its behavioural consequences can therefore be measured without interfering with the execution of eye movements or with the experimental procedures.Functional neurology 25(3):165-71. · 1.52 Impact Factor
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Institutions
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2002–2012
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Università degli studi di Pavia
- Department of Public Health, Neuroscience, Experimental and Forensic Medicine
Pavia, Lombardy, Italy
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2002–2011
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IRCCS Fondazione Istituto Neurologico Nazionale C. Mondino
- Headache Science Center
Pavia, Lombardy, Italy
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