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Badel T, Bašić Kes V, Jerolimov V, Zadravec D, Savić-Pavičin I, Anić Milošević S. EVAULATION OF BLINK REFLEX BETWEEN PATIENTS WITH IDIOPATHIC TRIGEMINAL NEURALGIA AND HEALTHY VOLUNTEERS. Acta Clin Croat 2022; 61:121-128. [PMID: 36824643 PMCID: PMC9942457 DOI: 10.20471/acc.2022.61.s2.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
The purpose of the study was to find differences in the parameters of the response to the blink reflex (BR) between patients with idiopathic trigeminal neuralgia (TN) and health volunteers. A prospective cohort study was conducted over 2 years. The TN-subgroup included 15 patients (mean age / SD 62.3 ± 10.7 years). Pain-free and healthy volunteers as a HV-subgroup (mean age / SD: 30.8 ± 8.1 years) were recruited from asymptomatic students of dental medicine. Diagnostic parameters were determined by measuring latency to the onset of the BR components from electric stimulation. The following branches of the trigeminal nerve were affected: maxillary branch only (26.7%), mandibular branch only (20%), combined: ophthalmic branch with maxillary branch (6.7%), and ophthalmic branch with mandibular branch (6.7%) respectively, combined maxillary and mandibular branch (26.7%) and affected all three branches (13.4%). The latencies of the BR, left and right side together, between subgroups were significantly higher for values R1 (homolateral early response), R2 (homolateral late response), R2c latency (contralaterally expressed response) in the TN-subgroup (p < 0.05). On the basis of the presence of R1c and R3 latencies and upon considering the abnormal findings of the BR, no statistically significant differences were found between the examined subgroups (p > 0.05). Blink-reflex parameters (R1, R2 and R2c) were significantly abnormal comparing TN-patients with healthy volunteers. The R3 component of the BR was related to noxious stimuli, likewise by innocuous stimuli.
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Affiliation(s)
- Tomislav Badel
- Department of Removable Prosthodontics, School of Dental Medicine, University of Zagreb, Zagreb, Croatia
| | - Vanja Bašić Kes
- Department of Neurology, Clinical Hospital Centre “Sisters of Charity”, University of Zagreb, Zagreb, Croatia
| | | | - Dijana Zadravec
- Department of Diagnostic and Interventional Radiology, Clinical Hospital Centre “Sisters of Charity”, University of Zagreb, Zagreb, Croatia
| | - Ivana Savić-Pavičin
- Department of Dental Athropology, School of Dental Medicine, University of Zagreb, Zagreb, Croatia
| | - Sandra Anić Milošević
- Department of Orthodontics, School of Dental Medicine, University of Zagreb, Zagreb, Croatia
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Ma C, Tian F, Zhou L, Gu J, Zhang X, Quan J, Qu J, Yan X. Blink reflex: A practical test to evaluate the trigeminal nerve injury following percutaneous balloon compression for the treatment of trigeminal neuralgia. Headache 2022; 62:363-373. [PMID: 35181896 DOI: 10.1111/head.14269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/13/2022] [Accepted: 01/14/2022] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To evaluate the blink reflex (BR) in estimating the potential injury of trigeminal nerve following percutaneous balloon compression (PBC) surgery, and to determine the association between BR alterations and early surgical outcomes. METHODS In this single-center, prospective before-and-after study, a total of 74 patients who had primary trigeminal neuralgia and scheduled for PBC between October 2020 and June 2021 were prospectively included. BR testing and facial sensory assessment were performed pre- and post-PBC. The latency and the area under the curve (AUC) of pre- and postoperative R1 (R1pre /R1post ) and R2 (R2pre /R2post ) were measured. RESULTS The BR components were noticeably delayed or diminished following PBC. R1post was elicited in only 26 patients, and absent in 48 patients. The residual R1post had markedly reduced AUC (median difference [Hodges-Lehmann]: -59.5, 95% confidence interval [CI]: -217.5 to -6.9, p = 0.023). Compared with R2pre , the latency of R2post was considerably delayed (mean difference: 4.3, 95% CI: 2.9 to 5.7, p < 0.001) and the AUC was greatly suppressed (median difference [Hodges-Lehmann]: -388.4, 95% CI: -548.4 to -259.5, p < 0.001). After PBC, 58 patients had immediate total pain relief, and 16 had partial relief. The absence of R1post was found in 46 of 58 (79.3%) patients with complete remission, whereas in only 2 of 16 (12.5%) patients with partial relief. Association analysis showed that the absence of R1post was strongly associated with total pain relief (46/58 [79.3%] vs. 2/16 [12.5%], odds ratio [OR]: 26.8, 95% CI: 5.4 to 134.5, Cramér's V: 0.6, p < 0.001). The latency of R2post in patients with total relief was significantly delayed (mean difference: 2.5, 95% CI: 0.3 to 4.6, p = 0.028). Patients experienced graded facial numbness after PBC, of whom 31 reported mild numbness (Grades I-II) and 43 reported more severe numbness (Grades III-IV). The absence of R1post was significantly associated with facial numbness severity, 33/43 (76.7%) in Grades III-IV vs. 15/31 (48.4%) in Grades I-II (OR: 0.284, 95% CI: 0.105 to 0.771, Cramér's V: 0.3, p = 0.012). In patients with more severe numbness, the latency of R2post was significantly delayed (mean difference: 2.7, 95% CI: 0.1 to 5.3, p = 0.043), and the reduction of AUC was much greater (median difference [Hodges-Lehmann]: 17.2, 95% CI: 0.5 to 35.4, p = 0.041). CONCLUSION Both R1 and R2 were significantly diminished after PBC and these alterations were associated with early surgical outcomes, suggesting that the BR is useful in evaluating trigeminal injury following PBC and could provide objective information about early prognosis.
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Affiliation(s)
- Chengwen Ma
- Department of Neurosurgery, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Fuyu Tian
- Department of Neurosurgery, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Le Zhou
- Department of Neurosurgery, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Junxiang Gu
- Department of Neurosurgery, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Xi Zhang
- Department of Neurosurgery, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Junjie Quan
- Department of Neurosurgery, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Jianqiang Qu
- Department of Neurosurgery, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Xianxia Yan
- Department of Neurosurgery, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
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Zhang R, Zhang X, Chen Y, Song W. Current perception threshold testing in chronic ankle instability. BMC Musculoskelet Disord 2021; 22:453. [PMID: 34006258 PMCID: PMC8132381 DOI: 10.1186/s12891-021-04345-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 05/10/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Damage to sensory input is an underlying pathology of chronic ankle instability (CAI). Therefore, it is necessary to evaluate the sensory function of patients with CAI. The present study quantitatively evaluated sensory nerve function in patients with CAI and healthy controls using current perception threshold (CPT) measurements, as well as the influence of sex, age, and body mass index (BMI) on CPT values and the relations between CPT frequencies. METHODS Fifty-nine subjects with CAI and 30 healthy controls participated in this study. CPT values at the anterior talofibular ligament region were recorded on the injured and uninjured sides in CAI patients and on both sides in the healthy control group. Between group differences were compared. The influence of sex, age and BMI on CPT values was evaluated. Correlations between different frequencies were also studied. RESULTS There were no significant differences in age, sex, height, weight or BMI between the CAI and healthy control groups. The CPT values did not show a significant difference by sex. The CPT values did not significantly correlate with age or BMI. Compared to the control group, the CAI group had significantly higher CPT values on the injured and uninjured sides under 250-Hz and 5-Hz electrical stimuli; the difference between the groups was significant (p < 0.01), and the effect size were large. No significant difference was observed under 2000-Hz stimuli. There were correlations between CPT values at different frequencies (p < 0.01), especially 250 Hz and 5 Hz. CONCLUSION The present study revealed increased sensory thresholds in 250-Hz- and 5-Hz-related sensory nerve fibres in the injured and uninjured ankles of patients with CAI. This increase may indicate dysfunction of A-delta and C fibres. Sex, age and BMI did not significantly impact CPT values. There were correlations between CPT values at different frequencies, especially 250 Hz and 5 Hz. LEVEL OF EVIDENCE Level III, case-control study.
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Affiliation(s)
- Ran Zhang
- Department of Rehabilitation, Xuanwu Hospital, Capital Medical University, 45 Changchunjie, Beijing, 100054 China
- Department of Rehabilitation, Beijing Tongren Hospital, Capital Medical University, 1 Dongjiaominxiang, Beijing, 100730 China
| | - Xi Zhang
- Department of Rehabilitation, Beijing Tongren Hospital, Capital Medical University, 1 Dongjiaominxiang, Beijing, 100730 China
| | - Yaping Chen
- Department of Rehabilitation, Beijing Tongren Hospital, Capital Medical University, 1 Dongjiaominxiang, Beijing, 100730 China
| | - Weiqun Song
- Department of Rehabilitation, Xuanwu Hospital, Capital Medical University, 45 Changchunjie, Beijing, 100054 China
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Bendtsen L, Zakrzewska JM, Abbott J, Braschinsky M, Di Stefano G, Donnet A, Eide PK, Leal PRL, Maarbjerg S, May A, Nurmikko T, Obermann M, Jensen TS, Cruccu G. European Academy of Neurology guideline on trigeminal neuralgia. Eur J Neurol 2019; 26:831-849. [DOI: 10.1111/ene.13950] [Citation(s) in RCA: 191] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 03/08/2019] [Indexed: 12/19/2022]
Affiliation(s)
- L. Bendtsen
- Department of Neurology Faculty of Health and Medical Sciences Danish Headache Center Rigshospitalet‐Glostrup University of Copenhagen Glostrup Denmark
| | - J. M. Zakrzewska
- Pain Management Centre National Hospital for Neurology and Neurosurgery London UK
- Eastman Dental Hospital UCLH NHS Foundation Trust London UK
| | - J. Abbott
- Trigeminal Neuralgia Association UK Oxted Surrey UK
| | | | - G. Di Stefano
- Department of Human Neuroscience Sapienza University Rome Italy
| | - A. Donnet
- Headache and Pain Department CHU La Timone APHM Marseille France
| | - P. K. Eide
- Department of Neurosurgery Oslo University Hospital‐Rikshospitalet Oslo Norway
- Institute of Clinical Medicine Faculty of Medicine University of Oslo Oslo Norway
| | - P. R. L. Leal
- Department of Neurosurgery Faculty of Medicine of Sobral Federal University of Ceará Sobral Brazil
- University of Lyon 1 Lyon France
| | - S. Maarbjerg
- Department of Neurology Faculty of Health and Medical Sciences Danish Headache Center Rigshospitalet‐Glostrup University of Copenhagen Glostrup Denmark
| | - A. May
- Department of Systems Neuroscience Universitäts‐Krankenhaus Eppendorf Hamburg Germany
| | - T. Nurmikko
- Neuroscience Research Centre Walton Centre NHS Foundation Trust Liverpool UK
| | - M. Obermann
- Center for Neurology Asklepios Hospitals Schildautal Seesen Germany
| | - T. S. Jensen
- Department of Neurology and Danish Pain Research Center Aarhus University Hospital University of Aarhus Aarhus C Denmark
| | - G. Cruccu
- Department of Human Neuroscience Sapienza University Rome Italy
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Gündüz A, Uygunoğlu U, Uluduz D, Saip S, Siva A, Göksan B, Kızıltan ME. Reduced inhibition in brainstem circuits in classical trigeminal neuralgia. Eur J Pain 2018; 23:142-149. [PMID: 30055103 DOI: 10.1002/ejp.1293] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/09/2018] [Indexed: 12/19/2022]
Abstract
OBJECTIVE We hypothesized that prepulse modulation (PPM) would be altered in trigeminal neuralgia (TN) if suprasegmental inhibitory network involvement was present and tested our hypothesis in a group of patients with classical TN. METHODS The study enrolled nine consecutive patients with classical TN and 14 healthy subjects. Diagnosis and classification followed the International Classification of Headache Disorders-third edition (beta version). The blink reflex (BR) and BR-PPM were recorded. Ipsilateral recordings were made after stimulating each trigeminal nerve in the patient group whereas right-sided recordings were performed after stimulating the right trigeminal nerve in the healthy subjects. A conditioning electrical stimulus was applied to the ipsilateral median nerve at interstimulus intervals (ISIs) of 50 and 100 ms before the test stimulus to the supraorbital nerve. RESULTS The unconditioned BR recordings were similar in all groups. In the healthy subjects, the prepulse stimulus resulted in a reduced R2 magnitude (p = 0.000, Friedman's test) and longer R2 latency (p = 0.008, Friedman's test) at ISIs of 50 and 100 ms in comparison with unconditioned recordings. The R2 latency differed significantly between the unconditioned recordings and the ISI of 100 ms. In the patients with TN, no significant change was observed on either the symptomatic or asymptomatic sides. CONCLUSIONS There is a bilateral prepulse inhibition deficit in TN, even on the asymptomatic side. Our findings provide electrophysiological evidence for suprasegmental changes and loss of filtering activity at the brainstem in level TN.
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Affiliation(s)
- A Gündüz
- Department of Neurology, Cerrahpasa Medical School, Istanbul University, Turkey
| | - U Uygunoğlu
- Department of Neurology, Cerrahpasa Medical School, Istanbul University, Turkey
| | - D Uluduz
- Department of Neurology, Cerrahpasa Medical School, Istanbul University, Turkey
| | - S Saip
- Department of Neurology, Cerrahpasa Medical School, Istanbul University, Turkey
| | - A Siva
- Department of Neurology, Cerrahpasa Medical School, Istanbul University, Turkey
| | - B Göksan
- Department of Neurology, Cerrahpasa Medical School, Istanbul University, Turkey
| | - M E Kızıltan
- Department of Neurology, Cerrahpasa Medical School, Istanbul University, Turkey
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Chen MJ, Yang C, Huang D, He DM, Wang YW, Zhang WH. Modified technique for preservation of inferior alveolar nerve during mandibulectomy. Head Neck 2017; 39:2562-2566. [PMID: 28963787 DOI: 10.1002/hed.24924] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/26/2017] [Accepted: 07/17/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The purpose of this article is to introduce the modified technique of preservation of the inferior alveolar nerve (IAN) during mandibulectomy for a benign lesion. METHODS Five cases of osteofibrous hyperplasia and 3 cases of centricity osteomyelitis were included. During surgery, the IAN was marked using a planned cutting guide. Using an oscillating saw, the depth of the osteotomy along the IAN was controlled until the bone cortex was cut through. After splitting, the bony section was removed, leaving the neurovascular bundle intact. The sensation of the lower lip was evaluated using current perceptive threshold testing during follow-up. RESULTS After follow-up for 6-27 months, no recurrence or secondary deformity was found. One patient had severe sensory disturbance. CONCLUSION With the use of a cutting guide and osteotomy tricks, mandibulectomy with preservation of the IAN can be accurately performed.
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Affiliation(s)
- Min-Jie Chen
- Department of Oral Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People's Republic of China
| | - Chi Yang
- Department of Oral Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People's Republic of China
| | - Dong Huang
- Department of Oral Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People's Republic of China
| | - Dong-Mei He
- Department of Oral Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People's Republic of China
| | - Yi-Wen Wang
- Department of Oral Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People's Republic of China
| | - Wen-Hao Zhang
- Department of Oral Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, People's Republic of China
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Chen Y, Mao CJ, Li SJ, Wang F, Chen J, Zhang HJ, Li L, Guo SS, Yang YP, Liu CF. Quantitative and fiber-selective evaluation of pain and sensory dysfunction in patients with Parkinson's disease. Parkinsonism Relat Disord 2015; 21:361-5. [DOI: 10.1016/j.parkreldis.2015.01.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 12/20/2014] [Accepted: 01/11/2015] [Indexed: 11/27/2022]
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The current perception threshold test differentiates categories of mechanical neck disorder. J Orthop Sports Phys Ther 2014; 44:532-40, C1. [PMID: 24981222 DOI: 10.2519/jospt.2014.4691] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
STUDY DESIGN Cross-sectional discriminative analysis. OBJECTIVE To determine whether current perception threshold (CPT) can differentiate between categories of patients with mechanical neck disorders (MNDs). BACKGROUND Neck pain is the third most common musculoskeletal disorder and affects a third of all adults each year. It can present as neck pain without musculoskeletal signs, neck pain with musculoskeletal signs but no neurological signs, or neck pain with neurological signs. CPT testing can assess altered sensory perception that may reflect neurological changes. METHODS Patients with MNDs (n = 106) were classified into 3 groups, based on a standardized musculoskeletal examination process performed by an experienced physiotherapist who was blinded to CPT scores. The 3 groups were defined as neck pain without musculoskeletal signs (MND I) (n = 60), neck pain with musculoskeletal signs (MND II) (n = 29), and neck pain with neurological signs (MND III) (n = 17). A rapid protocol of CPT testing was performed at 3 frequencies (5, 250, and 2000 Hz), using 3 dermatomal locations on the hand. A 1-way analysis of variance with post hoc comparison and effect sizes was calculated to compare the mean CPT scores between the groups. A binary logistic-regression model was used to predict probability of higher CPT in MND III and to create a receiver-operating-characteristic curve. RESULTS Mean CPT differed significantly across the 3 MND groups (MND I, 9.7; MND II, 10.6; and MND III, 11.8; P<.001; η(2) = 0.6). Post hoc comparisons indicated differences between MND I and MND II (P = .05) and between MND II and MND III (P = .01) that had large effect sizes (MND I versus II, d = 1 and MND II versus III, d = 2.2). CPT testing was able to distinguish between MND II and III when a threshold value of greater than 11 was used to indicate MND III. The predicted probability of abnormal CPT in MND III had an estimated 73% sensitivity and 81% specificity; the odds ratio was 11.5 (P = .001) for the differentiation capacity of CPT between MND II and III, with a cutoff of 11. The area under the receiver-operating-characteristic curve was 0.84 (95% confidence interval: 0.72, 0.96; P<.001). CONCLUSION CPT testing has moderate discriminatory accuracy, specificity, and sensitivity for classification of MND categories into neck pain with or without neurological signs. J Orthop Sports Phys Ther 2014;44(7):532-540. Epub 10 May 2014. doi:10.2519/jospt.2014.4691.
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Liang L, Diao Y, Xu Q, Zhang M. Transcranial segment of the trigeminal nerve: macro-/microscopic anatomical study using sheet plastination. Acta Neurochir (Wien) 2014; 156:605-12. [PMID: 24158246 DOI: 10.1007/s00701-013-1920-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Accepted: 10/09/2013] [Indexed: 01/07/2023]
Abstract
BACKGROUND Trigeminal neuralgia (TN) may be caused by the mechanical compression of the trigeminal nerve. In the studies on the location of mechanical irritation and entrapment of the nerve, attention has been paid mostly to vascular structures in the subarachnoid space. Few studies have explored the relationship between the trigeminal nerve and its surrounding structures along its course in the skull base. The aim of this study was to examine and trace the root, ganglion and three divisions of the trigeminal nerve and their relationships with surrounding soft and bony structures in the skull base, and to identify the likely mechanical compression points. METHODS A total of 26 adult cadavers (ten females, 16 males; age range, 45-81 years) were examined in this study, eight for dissection and 16 for sheet plastination study. RESULTS Anatomical structures that may make the trigeminal nerve susceptible to entrapment in the skull base were located at (1) the inferolateral edge of the mouth of Meckel's cave, (2) the middle cranial fossa dura and the lateral wall of the anterior intracavernous portion of the internal carotid artery, (3) the ridge of the medial wall of the foramen rotundum, and (4) the twisted periosteum and venous plexus of the foramen ovale. CONCLUSION This study identified four likely mechanical compression points along the course of the trigeminal nerve in the skull base. Knowledge of these TN-susceptible sites may be useful to both skull base surgeon and TN-animal model researcher, particularly when they study TN without vascular compression.
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Affiliation(s)
- Liang Liang
- Department of Anatomy, Capital Medical University, Beijing, China
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Mayhew J. Application of trigeminal-evoked responses to headshaking in horses. Vet J 2012; 191:15-6. [DOI: 10.1016/j.tvjl.2011.04.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 04/30/2011] [Indexed: 11/15/2022]
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Diagnostic value of some less frequently considered blink reflex parameters in idiopathic trigeminal neuralgia. Wien Klin Wochenschr 2011; 123:646-9. [DOI: 10.1007/s00508-011-0074-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Accepted: 08/11/2011] [Indexed: 10/15/2022]
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Nociceptive trigeminal reflexes in non-sedated horses. Vet J 2011; 191:101-7. [PMID: 21664846 DOI: 10.1016/j.tvjl.2011.03.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 03/17/2011] [Accepted: 03/26/2011] [Indexed: 11/24/2022]
Abstract
Electrically induced reflexes can be used to investigate the physiology and pathophysiology of the trigeminal system in humans. Similarly, the assessment of the trigemino-cervical (TCR) and blink reflexes (BR) may provide a new diagnostic tool in horses. The aim of this study was to evoke nociceptive trigeminal reflexes and describe the electrophysiological characteristics in non-sedated horses. The infraorbital (ION) and supraorbital nerves (SON) were stimulated transcutaneously in 10 adult Warmblood horses in separate sessions using train-of-five electrical pulses. The current was increased gradually until the TCR threshold was found. The stimulus-response curve of the TCR was evaluated. At the same time as TCR, the BR response was also assessed. Surface electromyographic (EMG) responses were recorded from the orbicularis oculi, splenius and cleidomastoideus muscles. Latency, duration, amplitude of the reflexes and behavioural responses were analysed. Noxious electrical stimulation of the ION or SON evoked reflex EMG responses, with similar features regardless of the nerve that had been stimulated. Stimulations of increasing intensity elicited reflexes of increasing amplitude and decreasing latency, accompanied by stronger behavioural reactions, therefore confirming the nociceptive nature of the TCR. These findings provide a reference for the assessment of dysfunction of the equine trigeminal system.
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