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Josep Valls-solé - One of the best experts on this subject based on the ideXlab platform.
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O-13 Control over Supraorbital Nerve stimulation overrules the facilitation of blink reflex in defensive peripersonal space
Clinical Neurophysiology, 2019Co-Authors: Viviana Versace, Josep Valls-solé, Stefania Campostrini, Luca Sebastianelli, Leopold Saltuari, Markus KoflerAbstract:Background The blink reflex (BR) to electrical Supraorbital Nerve stimulation (SON-S) is a protective reflex. Knowledge about imminent SON-S via acoustic prepulse, verbal forewarning, or self-delivery of stimulation, causes R2 suppression. The BR following median Nerve stimulation increases when elicited in the defensive peripersonal space of the face (DPPS-F). Here we studied modulation of BR to SON-S by self-stimulation or visual control over hetero-stimulation in or outside the DPPS-F. Methods Twenty-three subjects participated in two sets of BR recordings following SON-S (E1, n = 10; E2, n = 17). Conditions either involved hetero-stimulation by the experimenter (E1A, E1C, E2A, E2B) or self-stimulation by subjects (E1B, E2C, E2D), with the stimulator probe in (E1B, E1C, E2B, E2D) or outside (E1A, E2A, E2C) their DPPS-F, and with subjects being aware (E1B, E2B, E2C, E2D) or unaware (E1A, E1C, E2A) about imminent stimulation. Results Compared to baseline (standard BR, E1A, E2A), R2 was facilitated with the probe held in the DPPS-F, but being unaware of stimulus triggering (E1C). Visual control of imminent stimulation (seeing the experimenter’s finger triggering the probe: E2B) and self-triggering (E1B, E2C, E2D) facilitated R1 and inhibited R2. With self-triggering, there was no difference between the probe in (E2C) or outside (E2D) the DPPS-F. Conclusion BR-R2 is facilitated in a threatening situation (probe in DPPS-F) without control (hetero-stimulation unseen by subject). R1 is facilitated and R2 inhibited when subjects have visual control or full initiative over stimulation, irrespective of seeing the probe in the DPPS-F or not.
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BS20. Prepulse inhibition of the blink reflex by thermoalgesic stimuli in healthy humans
Clinical Neurophysiology, 2018Co-Authors: Lilia Isabel Correa Márquez, Karem Cardenas, Jordi Casanova-molla, Josep Valls-soléAbstract:Introduction All sensory stimuli produce transient excitability changes in various central nervous system circuits. One example is prepulse inhibition (PPI), which is the inhibition generated by a weak conditioning stimulus (prepulse) over the reflex response to a subsequent suprathreshold stimulus. The PPI is a ubiquitous phenomenon, common to many different sensory modalities, it has been described with auditory, electrical and laser stimuli. We considered that thermoalgesic stimuli would also cause PPI, even though these stimuli take relatively long time to reach their peak. Our aim was twofold: 1. Determine when PPI is generated along the stimulus build-up and 2. Determine if conscious awareness (AW) of the stimulus is modified by PPI. Methods In 18 healthy volunteers, we applied electrical stimuli to the Supraorbital Nerve to elicit the blink reflex. In test trials, subjects had also a thermoalgesic stimulus applied to the skin of the forearm at variable time intervals preceding the Supraorbital Nerve stimulus. Subjects were requested to tell the minute mark shown by the handle of a Libet’s clock positioned at 1 m distance from the subject’s eyes at the time they felt the stimulus. AW was calculated as the difference between the time defined by the handle position and the real time at which the stimulus was issued. We determined the effects of thermoalgesic stimuli on the blink reflex by measuring the size of R1 and R2 responses in test trials as percentages of the mean in control trials, and the onset of the PPI effect as the time interval in which the R2 response of the blink reflex became less than 40% of the mean baseline. We, then, determined the temporal relationship between PPI and AW of both, the thermoalgesic stimulus, to know if PPI occurred before or after the thermoalgesic stimulus was made conscious, and the Supraorbital Nerve stimulus, to know if PPI had any effect on conscious AW of the test stimulus. Results Thermoalgesic stimuli induced facilitation of R1 at a mean of 332 ms (±37 ms) and R2 inhibition at 392 ms (±49 ms). Mean latency of AW was 761 ms (±33 ms) for thermoalgesic stimuli and 370 ms (±20 ms) for Supraorbital Nerve stimuli. Both were modified at the time when AW of the two stimuli coincided: AW of the Supraorbital Nerve stimulus was advanced (15.6% ± 14.1% with respect to baseline at the interval of 500 ms) and AW of the thermoalgesic stimulus was delayed (14.5% ± 15.8% with respect to baseline at the interval of 700 ms). Conclusion Prepulse inhibition is accompanied by a change in conscious perception. The effect is limited to the time when conscious appraisal of the two stimuli coincide in the central nervous system, when subjects tend to consider prepulse and pulse stimuli closer to each other than they really are. Subcortical gating of sensory inputs may modulate not only brainstem responses, but also conscious perception time.
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An excitatory reflex between R1 and R2 responses of the blink reflex to Supraorbital Nerve stimuli
Clinical Neurophysiology, 2016Co-Authors: L. Leon, C. Cabib, M. Cordoso, I. Motta, Josep Valls-soléAbstract:Background The typical pattern of the blink reflex to ipsilateral electrical stimuli to the Supraorbital Nerve (SN) is composed by an early, short duration, well synchronized, R1 response and a late, long duration, polyphasic R2 response. We examined whether the period between R1 and R2 results from lack of excitatory inputs or active inhibition. Methods Tests were performed in 5 healthy subjects and 10 patients of various disorders affecting blink reflex excitability, including postparalytic facial syndrome and hemifacial spasm. All subjects wore surface electrodes attached to the orbicularis oculi and stimuli were applied to the SN. After obtaining the conventional blink reflex, healthy subjects were requested to close their eyes at various levels of force while applying again the same stimulus. Results In healthy subjects closing the eyes with force, SN stimulation induced a response of smaller amplitude and shorter latency than the R2 (25.2 ± 1.3 ms). A short and incomplete silent period emerged after R1 and after R2. Patients with postparalytic facial syndrome and essential hemifacial spasm showed activity interfering with the silence between R1 and R2, with often expanding between the two responses, repeating in successive trials. Conclusions Our results show that there can be reflex responses between R1 and R2 in healthy subjects during contraction and in patients with abnormal reflex excitability. This suggests that the absence of activity between the two responses in normal conditions is the consequence of an active inhibition that reaches the facial motoneurons at that point.
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Blink reflex in patients with Wallenberg’s syndrome
Journal of neurology, 1997Co-Authors: Nicolás Vila, Josep Valls-solé, Victor Obach, Albert Saiz, M. Alday, Ángel ChamorroAbstract:Knowledge of the neural circuits involved in Wallenberg’s syndrome (WS) is incomplete. Study of the blink reflex (BR) in patients with WS can help in reaching a better understanding of the physiopathology underlying clinical symptoms and may help in the prediction of clinical outcome. We evaluated the BR in response to Supraorbital Nerve electrical stimuli in 20 patients with WS. All patients were studied within the 1st week after onset of symptoms, and 10 of them were also studied repeatedly during a follow-up period of 3–12 months. At the first examination the long latency bilateral responses (R2 and R2c) to stimulation of the Supraorbital Nerve of the affected side were absent in 11, delayed in 4, and normal in 5 patients. At follow-up, there was a normalization of the BR in all patients who had absent or delayed responses at the first examination except for one patient whose responses remained absent at the 9th month. Late responses elicited on the side of the lesion by stimulation of the non-affected Supraorbital Nerve were normal in all but one patient. This patient died from cardiorespiratory arrest within the 1st month of the illness. One patient with normal BR responses also died in the acute phase. The BR is abnormal in most patients with acute WS and tends to normalize in a mean period of 7 months. BR pattern is not a predictor of early fatal complications in patients with this syndrome.
Evaggelia Kararizou - One of the best experts on this subject based on the ideXlab platform.
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Clinical experience with transcutaneous Supraorbital Nerve stimulation in patients with refractory migraine or with migraine and intolerance to topiramate: a prospective exploratory clinical study.
BMC neurology, 2017Co-Authors: Michail Vikelis, Emmanouil V. Dermitzakis, Konstantinos C. Spingos, Georgios G. Vasiliadis, George S. Vlachos, Evaggelia KararizouAbstract:Abstract Background Migraine is included in the top-ten disabling diseases and conditions among the Western populations. Non-invasive neurostimulation, including the Cefaly® device, for the treatment of various types of pain is a relatively new field of interest. The aim of the present study was to explore the clinical experience with Cefaly® in a cohort of migraine patients previously refractory or intolerant to topiramate prophylaxis. Methods A prospective, multi-center clinical study was performed in patients diagnosed with episodic or chronic migraine with a previous failure to topiramate treatment requiring prevention with Cefaly® according to the treating physician’s suggestion. A 1-month period of baseline observation was followed by a 3-month period of observation during the use of transcutaneous Supraorbital Nerve stimulation (t-SNS) with Cefaly® as the only preventive treatment. Results A small but statistically significant decline was shown over time in the number of days with headache (HA), the number of days with HA with intensity ≥5/10, and the number of days with use of acute medication after 3 months ( p Conclusion Three-months of preventive treatment for episodic or chronic migraine with t-SNS proved to be an effective, safe and well tolerated option for the treatment of patients with migraine who were intolerant or did not respond to topiramate. Trial registration ClinicalTrials NCT03125525 . Registered 21 April 2017.
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Clinical experience with transcutaneous Supraorbital Nerve stimulation in patients with refractory migraine or with migraine and intolerance to topiramate: a prospective exploratory clinical study
BMC, 2017Co-Authors: Michail Vikelis, Emmanouil V. Dermitzakis, Konstantinos C. Spingos, Georgios G. Vasiliadis, George S. Vlachos, Evaggelia KararizouAbstract:Abstract Background Migraine is included in the top-ten disabling diseases and conditions among the Western populations. Non-invasive neurostimulation, including the Cefaly® device, for the treatment of various types of pain is a relatively new field of interest. The aim of the present study was to explore the clinical experience with Cefaly® in a cohort of migraine patients previously refractory or intolerant to topiramate prophylaxis. Methods A prospective, multi-center clinical study was performed in patients diagnosed with episodic or chronic migraine with a previous failure to topiramate treatment requiring prevention with Cefaly® according to the treating physician’s suggestion. A 1-month period of baseline observation was followed by a 3-month period of observation during the use of transcutaneous Supraorbital Nerve stimulation (t-SNS) with Cefaly® as the only preventive treatment. Results A small but statistically significant decline was shown over time in the number of days with headache (HA), the number of days with HA with intensity ≥5/10, and the number of days with use of acute medication after 3 months (p
S Anagnostopoulou - One of the best experts on this subject based on the ideXlab platform.
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Deep brain stimulation's anatomy: step by step evaluation of the extracerebral surgical technique
OA Anatomy, 2013Co-Authors: In Mavridis, A Michalinos, S AnagnostopoulouAbstract:Introduction Our purpose was to study the surgical anatomy of the deep brain stimulation technique, focusing on the extracerebral part of this minimally invasive procedure. Materials and methods Our study was based on four formalinembalmed adult human cadavers from cadaver donors. We created a set of deep brain stimulation-like materials for the extracerebral technique and formed a step by step diagram of the extracerebral surgical procedure. We also studied the course of the Supraorbital Nerve. Results A small intermediate incision at the midpoint of each tunnel significantly helps in decreasing the procedure’s duration and risks. The lateral limit of the subclavicular pocket’s incision must be vertical to the cervical tunnel axis in order to avoid accidental traumatism during tunneling. Information regarding the Supraorbital Nerve and skin landmarks of the head, for safer pins or fiducials’ placement, is also provided. Conclusion The extracerebral surgical technique hides uncommon anatomical details and difficult technical points. Their knowledge can help neurosurgeons in decreasing the observed complication rates.
Rohit Chhirolya - One of the best experts on this subject based on the ideXlab platform.
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Pearls & Oy-sters: Supraorbital neuralgia in lepromatus leprosy masquerading as SUNA
Neurology, 2019Co-Authors: Vimal Kumar Paliwal, Sucharita Anand, Anmol Singh Rai, Rohit ChhirolyaAbstract:Triad of continuous Supraorbital and forehead pain in the sensory territory of Supraorbital Nerve, a tender Supraorbital Nerve, and complete but transient improvement in pain after Supraorbital Nerve block characterize Supraorbital neuralgia.
Wendy A. Franks - One of the best experts on this subject based on the ideXlab platform.
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Supraorbital Nerve block in trabeculectomy surgery: an observational case series.
Clinical & experimental ophthalmology, 2006Co-Authors: Eugene Tay, Mohit Gupta, Wendy A. FranksAbstract:Thirteen patients completed a visual analogue pain scale after trabeculectomy with topical anaesthesia and a Supraorbital Nerve block with 2 mL of lignocaine 2%. Ease of surgery was graded on a scale of 0-5. Inadvertent eye movements and episodes of orbicularis spasm were recorded. Statistical analysis was performed using STATA software. Median pain score (range) during delivery of anaesthesia was 2 (1-5), during surgery was 0 (0-4) and postoperatively was 0 (0-3). Pain scores after surgery were significantly lower than during delivery of anaesthesia (Wilcoxon signed rank test, P = 0.0289). Three subjects had inadvertent eye movements with ease of surgery recorded as 1 of 5 in 12 cases and 2 of 5 in one case. The novel application of this anaesthetic technique offers adequate analgesia in trabeculectomy surgery. However, a larger scale comparative trial is needed to further evaluate the value of this technique.
