Effects of Transcranial Ultrasound Stimulation on Trigeminal Blink Reflex Excitability.

Recent evidence indicates that transcranial ultrasound stimulation (TUS) modulates sensorimotor cortex excitability. However, no study has assessed possible TUS effects on the excitability of deeper brain areas, such as the brainstem. In this study, we investigated whether TUS delivered on the substantia nigra, superior colliculus, and nucleus raphe magnus modulates the excitability of trigeminal blink reflex, a reliable neurophysiological technique to assess brainstem functions in humans. The recovery cycle of the trigeminal blink reflex (interstimulus intervals of 250 and 500 ms) was tested before (T0), and 3 (T1) and 30 min (T2) after TUS. The effects of substantia nigra-TUS, superior colliculus-TUS, nucleus raphe magnus-TUS and sham-TUS were assessed in separate and randomized sessions. In the superior colliculus-TUS session, the conditioned R2 area increased at T1 compared with T0, while T2 and T0 values did not differ. Results were independent of the interstimulus intervals tested and were not related to trigeminal blink reflex baseline (T0) excitability. Conversely, the conditioned R2 area was comparable at T0, T1, and T2 in the nucleus raphe magnus-TUS and substantia nigra-TUS sessions. Our findings demonstrate that the excitability of brainstem circuits, as evaluated by testing the recovery cycle of the trigeminal blink reflex, can be increased by TUS. This result may reflect the modulation of inhibitory interneurons within the superior colliculus.

The evolving role of echocardiography in the assessment of patent foramen ovale in patients with left-side thromboembolism.

Patent foramen ovale (PFO) is the most common congenital cardiac abnormality found approximately in 25% of the adult population The pathophysiological role of paradoxical embolization through the PFO in ischemic stroke is well established. "Self-expanding double disk" and, more recently, suture-based "deviceless" systems are used for PFO closure in the setting of secondary prevention after ischemic stroke likely related to paradoxical embolization. Ultrasound plays a significant role in PFO assessment, indication to treatment, intra-procedural guidance, and follow-up for those undergoing PFO closure. Three different techniques are frequently used for these purposes: transesophageal echocardiography, transthoracic echocardiogram, and transcranial Doppler. In this review, advantages and limits of these techniques are discussed in detail to improve our skills in detection and treatment of this important condition by using ultrasound.

Cognitive Performance in Relapsing-Remitting Multiple Sclerosis: At Risk or Impaired?

INTRODUCTION: Since cognitive impairment (CI) occurs on average in 45% of multiple sclerosis (MS) patients, the early detection of patients "at risk" of CI is important in order to promptly apply preventive strategies. The aim of the present study was to investigate the prevalence and risk factors for CI in MS patients using the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) as a screening test. METHODS: During the 1-year period, CI was evaluated in 82 consecutives mild relapsing-remitting MS (EDSS ≤ 3.5) patients. Patients with 1 altered BICAMS test were defined "at risk." Both "at risk" and CI patients underwent an extensive neuropsychological battery. RESULTS: We found that: (i) 23% had CI, (ii), 25% were "at risk" of CI, and (iii) 76% of the "at risk" patients were already impaired at the NP assessment. In particular, the Symbol Digit Modalities Test was the most compromised (70% of "at risk" and 79% of CI patients). Patients with CI had more frequently an EDSS ≥ 2.5 (p = 0.05), lower education (p = 0.05), and relapses in the last 12 months (p = 0.03). CONCLUSIONS: CI is a significant issue in MS and integration of a screening test, such as the SDMT, into routine clinical practice could be of worth to identify "at risk" patients and to promote an early therapeutic intervention.

Short-Term Effects of Focal Muscle Vibration on Motor Recovery After Acute Stroke: A Pilot Randomized Sham-Controlled Study.

Repetitive focal muscle vibration (rMV) is known to promote neural plasticity and long-lasting motor recovery in chronic stroke patients. Those structural and functional changes within the motor network underlying motor recovery occur in the very first hours after stroke. Nonetheless, to our knowledge, no rMV-based studies have been carried out in acute stroke patients so far, and the clinical benefit of rMV in this phase of stroke is yet to be determined. The aim of this randomized double-blind sham-controlled study is to investigate the short-term effect of rMV on motor recovery in acute stroke patients. Out of 22 acute stroke patients, 10 were treated with the rMV (vibration group-VG), while 12 underwent the sham treatment (control group-CG). Both treatments were carried out for 3 consecutive days, starting within 72 h of stroke onset; each daily session consisted of three 10-min treatments (for each treated limb), interspersed with a 1-min interval. rMV was delivered using a specific device (Cro®System, NEMOCO srl, Italy). The transducer was applied perpendicular to the target muscle's belly, near its distal tendon insertion, generating a 0.2-0.5 mm peak-to-peak sinusoidal displacement at a frequency of 100 Hz. All participants also underwent a daily standard rehabilitation program. The study protocol underwent local ethics committee approval (ClinicalTrial.gov NCT03697525) and written informed consent was obtained from all of the participants. With regard to the different pre-treatment clinical statuses, VG patients showed significant clinical improvement with respect to CG-treated patients among the NIHSS (p < 0.001), Fugl-Meyer (p = 0.001), and Motricity Index (p < 0.001) scores. In addition, when the upper and lower limb scales scores were compared between the two groups, VG patients were found to have a better clinical improvement at all the clinical end points. This study provides the first evidence that rMV is able to improve the motor outcome in a cohort of acute stroke patients, regardless of the pretreatment clinical status. Being a safe and well-tolerated intervention, which is easy to perform at the bedside, rMV may represent a valid complementary non-pharmacological therapy to promote motor recovery in acute stroke patients.

Longitudinal Study on Low-Dose Aspirin versus Placebo Administration in Silent Brain Infarcts: The Silence Study.

BACKGROUND: We investigated low-dose aspirin (ASA) efficacy and safety in subjects with silent brain infarcts (SBIs) in preventing new cerebrovascular (CVD) events as well as cognitive impairment. METHODS: We included subjects aged ≥45 years, with at least one SBI and no previous CVD. Subjects were followed up to 4 years assessing CVD and SBI incidence as primary endpoint and as secondary endpoints: (a) cardiovascular and adverse events and (b) cognitive impairment. RESULTS: Thirty-six subjects received ASA while 47 were untreated. Primary endpoint occurred in 9 controls (19.1%) versus 2 (5.6%) in the ASA group (p=0.10). Secondary endpoints did not differ in the two groups. Only baseline leukoaraiosis predicts primary [OR 5.4 (95%CI 1.3-22.9, p=0.022)] and secondary endpoint-a [3.2 (95%CI 1.1-9.6, p=0.040)] occurrence. CONCLUSIONS: These data show an increase of new CVD events in the untreated group. Despite the study limitations, SBI seems to be a negative prognostic factor and ASA preventive treatment might improve SBI prognosis. EU Clinical trial is registered with EudraCT Number: 2005-000996-16; Sponsor Protocol Number: 694/30.06.04.

Neurophysiological correlates of clinical improvement after greater occipital nerve (GON) block in chronic migraine: relevance for chronic migraine pathophysiology.

BACKGROUND: Therapeutic management of Chronic Migraine (CM), often associated with Medication Overuse Headache (MOH), is chiefly empirical, as no biomarker predicting or correlating with clinical efficacy is available to address therapeutic choices. The present study searched for neurophysiological correlates of Greater Occipital Nerve Block (GON-B) effects in CM. METHODS: We recruited 17 CM women, of whom 12 with MOH, and 19 healthy volunteers (HV). Patients had no preventive treatment since at least 3 months. After a 30-day baseline, they received a bilateral betamethasone-lidocaine GON-B of which the therapeutic effect was assessed 1 month later. Habituation of visual evoked potentials (VEP) and intensity dependence of auditory evoked potentials (IDAP) were recorded before and 1 week after the GON-B. RESULTS: At baseline, CM patients had a VEP habituation not different from HV, but a steeper IDAP value than HV (p = 0.01), suggestive of a lower serotonergic tone. GON-B significantly reduced the number of total headache days per month (- 34.9%; p = 0.003). Eight out 17CM patients reversed to episodic migraine and medication overuse resolved in 11 out of 12 patients. One week after the GON-B VEP habituation became lacking respect to baseline (p = 0.01) and to that of HV (p = 0.02) like in episodic migraine, while the IDAP slope significantly flattened (p < 0.0001). GON-B-induced reduction in headache days positively correlated with IDAP slope decrease (rho = 0.51, p = 0.03). CONCLUSIONS: GON-B may be effective in the treatment of CM, with or without MOH. The pre-treatment IDAP increase is compatible with a weak central serotonergic tone, which is strengthened after GON-B, suggesting that serotonergic mechanisms may play a role in CM and its reversion to episodic migraine. Since the degree of post-treatment IDAP decrease is correlated with clinical improvement, IDAP might be potentially useful as an early predictor of GON-B efficacy.

Right-to-left shunt detection sensitivity with air-saline and air-succinil gelatin transcranial Doppler.

BACKGROUND: Air-saline transcranial Doppler is nowadays the first-choice examination to identify right-to-left shunt. To increase right-to-left shunt detection in echocardiography, cardiologists also use air-gelatin mixtures, which are more stable, more echogenic, and easier to be prepared. AIM: We assessed the sensitivity of air-gelatin compared with air-saline for transcranial Doppler right-to-left shunt detection. METHODS: Air-saline transcranial Doppler, during unilateral middle cerebral artery monitoring at rest and after Valsalva maneuver, was performed in patients referred to our neurosonology laboratory for right-to-left shunt detection. The same transcranial Doppler protocol was repeated with air-gelatin. To consider transcranial Doppler positive for cardiac right-to-left shunt, at least one embolic signal had to be detected within 20″ from contrast injection. Later signals were interpreted of pulmonary origin. Trans-thoracic echocardiography was repeated with both air-saline and air-gelatin. RESULTS: A total of 97 patients were enrolled; 46 had negative transcranial Doppler for cardiac right-to-left shunt with both air-saline and air-gelatin; out of these, four patients with air-saline plus two more patients with air-gelatin presented late, isolated microemboli, slightly more numerous with air-gelatin: these were interpreted as pulmonary shunts and confirmed with trans-thoracic echocardiography. In 28 patients with already early positive air-saline transcranial Doppler at rest, air-gelatin induced a marked right-to-left shunt increase, facilitating its visualization at trans-thoracic echocardiography. In 23 patients in whom air-saline transcranial Doppler was negative at rest and positive for cardiac right-to-left shunt only after Valsalva maneuver, air-gelatin was able to reveal shunt also at rest. CONCLUSIONS: Air-gelatin increases right-to-left shunt detection sensitivity with transcranial Doppler in particular at rest, even in patients in whom air-saline mixture fails to identify the shunt. The choice of air-gelatin mixture should be considered for multicentric, clinical, and research trials.

Neuroanatomical, Clinical and Cognitive Correlates of Post-Stroke Dysphagia.

BACKGROUND AND PURPOSE: About half of the dysphagic stroke patients have persistent swallowing dysfunction after 7 days from symptom onset. The aim of the study was to evaluate incidence, prognosis, clinical and neuroradiological correlates of post-stroke dysphagia. METHODS: We prospectively examined consecutive patients with acute ischemic or hemorrhagic stroke. Patients' clinical and neuroradiological data were collected. Swallowing function was assessed by the water swallow test upon admission and after 14 days; patients were then classified as persistent dysphagic, non-persistent dysphagic or non-dysphagic. RESULTS: We recruited 275 patients, 121 of whom were dysphagic upon admission and 254 patients attended follow-up at 14 days; 141 never presented dysphagia, 21 had a non-persistent pattern of dysphagia and 92 had a persistent one. Stroke type, leukoaraiosis degree, previous cognitive impairment and stroke severity upon admission independently predicted the occurrence of dysphagia after stroke and its persistence as well. At receiver operating characteristic (ROC) analysis, the National Institutes of Health Stroke Scale (NIHSS) score of 11.5 was the best predictive value of persistent dysphagia, with a specificity of 90.1% and a sensitivity of 72.4%. CONCLUSION: Stroke severity is an important predictor of a persistent pattern of dysphagia, with a suggested NIHSS cutoff value of ≥12. An independent correlation was observed with leukoaraiosis and with previous cognitive impairment.

The Mozart Effect: A quantitative EEG study.

The aim of this study is to investigate the influence of Mozart's music on brain activity through spectral analysis of the EEG in young healthy adults (Adults), in healthy elderly (Elderly) and in elderly with Mild Cognitive Impairment (MCI). EEG recording was performed at basal rest conditions and after listening to Mozart's K448 or "Fur Elise" Beethoven's sonatas. After listening to Mozart, an increase of alpha band and median frequency index of background alpha rhythm activity (a pattern of brain wave activity linked to memory, cognition and open mind to problem solving) was observed both in Adults and in Elderly. No changes were observed in MCI. After listening to Beethoven, no changes in EEG activity were detected. This results may be representative of the fact that said Mozart's music is able to "activate" neuronal cortical circuits related to attentive and cognitive functions.

A study of migraine characteristics in joint hypermobility syndrome a.k.a. Ehlers-Danlos syndrome, hypermobility type.

Joint hypermobility syndrome (JHS) and Ehlers-Danlos syndrome, hypermobility type (EDS-HT) are two clinically overlapping heritable connective tissue disorders strongly associated with musculoskeletal pain, fatigue and headache. Migraine with or without aura is considered the most common form of headache in JHS/EDS-HT. In this population of chronically ill patients, we investigated whether migraine characteristics were different from those of a control population of migraine patients. The study was carried out on 33 selected JHS/EDS-HT patients, diagnosed according to current criteria. Sixty-six migraine subjects matching age and gender were consecutively selected as controls (MO group) among patients attending our Headache Clinic. JHS/EDS-HT and MO were screened for a series of headache characteristics, such as frequency, intensity, age of onset, level of disability, use of rescue and prophylactic medications. Differences between the two groups were tested by using independent group comparisons. Results showed that in JHS/EDS-HT: (1) migraine has an earlier onset (12.6 vs 17 years of age; p = 0.005); (2) the rate of migraine days/month is higher (15 vs 9.3 days/month; p = 0.01); (3) accompanying symptoms are usually more frequent; (4) HIT-6 and MIDAS scores are higher (p = 0.04 and p = 0.03); (5) efficacy of rescue medication is almost identical, although, total drug consumption is significantly lower (p < 0.04). Joint hypermobility syndrome and Ehlers-Danlos syndrome, hypermobility type patients have a more severe headache syndrome with respect to the MO group, therefore demonstrating that migraine has a very high impact on quality of life in this disease.

Topiramate modulates habituation in migraine: evidences from nociceptive responses elicited by laser evoked potentials.

BACKGROUND: Lack of habituation during repetitive stimulation is the most consistent interictal abnormality of cortical information processing observed in migraine. Preventive migraine treatments might act by stabilizing cortical excitability level and thus the habituation to external stimuli. METHODS: We examined the effects of preventive treatment with topiramate on migraineur's habituation to nociceptive stimulation. Scalp potentials were evoked by Nd-YAP Laser stimulation of the hand dorsum and supraorbital region in 13 patients with migraine without aura (MO) and 15 healthy volunteers (HV). The exam was repeated in MO before and after treatment. RESULTS: We observed a lack of habituation and lower initial amplitudes in MO compared to HV. These abnormalities reached statistical significance for N1 LEPs component, generated in the secondary somatosensory cortex (SII), but not for N2/P2 complex, generated in the insula and anterior cingulated cortex (ACC). Topiramate normalized the N1 habituation pattern in MO, with a significant correlation between clinical effects and normalization of neurophysiological responses. CONCLUSIONS: Our results indicate a modulating action of topiramate on cortical processing of sensorial stimuli, mainly regarding the sensory-discriminative component of pain, elaborated by SII, without a significant effect on the affective dimension of pain, in which the ACC has an important role.

Cardioembolic stroke: Protective effect of a severe internal carotid artery stenosis in a patient with cardiac embolism.

Cardioembolic stroke is generally caused by intracranial artery occlusion. Clots may be identified in the intracranial vessels by means of conventional neuroimaging in the acute phase. High-resolution ultrasonography may show some features suggestive of cardiac emboli when occluding extracranial carotid arteries. We describe a patient with cardioembolic ischemic stroke in the right hemisphere in whom a left internal carotid artery stenosis paradoxically protected the ipsilateral hemisphere from distal intracranial embolism. The patient also presented multiple acute ischemic embolic lesions in the right middle cerebral artery territory and in the right occipital lobe, which was fed by the posterior cerebral artery, anomally originating from the right carotid siphon. Interestingly, the left internal carotid artery--which showed a severe preexisting stenosis--was occluded by the cardiac clot, whereas the right internal carotid artery only presented a moderate stenosis that had probably allowed the clots to pass. Therefore, the severe left internal carotid artery stenosis may have blocked the cardiac embolus, preventing it from reaching the ipsilateral hemisphere.

Effects of intermittent theta burst stimulation on cerebral blood flow and cerebral vasomotor reactivity.

OBJECTIVES: To determine whether intermittent theta burst stimulation influences cerebral hemodynamics, we investigated changes induced by intermittent theta burst stimulation on the middle cerebral artery cerebral blood flow velocity and vasomotor reactivity to carbon dioxide (CO(2)) in healthy participants. The middle cerebral artery flow velocity and vasomotor reactivity were monitored by continuous transcranial Doppler sonography. Changes in cortical excitability were tested by transcranial magnetic stimulation. METHODS: In 11 healthy participants, before and immediately after delivering intermittent theta burst stimulation, we tested cortical excitability measured by the resting motor threshold and motor evoked potential amplitude over the stimulated hemisphere and vasomotor reactivity to CO(2) bilaterally. The blood flow velocity was monitored in both middle cerebral arteries throughout the experimental session. In a separate session, we tested the effects of sham stimulation under the same experimental conditions. RESULTS: Whereas the resting motor threshold remained unchanged before and after stimulation, motor evoked potential amplitudes increased significantly (P = .04). During and after stimulation, middle cerebral artery blood flow velocities also remained bilaterally unchanged, whereas vasomotor reactivity to CO(2) increased bilaterally (P = .04). The sham stimulation left all variables unchanged. CONCLUSIONS: The expected intermittent theta burst stimulation-induced changes in cortical excitability were not accompanied by changes in cerebral blood flow velocities; however, the bilateral increased vasomotor reactivity suggests that intermittent theta burst stimulation influences the cerebral microcirculation, possibly involving subcortical structures. These findings provide useful information on hemodynamic phenomena accompanying intermittent theta burst stimulation, which should be considered in research aimed at developing this noninvasive, low-intensity stimulation technique for safe therapeutic applications.

An observational electro-clinical study of status epilepticus: from management to outcome.

Status epilepticus (SE) is a neurological emergency associated with a high morbidity and mortality. A prospective 3-year study was conducted in our hospital on 56 consecutive inpatients with SE. Demographic and clinical data were collected. EEG and clinical SE features were considered for the SE classification, both separately and together. The etiology of SE was determined. Patients were treated according to international standardized protocols of guidelines for the management of epilepsy. Response to treatment was evaluated clinically and electrophysiologically. Outcome at 30 days was considered as good, poor or death. Convulsive SE (CSE) was observed in 35 patients and non-convulsive SE (NCSE) in 21. Patients with CSE, in particular focal-CSE, were older than those with NCSE. As regards etiology, patients with SE secondary to cerebral lesions were the oldest, followed by patients with anoxic SE and those with toxic dysmetabolic SE. A first-line treatment was usually sufficient to control seizure activity in lesional and epileptic SE, while more aggressive treatment was necessary in all anoxic SE patients. Outcome was good in 35 patients, poor in 12, while 9 died. A prompt neurophysiological EEG evaluation, combined with the clinical evaluation, helps to make a rapid prognosis and take therapeutic management decisions. First-line treatments may be sufficient to control electro-clinical status in lesional and epileptic SE, while intensive care unit management, a more aggressive therapeutic approach and continuous EEG monitoring are recommended for refractory SE.

Cerebral vascular response in airmen exposed to hypobaric hypoxia.

INTRODUCTION: Cerebral vascular response via local and reflex adjustments is part of the integrated response to hypoxia and is coupled with changes in systemic vascular resistances that allow a redistribution of blood flow toward the brain. The cerebral vascular response in airmen exposed to simulated high altitude is not clear, thus we sought to investigate this aspect. METHODS: Four healthy military airmen were exposed to simulated high altitude in a hypobaric chamber according to a standard training protocol. Blood saturation (SpO2) and blood flow velocity with transcranial Doppler from the left middle cerebral artery (Vm) were continuously recorded. Pulsatility Index (PI), resistance index (RI), and systolic/diastolic ratio (S/D ratio) were computed. Alternate hypoxia-hyperoxia trials for 2 and 1 min, respectively, were used to assess the cerebrovascular response. RESULTS: Acute hypoxia induced an increase in Vm that promptly recovered when the oxygen supply was restored (mean increase of 5.5% at 18,000 ft and 17.2% at 25,000 ft). Alternate hypoxia-hyperoxia at 25,000 and 18,000 ft elicited changes in both SpO2 and Vm. In hypoxia, PI significantly decreased (mean decrease o" 25.6% at 18,000 ft and 39.5% at 25,000 ft), as did RI (mean decrease of 18.7% at 18,000 ft and 34.4% at 25,000 ft), while S/D ratio increased. DISCUSSION: The standard altitude training protocol induced a transient cerebrovascular response. The response was as expected, with hypoxia-induced vasodilation and opposite changes when breathing pure oxygen.