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Yin NH, Giulio ID, Hodkinson PD, Formenti F, Pollock RD. Sex differences in cervical disc height and neck muscle activation during manipulation of external load from helmets. Exp Physiol 2024. [PMID: 39120591 DOI: 10.1113/ep091996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 07/16/2024] [Indexed: 08/10/2024]
Abstract
Neck pain associated with helmet-wear is an occupational health problem often observed in helicopter pilots and aircrew. Whether aircrew helmet wearing is associated with physiological and biomechanical differences between sexes is currently unknown. This study investigated neuromuscular activation patterns during different helmet-wearing conditions. The helmet load was manipulated through a novel Helmet Balancing System (HBS) in healthy, non-pilot male and female participants (n = 10 each, age 19-45 years) in two phases. Phase A assessed the acute effects of helmet-wear on neck muscles activation during head movements. Phase B examined changes in muscle activity and cervical disc height after wearing a helmet for 45 min. In Phase A, muscle activity was similar between sexes in many movements, but it was higher in female participants when wearing a helmet than in males. The HBS reduced muscle activity in both sexes. In Phase B, female participants exhibited a greater level of muscular fatigue, and male participants' cervical disc height was significantly decreased [5.7 (1.4) vs. 4.4 (1.5) mm, P < 0.001] after continuous wearing. Both sexes showed no significant change in muscle fatigue and disc height [male: 5.0 (1.3) vs. 5.2 (1.4) mm, P = 0.604] after applying HBS. These findings demonstrate sex-specific physiological and biomechanical responses to wearing a helmet. They may indicate different postural and motor control strategies, associated with different neck pain aetiologies in male and female aircrew, the knowledge of which is important to reduce or prevent musculoskeletal injuries associated with helmet wearing. HIGHLIGHTS: What is the central question of this study? Do sex differences exist in the neck physiological response to helmet-wearing? What is the main finding and its importance? Sex differences exist in both the acute response and after 45 min of helmet wearing: during a given head movement, female participants' muscle activity was greater than male participants' and females also demonstrated greater muscular fatigue after continuous helmet-wear than males while cervical disc height showed a significant reduction after 45 min helmet-wear in males only. These findings could provide insight into future training or injury prevention strategy for pilots.
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Affiliation(s)
- Nai-Hao Yin
- Centre for Human and Applied Physiological Sciences, King's College London, London, UK
| | - Irene Di Giulio
- Centre for Human and Applied Physiological Sciences, King's College London, London, UK
| | - Peter D Hodkinson
- Centre for Human and Applied Physiological Sciences, King's College London, London, UK
| | - Federico Formenti
- Centre for Human and Applied Physiological Sciences, King's College London, London, UK
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Department of Biomechanics, University of Nebraska Omaha, Omaha, NB, USA
| | - Ross D Pollock
- Centre for Human and Applied Physiological Sciences, King's College London, London, UK
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2
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Mildren RL, Cullen KE. Vestibular Contributions to Primate Neck Postural Muscle Activity during Natural Motion. J Neurosci 2023; 43:2326-2337. [PMID: 36801822 PMCID: PMC10072293 DOI: 10.1523/jneurosci.1831-22.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 01/10/2023] [Accepted: 02/13/2023] [Indexed: 02/19/2023] Open
Abstract
To maintain stable posture of the head and body during our everyday activities, the brain integrates information across multiple sensory systems. Here, we examined how the primate vestibular system, independently and in combination with visual sensory input, contributes to the sensorimotor control of head posture across the range of dynamic motion experienced during daily life. We recorded activity of single motor units in the splenius capitis and sternocleidomastoid muscles in rhesus monkeys during yaw rotations spanning the physiological range of self-motion (up to 20 Hz) in darkness. Splenius capitis motor unit responses continued to increase with frequency up to 16 Hz in normal animals, and were strikingly absent following bilateral peripheral vestibular loss. To determine whether visual information modulated these vestibular-driven neck muscle responses, we experimentally controlled the correspondence between visual and vestibular cues of self-motion. Surprisingly, visual information did not influence motor unit responses in normal animals, nor did it substitute for absent vestibular feedback following bilateral peripheral vestibular loss. A comparison of muscle activity evoked by broadband versus sinusoidal head motion further revealed that low-frequency responses were attenuated when low- and high-frequency self-motion were experienced concurrently. Finally, we found that vestibular-evoked responses were enhanced by increased autonomic arousal, quantified via pupil size. Together, our findings directly establish the vestibular system's contribution to the sensorimotor control of head posture across the dynamic motion range experienced during everyday activities, as well as how vestibular, visual, and autonomic inputs are integrated for postural control.SIGNIFICANCE STATEMENT Our sensory systems enable us to maintain control of our posture and balance as we move through the world. Notably, the vestibular system senses motion of the head and sends motor commands, via vestibulospinal pathways, to axial and limb muscles to stabilize posture. By recording the activity of single motor units, here we show, for the first time, that the vestibular system contributes to the sensorimotor control of head posture across the dynamic motion range experienced during everyday activities. Our results further establish how vestibular, autonomic, and visual inputs are integrated for postural control. This information is essential for understanding both the mechanisms underlying the control of posture and balance, and the impact of the loss of sensory function.
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Affiliation(s)
- Robyn L Mildren
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205
| | - Kathleen E Cullen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205
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3
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Wackym PA, Balaban CD, Van Osch OJ, Morris BT, Tamakloe MA, Salvatore VL, Duwadi S, Gay JD, Mowery TM. New model of superior semicircular canal dehiscence with reversible diagnostic findings characteristic of patients with the disorder. Front Neurol 2023; 13:1035478. [PMID: 36742050 PMCID: PMC9892720 DOI: 10.3389/fneur.2022.1035478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 11/15/2022] [Indexed: 01/20/2023] Open
Abstract
Background Third window syndrome is a vestibular-cochlear disorder in humans in which a third mobile window of the otic capsule creates changes to the flow of sound pressure energy through the perilymph/endolymph. The nature and location of this third mobile window can occur at many different sites (or multiple sites); however, the most common third mobile window is superior semicircular canal dehiscence (SSCD). There are two essential objective diagnostic characteristics needed to validate a model of SSCD: the creation of a pseudoconductive hearing loss and cVEMP increased amplitude and decreased threshold. Methods Adult Mongolian gerbils (n = 36) received surgical fenestration of the superior semicircular canal of the left inner ear. ABR and c+VEMP testing were carried out prior to surgery and over acute (small 1 mm SSCD, 1-10 days) or prolonged (large 2 mm SSCD, 28 days) recovery. Because recovery of function occurred quickly, condenser brightfield stereomicroscopic examination of the dehiscence site was carried out for the small SSCD animals post-hoc and compared to both ABRs and c+VEMPs. Micro-CT analysis was also completed with representative samples of control, day 3 and 10 post-SSCD animals. Results The SSCD created a significant worsening of hearing thresholds of the left ear; especially in the lower frequency domain (1-4 kHz). Left (EXP)/right (CTL) ear comparisons via ABR show significant worsening thresholds at the same frequency representations, which is a proxy for the human pseudoconductive hearing loss seen in SSCD. For the c+VEMP measurements, increased amplitude of the sound-induced response (N1 2.5 ms and P1 3.2 ms) was observed in animals that received larger fenestrations. As the bone regrew, the c+VEMP and ABR responses returned toward preoperative values. For small SSCD animals, micro-CT data show that progressive osteoneogenesis results in resurfacing of the SSCD without bony obliteration. Conclusion The large (2 mm) SSCD used in our gerbil model results in similar electrophysiologic findings observed in patients with SSCD. The changes observed also reverse and return to baseline as the SSCD heals by bone resurfacing (with the lumen intact). Hence, this model does not require a second surgical procedure to plug the SSCD.
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Affiliation(s)
- P. Ashley Wackym
- Department of Otolaryngology – Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States,Rutgers Brain Health Institute, New Brunswick, NJ, United States
| | - Carey D. Balaban
- Departments of Otolaryngology, Neurobiology, Communication Sciences and Disorders, Bioengineering and Mechanical Engineering and Materials Science, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Olivia J. Van Osch
- Department of Otolaryngology – Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States
| | - Brian T. Morris
- Department of Otolaryngology – Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States
| | - Mark-Avery Tamakloe
- Department of Otolaryngology – Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States
| | - Victoria L. Salvatore
- Department of Otolaryngology – Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States
| | - Sudan Duwadi
- Department of Otolaryngology – Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States
| | - Jennifer D. Gay
- Department of Otolaryngology – Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States
| | - Todd M. Mowery
- Department of Otolaryngology – Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States,Rutgers Brain Health Institute, New Brunswick, NJ, United States,*Correspondence: Todd M. Mowery ✉
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4
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Gordon KA, Baitz J, Gnanasegaram JJ, McKnight C, Corneil BD, Camp AJ, Cushing SL. Response characteristics of vestibular evoked myogenic potentials recorded over splenius capitis in young adults and adolescents. ACTA OTORRINOLARINGOLOGICA ESPANOLA 2022; 73:164-176. [DOI: 10.1016/j.otoeng.2021.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 01/02/2021] [Indexed: 11/30/2022]
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5
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Gordon KA, Baitz J, Gnanasegaram JJ, McKnight C, Corneil BD, Camp AJ, Cushing SL. Response characteristics of vestibular evoked myogenic potentials recorded over splenius capitis in young adults and adolescents. ACTA OTORRINOLARINGOLOGICA ESPANOLA 2021; 73:S0001-6519(21)00038-8. [PMID: 34088494 DOI: 10.1016/j.otorri.2021.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 12/30/2020] [Accepted: 01/02/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND AND OBJECTIVES Examine vestibular evoked myogenic potential (VEMP) responses recorded from surface electrodes over Splenius Capitis (SPC) in a seated position. SPECIFIC AIMS (1) validate response characteristics of VEMP recordings from surface electrodes over Sternocleidomastoid (SCM) and over SCP and (2) assess age effects on responses in adolescents and young adults. MATERIALS AND METHODS Simultaneous surface VEMP was recorded bilaterally from electrodes placed over the dorsal neck musculature at a location known from previous work to record from SPC in 15 healthy participants during trials with head rotation toward and away from the stimulated ear. VEMP was also recorded from electrodes over SCM, ipsilateral to the stimulus ear, in the same participants in a supine, head lift/turn position. RESULTS Response amplitudes significantly increased with contraction strength and decreased with age. Participants were able to maintain sufficient contraction strength (amplitude) with head rotation to reliably measure over SPC. Normalized response amplitudes measured from electrodes over contralateral SPC were largest with head rotation contralateral to the stimulus ear. Normalized amplitudes and peak latencies were comparable to the same measures from SCM obtained in supine, head lift/turn position. CONCLUSIONS Otolith generated myogenic responses can be recorded seated from electrodes over the dorsal neck with head rotation contralateral to the stimulus ear. In this position, contralateral recordings are consistent with responses known from previous work to arise from SPC; ipsilateral recordings may include crosstalk from activated muscles nearby, including ipsilateral SCM. Overall, techniques targeting contralateral SPC during contralateral head turn may provide additional methods of recording VEMPs.
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Affiliation(s)
- Karen A Gordon
- Archie's Cochlear Implant Laboratory, Hospital for Sick Children, Toronto, ON, Canada; Department of Communication Disorders, Hospital for Sick Children, Toronto, ON, Canada; Department of Otolaryngology Head and Neck Surgery, Hospital for Sick Children, Toronto, ON, Canada; Department of Otolaryngology Head and Neck Surgery, University of Toronto, Toronto, ON, Canada; Institute of Medical Science, University of Toronto, Toronto, ON, Canada.
| | - Joshua Baitz
- Archie's Cochlear Implant Laboratory, Hospital for Sick Children, Toronto, ON, Canada
| | - Joshua J Gnanasegaram
- Archie's Cochlear Implant Laboratory, Hospital for Sick Children, Toronto, ON, Canada; Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Carmen McKnight
- Archie's Cochlear Implant Laboratory, Hospital for Sick Children, Toronto, ON, Canada
| | - Brian D Corneil
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada; Department of Psychology, University of Western Ontario, London, ON, Canada; Robarts Research Institute, University of Western Ontario, London, ON, Canada
| | - Aaron J Camp
- Discipline of Biomedical Science, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Sharon L Cushing
- Archie's Cochlear Implant Laboratory, Hospital for Sick Children, Toronto, ON, Canada; Department of Otolaryngology Head and Neck Surgery, Hospital for Sick Children, Toronto, ON, Canada; Department of Otolaryngology Head and Neck Surgery, University of Toronto, Toronto, ON, Canada; Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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Colebatch JG, Rosengren SM. Investigating short latency subcortical vestibular projections in humans: what have we learned? J Neurophysiol 2019; 122:2000-2015. [PMID: 31596627 DOI: 10.1152/jn.00157.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Vestibular evoked myogenic potentials (VEMPs) are now widely used for the noninvasive assessment of vestibular function and diagnosis in humans. This review focuses on the origin, properties, and mechanisms of cervical VEMPs and ocular VEMPs; how these reflexes relate to reports of vestibular projections to brain stem and cervical targets; and the physiological role of (otolithic) cervical and ocular reflexes. The evidence suggests that both VEMPs are likely to represent the effects of excitation of irregularly firing otolith afferents. While the air-conducted cervical VEMP appears to mainly arise from excitation of saccular receptors, the ocular VEMP evoked by bone-conducted stimulation, including impulsive bone-conducted stimuli, mainly arises from utricular afferents. The surface responses are generated by brief changes in motor unit firing. The effects that have been demonstrated are likely to represent otolith-dependent vestibulocollic and vestibulo-ocular reflexes, both linear and torsional. These observations add to previous reports of short latency otolith projections to the target muscles in the neck (sternocleidomastoid and splenius) and extraocular muscles (the inferior oblique). New insights have been provided by the investigation and application of these techniques.
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Affiliation(s)
- James G Colebatch
- Prince of Wales Hospital Clinical School, University of New South Wales, Sydney, New South Wales, Australia.,Neuroscience Research Australia, University of New South Wales, Sydney, New South Wales, Australia
| | - Sally M Rosengren
- Department of Neurology, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.,Central Clinical School, The University of Sydney, Sydney, New South Wales, Australia
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Splenius capitis: sensitive target for the cVEMP in older and neurodegenerative patients. Eur Arch Otorhinolaryngol 2019; 276:2991-3003. [DOI: 10.1007/s00405-019-05582-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 07/22/2019] [Indexed: 01/09/2023]
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Rosengren SM, Weber KP, Govender S, Welgampola MS, Dennis DL, Colebatch JG. Sound-evoked vestibular projections to the splenius capitis in humans: comparison with the sternocleidomastoid muscle. J Appl Physiol (1985) 2019; 126:1619-1629. [DOI: 10.1152/japplphysiol.00711.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The short-latency vestibulo-collic reflex in humans is well defined for only the sternocleidomastoid (SCM) neck muscle. However, other neck muscles also receive input from the balance organs and participate in neck stabilization. We therefore investigated the sound-evoked vestibular projection to the splenius capitis (SC) muscles by comparing surface and single motor unit responses in the SC and SCM muscles in 10 normal volunteers. We also recorded surface responses in patients with unilateral vestibular loss but preserved hearing and hearing loss but preserved vestibular function. The single motor unit responses were predominantly inhibitory, and the strongest responses were recorded in the contralateral SC and ipsilateral SCM. In both cases there was a significant decrease or gap in single motor unit activity, in SC at 11.7 ms for 46/66 units and in SCM at 12.7 ms for 51/58 motor units. There were fewer significant responses in the ipsilateral SC and contralateral SCM muscles, and they consisted primarily of weak increases in activity. Surface responses recorded over the contralateral SC were positive-negative during neck rotation, similar to the ipsilateral cervical vestibular evoked myogenic potential in SCM. Responses in SC were present in the patients with hearing loss and absent in the patient with vestibular loss, confirming their vestibular origin. The results describe a pattern of inhibition consistent with the synergistic relationship between these muscles for axial head rotation, with the crossed vestibular projection to the contralateral SC being weaker than the ipsilateral projection to the SCM. NEW & NOTEWORTHY We used acoustic vestibular stimulation to investigate the saccular projections to the splenius capitis (SC) and sternocleidomastoid (SCM) muscles in humans. Single motor unit recordings from within the muscles demonstrated strong inhibitory projections to the contralateral SC and ipsilateral SCM muscles and weak excitatory projections to the opposite muscle pair. This synergistic pattern of activation is consistent with a role for the reflex in axial rotation of the head.
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Affiliation(s)
- Sally M. Rosengren
- Neurology Department, Royal Prince Alfred Hospital, Camperdown, Australia
- Central Clinical School, University of Sydney, Sydney, Australia
| | - Konrad P. Weber
- Department of Neurology, University Hospital Zurich, University of Zurich, Switzerland
- Department of Ophthalmology, University Hospital Zurich, University of Zurich, Switzerland
| | - Sendhil Govender
- Prince of Wales Clinical School and Neuroscience Research Australia, University of New South Wales, Sydney, Australia
| | | | - Danielle L. Dennis
- Prince of Wales Clinical School and Neuroscience Research Australia, University of New South Wales, Sydney, Australia
| | - James G. Colebatch
- Prince of Wales Clinical School and Neuroscience Research Australia, University of New South Wales, Sydney, Australia
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Todd NPM, Govender S, Colebatch JG. Vestibular cerebellar evoked potentials in humans and their modulation during optokinetic stimulation. J Neurophysiol 2018; 120:3099-3109. [DOI: 10.1152/jn.00502.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
We recorded evoked potentials (EPs) from over the posterior fossa and in parallel ocular vestibular evoked myogenic potentials (OVEMPs) during visuo-vestibular stimulation in a sample of 7 male and 11 female human subjects. In 9 of the 18 subjects we were able to record EPs reliably in the form of an early biphasic positive-negative wave with latencies ~12 and 17 ms ipsilateral to head acceleration direction (P12-N17) and a slightly later, contralateral, biphasic positive-negative wave with latencies ~19 and 23 ms (P19-N23). The amplitudes of the responses varied widely between subjects. Both P12 and N23 EPs were modulated by the mode of visual stimulation, larger for vection (sense of movement) compared with optokinetic nystagmus and for congruent movement. We suggest that the EPs measured over the posterior fossa are a manifestation of climbing fiber responses of cerebellar cortical Purkinje cells, i.e., a form of vestibular cerebellar EP (VsCEP). The two subject groups with and without VsCEPs were distinguished by the magnitude of their OVEMPs and their subjective experience of vection. The modulation of VsCEPs by visual context may be a manifestation of cerebellar control of linear vestibular ocular reflex gain. NEW & NOTEWORTHY We report likely vestibular cerebellar evoked potentials (VsCEPs) produced by lateral head impulses recorded in intact humans over the posterior fossa. VsCEPs occurred as short-latency P12-N17 waves ipsilateral to the direction of head motion and as P19-N23 contralaterally and were present in half our subjects. Their properties suggest that the VsCEPs may be of a climbing-fiber origin. VsCEPs are related to the perception of motion and, possibly, control of linear vestibular ocular reflex gain.
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Affiliation(s)
- Neil P. M. Todd
- Department of Psychology, University of Exeter, United Kingdom
| | - Sendhil Govender
- Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales, Australia
- Neuroscience Research Australia, University of New South Wales, Sydney, New South Wales, Australia
| | - James G. Colebatch
- Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales, Australia
- Neuroscience Research Australia, University of New South Wales, Sydney, New South Wales, Australia
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10
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Forbes PA, Fice JB, Siegmund GP, Blouin JS. Electrical Vestibular Stimuli Evoke Robust Muscle Activity in Deep and Superficial Neck Muscles in Humans. Front Neurol 2018; 9:535. [PMID: 30026725 PMCID: PMC6041388 DOI: 10.3389/fneur.2018.00535] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/18/2018] [Indexed: 01/01/2023] Open
Abstract
Neck muscle activity evoked by vestibular stimuli is a clinical measure for evaluating the function of the vestibular apparatus. Cervical vestibular-evoked myogenic potentials (cVEMP) are most commonly measured in the sternocleidomastoid muscle (and more recently the splenius capitis muscle) in response to air-conducted sound, bone-conducted vibration or electrical vestibular stimuli. It is currently unknown, however, whether and how other neck muscles respond to vestibular stimuli. Here we measured activity bilaterally in the sternocleidomastoid, splenius capitis, sternohyoid, semispinalis capitis, multifidus, rectus capitis posterior, and obliquus capitis inferior using indwelling electrodes in two subjects exposed to binaural bipolar electrical vestibular stimuli. All recorded neck muscles responded to the electrical vestibular stimuli (0–100 Hz) provided they were active. Furthermore, the evoked responses were inverted on either side of the neck, consistent with a coordinated contribution of all left-right muscle pairs acting as antagonists in response to the electrically-evoked vestibular error of head motion. Overall, our results suggest that, as previously observed in cat neck muscles, broad connections exist between the human vestibular system and neck motoneurons and highlight the need for future investigations to establish their neural connections.
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Affiliation(s)
- Patrick A Forbes
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, Netherlands.,Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, Netherlands
| | - Jason B Fice
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Gunter P Siegmund
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.,MEA Forensic Engineers & Scientists, Richmond, BC, Canada
| | - Jean-Sébastien Blouin
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Institute for Computing, Information and Cognitive Systems, University of British Columbia, Vancouver, BC, Canada
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Rosengren SM, Colebatch JG. The Contributions of Vestibular Evoked Myogenic Potentials and Acoustic Vestibular Stimulation to Our Understanding of the Vestibular System. Front Neurol 2018; 9:481. [PMID: 30013504 PMCID: PMC6037197 DOI: 10.3389/fneur.2018.00481] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 06/04/2018] [Indexed: 12/16/2022] Open
Abstract
Vestibular-evoked myogenic potentials (VEMPs) are short-latency muscle reflexes typically recorded from the neck or eye muscles with surface electrodes. They are used clinically to assess otolith function, but are also interesting as they can provide information about the vestibular system and its activation by sound and vibration. Since the introduction of VEMPs more than 25 years ago, VEMPs have inspired animal and human research on the effects of acoustic vestibular stimulation on the vestibular organs, their projections and the postural muscles involved in vestibular reflexes. Using a combination of recording techniques, including single motor unit recordings, VEMP studies have enhanced our understanding of the excitability changes underlying the sound-evoked vestibulo-collic and vestibulo-ocular reflexes. Studies in patients with diseases of the vestibular system, such as superior canal dehiscence and Meniere's disease, have shown how acoustic vestibular stimulation is affected by physical changes in the vestibule, and how sound-evoked reflexes can detect these changes and their resolution in clinical contexts. This review outlines the advances in our understanding of the vestibular system that have occurred following the renewed interest in sound and vibration as a result of the VEMP.
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Affiliation(s)
- Sally M Rosengren
- Neurology Department, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.,Central Clinical School, The University of Sydney, Sydney, NSW, Australia
| | - James G Colebatch
- Prince of Wales Hospital Clinical School and Neuroscience Research Australia, University of New South Wales, Sydney, NSW, Australia
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12
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Corneil BD, Camp AJ. Animal Models of Vestibular Evoked Myogenic Potentials: The Past, Present, and Future. Front Neurol 2018; 9:489. [PMID: 29988517 PMCID: PMC6026641 DOI: 10.3389/fneur.2018.00489] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 06/05/2018] [Indexed: 11/13/2022] Open
Abstract
Vestibular-evoked myogenic potentials (VEMPs) provide a simple and cost-effective means to assess the patency of vestibular reflexes. VEMP testing constitutes a core screening method in a clinical battery that probes vestibular function. The confidence one has in interpreting the results arising from VEMP testing is linked to a fundamental understanding of the underlying functional anatomy and physiology. In this review, we will summarize the key role that studies across a range of animal models have fulfilled in contributing to this understanding, covering key findings regarding the mechanisms of excitation in the sensory periphery, the processing of sensory information in central networks, and the distribution of reflexive output to the motor periphery. Although VEMPs are often touted for their simplicity, work in animals models have emphasized how vestibular reflexes operate within a broader behavioral and functional context, and as such vestibular reflexes are influenced by multisensory integration, governed by task demands, and follow principles of muscle recruitment. We will conclude with considerations of future questions, and the ways in which studies in current and emerging animal models can contribute to further use and refinement of this test for both basic and clinical research purposes.
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Affiliation(s)
- Brian D. Corneil
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
- Department of Psychology, University of Western Ontario, London, ON, Canada
- Robarts Research Institute, University of Western Ontario, London, ON, Canada
| | - Aaron J. Camp
- Discipline of Biomedical Science, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
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13
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Govender S, Colebatch JG. Location and phase effects for ocular and cervical vestibular-evoked myogenic potentials evoked by bone-conducted stimuli at midline skull sites. J Neurophysiol 2017; 119:1045-1056. [PMID: 29357475 DOI: 10.1152/jn.00695.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Our object was to investigate the effect of location and phase on the properties of oVEMPs and cVEMPs evoked by two bone conducted (BC) stimuli, 500 Hz and an impulsive stimulus for midline skull sites from Nz to Iz, in normal volunteers. Compressive and rarefactive onset phases were used and the induced linear and rotational accelerations measured. We confirmed our previous finding of marked changes in the polarity of oVEMPs with location. For cVEMPs using the 500Hz stimulus there were few changes with location or phase, but the impulsive stimulus showed clear phase-related changes at several locations, with the shortest latencies occurring with compressive stimuli at AFz and Fz and the largest amplitudes at Iz. For oVEMPs, both stimuli showed clear effects of phase, with the shortest latencies with compressive stimuli at AFz and Fz and with the largest negativity at Oz or Iz. Whereas the effectiveness at Iz is consistent with a role in the linear VOR, the inversion of polarity and shorter latency around AFz and Fz is not and could not be explained by changes in acceleration of the head. The latency for BC 500Hz oVEMPs for AFz was the same as that for air-conducted (AC) stimuli. We suggest that whereas BC stimuli at most sites work through displacement of the otolith membrane, BC oVEMPs evoked at AFz and Fz may work through a direct action on utricular hair cells. Our findings have implications for clinical testing of VEMPs using midline BC stimuli. NEW & NOTEWORTHY We investigated VEMPs evoked from multiple midline skull sites. Large oVEMP responses were obtained with compressive stimuli at Iz, consistent with a role in the linear VOR, but we also showed inversion of polarity and the shortest latency for stimuli given at AFz and Fz. We propose that BC stimuli given at AFz and Fz may have a direct effect on otolith hair cells, whereas at other sites they work through displacement of the otolith membrane.
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Affiliation(s)
- Sendhil Govender
- Prince of Wales Clinical School and Neuroscience Research Australia, University of New South Wales, Randwick, Sydney, New South Wales , Australia
| | - James G Colebatch
- Prince of Wales Clinical School and Neuroscience Research Australia, University of New South Wales, Randwick, Sydney, New South Wales , Australia
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