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Simon MV, Rutkove SB, Ngo L, Fehnel CR, Das AS, Sarge T, Bose S, Selim M, Kumar S. Understanding the variability of the electrophysiologic laryngeal adductor reflex. Clin Neurophysiol 2024; 162:141-150. [PMID: 38631074 DOI: 10.1016/j.clinph.2024.03.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 03/11/2024] [Accepted: 03/16/2024] [Indexed: 04/19/2024]
Abstract
OBJECTIVE The laryngeal adductor reflex (LAR) is vital for airway protection and can be electrophysiologically obtained under intravenous general anesthesia (IGA). This makes the electrophysiologic LAR (eLAR) an important tool for monitoring of the vagus nerves and relevant brainstem circuitry during high-risk surgeries. We investigated the intra-class variability of normal and expected abnormal eLAR. METHODS Repeated measures of contralateral R1 (cR1) were performed under IGA in 58 patients. Data on presence/absence of cR2 and potential confounders were also collected. Review of neuroimaging, pathology and clinical exam, allowed classification into normal and expected abnormal eLAR groups. Using univariate and multivariate analysis we studied the variability of cR1 parameters and their differences between the two groups. RESULTS In both groups, cR1 latencies had coefficients of variation of <2%. In the abnormal group, cR1 had longer latencies, required higher activation currents and was more frequently desynchronized and unsustained; cR2 was more frequently absent. CONCLUSIONS cR1 latencies show high analytical precision for measurements. Delayed onset, difficult to elicit, desynchronized and unsustained cR1, and absence of cR2 signal an abnormal eLAR. SIGNIFICANCE Understanding the variability and behavior of normal and abnormal eLAR under IGA can aid in the interpretation of its changes during monitoring.
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Affiliation(s)
- Mirela V Simon
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.
| | - Seward B Rutkove
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Long Ngo
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Corey R Fehnel
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Alvin S Das
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Todd Sarge
- Department of Anesthesia, Beth Israel Deaconess Medical Center, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Somnath Bose
- Department of Anesthesia, Beth Israel Deaconess Medical Center, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Magdy Selim
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Sandeep Kumar
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
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Rangarajan V, Schreiber JJ, Barragan B, Schaefer SY, Honeycutt CF. Delays in the Reticulospinal System Are Associated With a Reduced Capacity to Learn a Simulated Feeding Task in Older Adults. Front Neural Circuits 2022; 15:681706. [PMID: 35153677 PMCID: PMC8829385 DOI: 10.3389/fncir.2021.681706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 12/15/2021] [Indexed: 11/13/2022] Open
Abstract
Learning declines with age. Recent evidence indicates that the brainstem may play an important role in learning and motor skill acquisition. Our objective was to determine if delays in the reticular formation, measured via the startle reflex, correspond to age-related deficits in learning and retention. We hypothesized that delays in the startle reflex would be linearly correlated to learning and retention deficits in older adults. To determine if associations were unique to the reticulospinal system, we also evaluated corticospinal contributions with transcranial magnetic stimulation. Our results showed a linear relationship between startle onset latency and percent learning and retention but no relationship between active or passive motor-evoked potential onsets or peak-to-peak amplitude. These results lay the foundation for further study to evaluate if (1) the reticular formation is a subcortical facilitator of skill acquisition and (2) processing delays in the reticular formation contribute to age-related learning deficits.
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Rothwell J, Antal A, Burke D, Carlsen A, Georgiev D, Jahanshahi M, Sternad D, Valls-Solé J, Ziemann U. Central nervous system physiology. Clin Neurophysiol 2021; 132:3043-3083. [PMID: 34717225 PMCID: PMC8863401 DOI: 10.1016/j.clinph.2021.09.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 09/13/2021] [Accepted: 09/20/2021] [Indexed: 12/15/2022]
Abstract
This is the second chapter of the series on the use of clinical neurophysiology for the study of movement disorders. It focusses on methods that can be used to probe neural circuits in brain and spinal cord. These include use of spinal and supraspinal reflexes to probe the integrity of transmission in specific pathways; transcranial methods of brain stimulation such as transcranial magnetic stimulation and transcranial direct current stimulation, which activate or modulate (respectively) the activity of populations of central neurones; EEG methods, both in conjunction with brain stimulation or with behavioural measures that record the activity of populations of central neurones; and pure behavioural measures that allow us to build conceptual models of motor control. The methods are discussed mainly in relation to work on healthy individuals. Later chapters will focus specifically on changes caused by pathology.
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Affiliation(s)
- John Rothwell
- Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London, UK,Corresponding author at: Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK, (J. Rothwell)
| | - Andrea Antal
- Department of Neurology, University Medical Center Göttingen, Germany
| | - David Burke
- Department of Neurology, Royal Prince Alfred Hospital, University of Sydney, Sydney 2050, Australia
| | - Antony Carlsen
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Dejan Georgiev
- Department of Neurology, University Medical Centre Ljubljana, Slovenia
| | - Marjan Jahanshahi
- Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London, UK
| | - Dagmar Sternad
- Departments of Biology, Electrical & Computer Engineering, and Physics, Northeastern University, Boston, MA 02115, USA
| | - Josep Valls-Solé
- Institut d’Investigació Biomèdica August Pi I Sunyer, Villarroel, 170, Barcelona, Spain
| | - Ulf Ziemann
- Department of Neurology and Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University, Tübingen, Germany
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Valls-Solé J, Castellote JM, Kofler M, Serranová T, Versace V, Campostrini S, Campolo M. When reflex reactions oppose voluntary commands: The StartReact effect on eye opening. Psychophysiology 2020; 58:e13752. [PMID: 33347635 DOI: 10.1111/psyp.13752] [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: 08/24/2020] [Revised: 11/08/2020] [Accepted: 11/23/2020] [Indexed: 11/27/2022]
Abstract
A startling auditory stimulus (SAS) induces a reflex response involving, among other reactions, a strong contraction of the orbicularis oculi muscle (OOc) and subsequent eye closure. A SAS also induces the StartReact effect, a significant shortening of reaction time in subjects ready for task execution. We examined the obvious conflict appearing when a StartReact paradigm requires participants with eyes closed to open their eyes to look for a visual target. We recorded OOc EMG activity and eyelid movements in healthy volunteers who were instructed to open their eyes at perception of a somatosensory imperative stimulus (IS) and locate the position of a Libet's clock's hand shown on a computer screen at 80 cm distance. In 6 out of 20 trials, we delivered a SAS simultaneously with the IS. The main outcome measures were reaction time at onset of eyelid movement and the time gap (TG) separating subjective assessment of the clock's hand position from real IS issuing. Control experiments included reaction time to eye closing and target location with eyes open to the same IS. Reaction time was significantly faster in SAS than in noSAS trials and slower for eye opening than for eye closing in both conditions. In the eye-opening task, TG was significantly shorter in SAS with respect to noSAS trials, despite the presence of the SAS-related burst in the OOc before EMG cessation. Our results indicate that the StartReact effect speeds up eye opening and location of a target in the visual field despite the startle reaction opposing the task.
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Affiliation(s)
- Josep Valls-Solé
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Barcelona, Spain
| | - Juan M Castellote
- Department of Radiology, Rehabilitation and Physiotherapy, School of Medicine, National School of Occupational Medicine, Carlos III Institute of Health, Madrid, Spain.,Complutense University of Madrid, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Markus Kofler
- Department of Neurology, Hochzirl Hospital, Zirl, Austria
| | - Tereza Serranová
- Department of Neurology and Centre of Clinical Neuroscience, 1st Medical Faculty, Charles University, Prague, Czech Republic
| | - Viviana Versace
- Department of Neurorehabilitation, Hospital of Vipiteno/Sterzing, Vipiteno/Sterzing, Italy.,Reasearch Unit for Neurorehabilitation of South Tyrol, Bolzano/Bozen, Italy
| | - Stefania Campostrini
- Department of Neurorehabilitation, Hospital of Vipiteno/Sterzing, Vipiteno/Sterzing, Italy.,Reasearch Unit for Neurorehabilitation of South Tyrol, Bolzano/Bozen, Italy
| | - Michela Campolo
- EMG and Motor Control Unit, Neurology Department, Hospital Clínic, University of Barcelona, Barcelona, Spain
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Prepulse Inhibition of the Auditory Startle Reflex Assessment as a Hallmark of Brainstem Sensorimotor Gating Mechanisms. Brain Sci 2020; 10:brainsci10090639. [PMID: 32947873 PMCID: PMC7563436 DOI: 10.3390/brainsci10090639] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/09/2020] [Accepted: 09/14/2020] [Indexed: 12/20/2022] Open
Abstract
When a low-salience stimulus of any type of sensory modality-auditory, visual, tactile-immediately precedes an unexpected startle-like stimulus, such as the acoustic startle reflex, the startle motor reaction becomes less pronounced or is even abolished. This phenomenon is known as prepulse inhibition (PPI), and it provides a quantitative measure of central processing by filtering out irrelevant stimuli. As PPI implies plasticity of a reflex and is related to automatic or attentional processes, depending on the interstimulus intervals, this behavioral paradigm might be considered a potential marker of short- and long-term plasticity. Assessment of PPI is directly related to the examination of neural sensorimotor gating mechanisms, which are plastic-adaptive operations for preventing overstimulation and helping the brain to focus on a specific stimulus among other distracters. Despite their obvious importance in normal brain activity, little is known about the intimate physiology, circuitry, and neurochemistry of sensorimotor gating mechanisms. In this work, we extensively review the current literature focusing on studies that used state-of-the-art techniques to interrogate the neuroanatomy, connectomics, neurotransmitter-receptor functions, and sex-derived differences in the PPI process, and how we can harness it as biological marker in neurological and psychiatric pathology.
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Gündüz A, Ayas S, Kofler M, Aydın Ş, Kızıltan ME. Modulation of the excitatory phase following the cutaneous silent period by vibration. Neurol Sci 2020; 42:633-637. [PMID: 32648049 DOI: 10.1007/s10072-020-04557-5] [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: 01/21/2020] [Accepted: 07/02/2020] [Indexed: 10/23/2022]
Abstract
INTRODUCTION The post-inhibition excitatory phase (E3) of the cutaneous silent period (CSP) is attributed to the resynchronization of motoneuron activity following the inhibitory period but there is also evidence that a somatosensory startle reflex may contribute to this phase. We hypothesized that the startle reflex component contained in E3 will decrease during vibration. METHODS Sixteen healthy individuals were included in the study. CSP was recorded from slightly contracted right thenar muscles after painful index finger stimulation, before, during, and immediately after vibration. The values of the percentage change of E3 relative to pre-stimulus baseline (E3%) were compared before, during, and after vibration for each individual. RESULTS There was a reduction in E3% during vibration and the values returned to normal immediately after vibration (153.1 ± 43.5%, 115.2 ± 30.2%, 154.9 ± 68.2%, respectively; p = 0.030). DISCUSSION E3 is reduced during vibration in healthy individuals, presumably due to suppression of a reflex component, which is superimposed upon the known resynchronization of motoneurons.
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Affiliation(s)
- Ayşegül Gündüz
- Department of Neurology, Cerrahpasa School of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Selahattin Ayas
- Department of Neurology, Cerrahpasa School of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey.
| | - Markus Kofler
- Department of Neurology, Hochzirl Hospital, Zirl, Austria
| | - Şenay Aydın
- Department of Neurology, Cerrahpasa School of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Meral Erdemir Kızıltan
- Department of Neurology, Cerrahpasa School of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
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Jafari Z, Kolb BE, Mohajerani MH. Prepulse inhibition of the acoustic startle reflex and P50 gating in aging and alzheimer's disease. Ageing Res Rev 2020; 59:101028. [PMID: 32092463 DOI: 10.1016/j.arr.2020.101028] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 01/20/2020] [Accepted: 02/17/2020] [Indexed: 02/07/2023]
Abstract
Inhibition plays a crucial role in many functional domains, such as cognition, emotion, and actions. Studies on cognitive aging demonstrate changes in inhibitory mechanisms are age- and pathology-related. Prepulse inhibition (PPI) is the suppression of an acoustic startle reflex (ASR) to an intense stimulus when a weak prepulse stimulus precedes the startle stimulus. A reduction of PPI is thought to reflect dysfunction of sensorimotor gating which normally suppresses excessive behavioral responses to disruptive stimuli. Both human and rodent studies show age-dependent alterations of PPI of the ASR that are further compromised in Alzheimer's disease (AD). The auditory P50 gating, an index of repetition suppression, also is characterized as a putative electrophysiological biomarker of prodromal AD. This review provides the latest evidence of age- and AD-associated impairment of sensorimotor gating based upon both human and rodent studies, as well as the AD-related disruption of P50 gating in humans. It begins with a concise review of neural networks underlying PPI regulation. Then, evidence of age- and AD-related dysfunction of both PPI and P50 gating is discussed. The attentional/ emotional aspects of sensorimotor gating and the neurotransmitter mechanisms underpinning PPI and P50 gating are also reviewed. The review ends with conclusions and research directions.
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Affiliation(s)
- Zahra Jafari
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, T1K 3M4 AB, Canada; Department of Basic Sciences in Rehabilitation, School of Rehabilitation Sciences, Iran University of Medical Science (IUMS), Tehran, Iran
| | - Bryan E Kolb
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, T1K 3M4 AB, Canada.
| | - Majid H Mohajerani
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, T1K 3M4 AB, Canada.
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Sanders O, Hsiao HY, Savin DN, Creath RA, Rogers MW. Aging changes in protective balance and startle responses to sudden drop perturbations. J Neurophysiol 2019; 122:39-50. [PMID: 31017835 PMCID: PMC6689787 DOI: 10.1152/jn.00431.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 04/05/2019] [Accepted: 04/17/2019] [Indexed: 01/25/2023] Open
Abstract
This study investigated aging changes in protective balance and startle responses to sudden drop perturbations and their effect on landing impact forces (vertical ground reaction forces, vGRF) and balance stability. Twelve healthy older (6 men; mean age = 72.5 ± 2.32 yr, mean ± SE) and 12 younger adults (7 men; mean age = 28.09 ± 1.03 yr) stood atop a moveable platform and received externally triggered drop perturbations of the support surface. Electromyographic activity was recorded bilaterally over the sternocleidomastoid (SCM), middle deltoid, biceps brachii, vastus lateralis (VL), biceps femoris (BF), medial gastrocnemius (MG), and tibialis anterior (TA). Whole body kinematics were recorded with motion analysis. Stability in the anteroposterior direction was quantified using the margin of stability (MoS). Incidence of early onset of bilateral SCM activation within 120 ms after drop onset was present during the first-trial response (FTR) for all participants. Co-contraction indexes during FTRs between VL and BF as well as TA and MG were significantly greater in the older group (VL/BF by 26%, P < 0.05; TA/MG by 37%, P < 0.05). Reduced shoulder abduction between FTR and last-trial responses, indicative of habituation, was present across both groups. Significant age-related differences in landing strategy were present between groups, because older adults had greater trunk flexion (P < 0.05) and less knee flexion (P < 0.05) that resulted in greater peak vGRFs and decreased MoS compared with younger adults. These findings suggest age-associated abnormalities of delayed, exaggerated, and poorly habituated startle/postural FTRs are linked with greater landing impact force and diminished balance stabilization. NEW & NOTEWORTHY This study investigated the role of startle as a pathophysiological mechanism contributing to balance impairment in aging. We measured neuromotor responses as younger and older adults stood on a platform that dropped unexpectedly. Group differences in landing strategies indicated age-associated abnormalities of delayed, exaggerated, and poorly habituated startle/postural responses linked with a higher magnitude of impact force and decreased balance stabilization. The findings have implications for determining mechanisms contributing to falls and related injuries.
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Affiliation(s)
- Ozell Sanders
- Division of Rehabilitation Medicine, The Children's Hospital of Philadelphia , Philadelphia, Pennsylvania
| | - Hao Yuan Hsiao
- Department of Kinesiology and Health Education, University of Texas at Austin , Austin, Texas
| | - Douglas N Savin
- Department of Physical Therapy and Rehabilitation Science, University of Maryland School of Medicine, Baltimore, Maryland
| | - Robert A Creath
- Department of Physical Therapy and Rehabilitation Science, University of Maryland School of Medicine, Baltimore, Maryland
| | - Mark W Rogers
- Department of Physical Therapy and Rehabilitation Science, University of Maryland School of Medicine, Baltimore, Maryland
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Aging effects of motor prediction on protective balance and startle responses to sudden drop perturbations. J Biomech 2019; 91:23-31. [PMID: 31128842 DOI: 10.1016/j.jbiomech.2019.05.005] [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] [Received: 08/21/2018] [Revised: 04/17/2019] [Accepted: 05/03/2019] [Indexed: 11/20/2022]
Abstract
This pilot study investigated the effect of age on the ability of motor prediction during self-triggered drop perturbations (SLF) to modulate startle-like first trial response (FTR) magnitude during externally-triggered (EXT) drop perturbations. Ten healthy older (71.4 ± 1.44 years) and younger adults (26.2 ± 1.63 years) stood atop a moveable platform and received blocks of twelve consecutive EXT and SLF drop perturbations. Following the last SLF trial, participants received an additional EXT trial spaced 20 min apart to assess retention (EXT RTN) of any modulation effects. Electromyographic (EMG) activity was recorded bilaterally over the sternocleidomastoid (SCM), vastus lateralis (VL), biceps femoris (BF), medial gastrocnemius (MG), and tibialis anterior (TA). Whole-body kinematics and kinetic data were recorded. Stability in the antero-posterior direction was quantified using the margin of stability (MoS). Compared with EXT trials, both groups reduced SCM peak amplitude responses during SLF and EXT RTN trials. VL/BF and TA/MG coactivation were reduced during SLF FTR compared to EXT FTR (p < 0.05) with reduced peak vertical ground reaction forces (vGRF) in both younger and older adults (p < 0.05). Older adults increased their MoS during SLF FTR compared to EXT FTR (p < 0.05). Both groups performed more eccentric work during SLF trials compared to EXT (p < 0.05). These findings indicate that abnormal startle effects with aging may interfere with balance recovery and increase risk of injury with external balance perturbations. Motor prediction may be used to acutely mitigate abnormal startle/postural responses with aging.
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Evidence for Startle Effects due to Externally Induced Lower Limb Movements: Implications in Neurorehabilitation. BIOMED RESEARCH INTERNATIONAL 2017; 2017:8471546. [PMID: 28299334 PMCID: PMC5337331 DOI: 10.1155/2017/8471546] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 01/10/2017] [Accepted: 01/19/2017] [Indexed: 11/17/2022]
Abstract
Passive limb displacement is routinely used to assess muscle tone. If we attempt to quantify muscle stiffness using mechanical devices, it is important to know whether kinematic stimuli are able to trigger startle reactions. Whether kinematic stimuli are able to elicit a startle reflex and to accelerate prepared voluntary movements (StartReact effect) has not been studied extensively to date. Eleven healthy subjects were suspended in an exoskeleton and were exposed to passive left knee flexion (KF) at three intensities, occasionally replaced by fast right KF. Upon perceiving the movement subjects were asked to perform right wrist extension (WE), assessed by extensor carpi radialis (ECR) electromyographic activity. ECR latencies were shortest in fast trials. Startle responses were present in most fast trials, yet being significantly accelerated and larger with right versus left KF, since the former occurred less frequently and thus less expectedly. Startle responses were associated with earlier and larger ECR responses (StartReact effect), with the largest effect again upon right KF. The results provide evidence that kinematic stimuli are able to elicit both startle reflexes and a StartReact effect, which depend on stimulus intensity and anticipation, as well as on the subjects' preparedness to respond.
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Le Duc J, Fournier P, Hébert S. Modulation of Prepulse Inhibition and Startle Reflex by Emotions: A Comparison between Young and Older Adults. Front Aging Neurosci 2016; 8:33. [PMID: 26941643 PMCID: PMC4763063 DOI: 10.3389/fnagi.2016.00033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 02/09/2016] [Indexed: 12/22/2022] Open
Abstract
This study examined whether or not the acoustic startle response and sensorimotor gating may be modulated by emotions differentially between young and older adults. Two groups of participants (mean age Young: 24 years old; Elderly: 63.6 years old) were presented with three types of auditory stimuli (Startle alone, High or Low frequency Prepulse) while viewing pleasant, neutral, or unpleasant images. Electromyographic activity of the eyeblink response was measured. Results show that older adults displayed diminished eyeblink responses whereas younger adults displayed enhanced eyeblink responses when viewing negative images. Sensorimotor gating also differed between young and older adults, with enhanced sensorimotor gating abilities while viewing positive pictures in older adults and diminished abilities while viewing negative pictures among younger adults. These results argue in favor of a differential emotional influence on the sensorimotor abilities of young and older adults, with a positivity bias among the latter.
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Affiliation(s)
- Jolyanne Le Duc
- School of Speech Pathology and Audiology, Faculty of Medicine, Université de MontréalMontréal, QC, Canada; BRAMS, International Laboratory for Research on Brain, Music, and Sound, Université de MontréalMontréal, QC, Canada; CRIUGM, Centre de Recherche de l'Institut Universitaire de Gériatrie de MontréalMontréal, QC, Canada
| | - Philippe Fournier
- School of Speech Pathology and Audiology, Faculty of Medicine, Université de MontréalMontréal, QC, Canada; BRAMS, International Laboratory for Research on Brain, Music, and Sound, Université de MontréalMontréal, QC, Canada; CRIUGM, Centre de Recherche de l'Institut Universitaire de Gériatrie de MontréalMontréal, QC, Canada
| | - Sylvie Hébert
- School of Speech Pathology and Audiology, Faculty of Medicine, Université de MontréalMontréal, QC, Canada; BRAMS, International Laboratory for Research on Brain, Music, and Sound, Université de MontréalMontréal, QC, Canada; CRIUGM, Centre de Recherche de l'Institut Universitaire de Gériatrie de MontréalMontréal, QC, Canada
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Mota IA, Fernandes JB, Cardoso MN, Sala-Blanch X, Kofler M, Valls-Solé J. Temporal profile of the effects of regional anesthesia on the cutaneous reflexes of foot muscles. Exp Brain Res 2015; 233:2587-96. [PMID: 26025613 DOI: 10.1007/s00221-015-4329-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 05/14/2015] [Indexed: 12/23/2022]
Abstract
We analyzed the effects of an anesthetic sciatic nerve block on the cutaneomuscular reflex (cMR) and the cutaneous silent period (cSP) of foot muscles, in order to investigate further the type of fibers involved in their generation. In 14 neurologically normal patients with indication for surgical treatment of hallux valgus, we recorded from the extensor digitorum brevis muscle the reflex responses elicited by high-intensity electrical stimulation of the big toe at various time periods, ranging from 0 to 20 min, after ultrasound-guided sciatic nerve popliteal anesthetic block. The first effect was a delay in cSP onset latency, with no changes in end latency. The cMR remained unaltered up to when subjects were no longer able to maintain the contraction. The effects of local anesthetics on peripheral nerves allow for recognition of the different types of fibers contributing to the cMR and the cSP in muscles of the lower limb.
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Affiliation(s)
- Isabella A Mota
- Hospital Universitario Lauro Wanderley, João Pessoa, Paraiba, Brazil
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13
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Tresch UA, Perreault EJ, Honeycutt CF. Startle evoked movement is delayed in older adults: implications for brainstem processing in the elderly. Physiol Rep 2014; 2:2/6/e12025. [PMID: 24907294 PMCID: PMC4208637 DOI: 10.14814/phy2.12025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Little attention has been given to how age affects the neural processing of movement within the brainstem. Since the brainstem plays a critical role in motor control throughout the whole body, having a clear understanding of deficits in brainstem function could provide important insights into movement deficits in older adults. A unique property of the startle reflex is its ability to involuntarily elicit planned movements, a phenomenon referred to as startReact. The noninvasive startReact response has previously been used to probe both brainstem utilization and motor planning. Our objective was to evaluate deficits in startReact hand extension movements in older adults. We hypothesized that startReact hand extension will be intact but delayed. Electromyography was recorded from the sternocleidomastoid (SCM) muscle to detect startle and the extensor digitorum communis (EDC) to quantify movement onset in both young (24 ± 1) and older adults (70 ± 11). Subjects were exposed to a startling loud sound when prepared to extend their hand. Trials were split into those where a startle did (SCM+) and did not (SCM−) occur. We found that startReact was intact but delayed in older adults. SCM+ onset latencies were faster than SCM− trials in both the populations, however, SCM+ onset latencies were slower in older adults compared to young (Δ = 8 msec). We conclude that the observed age‐related delay in the startReact response most likely arises from central processing delays within the brainstem. Our objective was to utilize the noninvasive startReact phenomenon, which is mediated through the brainstem, to gain insight into brainstem processing in older adults. We found that startReact hand extension was intact but delayed in older adults. The observed age‐related delay in the startReact response most likely arises from central processing delays within the brainstem. Our result that the startReact response is delayed in older individuals highlights that movements (e.g., posture, locomotion) and reflexes (e.g., long‐latency stretch reflexes) that are coordinated by the brainstem may have similar deficits in older adults.
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Affiliation(s)
| | - Eric J Perreault
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, Illinois Department of Biomedical Engineering, Northwestern University, Evanston, Illinois Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, Illinois
| | - Claire F Honeycutt
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, Illinois
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Grashow R, Miller MW, McKinney A, Nie LH, Sparrow D, Hu H, Weisskopf MG. Lead exposure and fear-potentiated startle in the VA Normative Aging Study: a pilot study of a novel physiological approach to investigating neurotoxicant effects. Neurotoxicol Teratol 2013; 38:21-8. [PMID: 23603705 DOI: 10.1016/j.ntt.2013.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 04/05/2013] [Accepted: 04/08/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND Physiologically-based indicators of neural plasticity in humans could provide mechanistic insights into toxicant actions on learning in the brain, and perhaps prove more objective and sensitive measures of such effects than other methods. OBJECTIVES We explored the association between lead exposure and classical conditioning of the acoustic startle reflex (ASR)-a simple form of associative learning in the brain-in a population of elderly men. Fifty-one men from the VA Normative Aging Study with cumulative bone lead exposure measurements made with K-X-Ray-Fluorescence participated in a fear-conditioning protocol. RESULTS The mean age of the men was 75.5years (standard deviation [sd]=5.9) and mean patella lead concentration was 22.7μg/g bone (sd=15.9). Baseline ASR eyeblink response decreased with age, but was not associated with subsequent conditioning. Among 37 men with valid responses at the end of the protocol, higher patella lead was associated with decreased awareness of the conditioning contingency (declarative learning; adjusted odds ratio [OR] per 20μg/g patella lead=0.91, 95% confidence interval [CI]: 0.84, 0.99, p=0.03). Eyeblink conditioning (non-declarative learning) was 0.44sd less (95% CI: -0.91, 0.02; p=0.06) per 20μg/g patella lead after adjustment. Each result was stronger when correcting for the interval between lead measurement and startle testing (awareness: OR=0.88, 95% CI: 0.78, 0.99, p=0.04; conditioning: -0.79sd less, 95% CI: -1.56, 0.03, p=0.04). CONCLUSIONS This initial exploration suggests that lead exposure interferes with specific neural mechanisms of learning and offers the possibility that the ASR may provide a new approach to physiologically explore the effects of neurotoxicant exposures on neural mechanisms of learning in humans with a paradigm that is directly comparable to animal models.
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Affiliation(s)
- Rachel Grashow
- Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA.
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15
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Bakker MJ, van Dijk JG, Pramono A, Sutarni S, Tijssen MA. Latah: An indonesian startle syndrome. Mov Disord 2013; 28:370-9. [DOI: 10.1002/mds.25280] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2011] [Revised: 09/29/2012] [Accepted: 10/17/2012] [Indexed: 11/09/2022] Open
Affiliation(s)
- Mirte J. Bakker
- Department of Neurology and Clinical Neurophysiology; Academic Medical Centre; University of Amsterdam; Amsterdam the Netherlands
- Department of Clinical and Health Psychology; University of Utrecht; Utrecht the Netherlands
| | - J. Gert van Dijk
- Department of Neurology and Clinical Neurophysiology; Leiden University Medical Centre; Leiden the Netherlands
| | - Astuti Pramono
- Neuropediatric Department; Sardjito General Hospital; Gadjah Mada University; Jogjakarta Indonesia
| | - Sri Sutarni
- Neuropediatric Department; Sardjito General Hospital; Gadjah Mada University; Jogjakarta Indonesia
| | - Marina A.J. Tijssen
- Department of Neurology and Clinical Neurophysiology; Academic Medical Centre; University of Amsterdam; Amsterdam the Netherlands
- Department of Neurology; University Medical Centre Groningen (UMCG); University of Groningen; Groningen the Netherlands
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16
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Blink reflex prepulse inhibition and excitability recovery: Influence of age and sex. Clin Neurophysiol 2013; 124:126-35. [DOI: 10.1016/j.clinph.2012.07.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2012] [Revised: 06/06/2012] [Accepted: 07/02/2012] [Indexed: 11/21/2022]
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17
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Dreissen YE, Bakker MJ, Koelman JH, Tijssen MA. Exaggerated startle reactions. Clin Neurophysiol 2012; 123:34-44. [DOI: 10.1016/j.clinph.2011.09.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 08/31/2011] [Accepted: 09/03/2011] [Indexed: 11/15/2022]
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18
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Kim SG, Chung MK, Schaefer SM, van Reekum C, Davidson RJ. Sparse Shape Representation using the Laplace-Beltrami Eigenfunctions and Its Application to Modeling Subcortical Structures. PROCEEDINGS. WORKSHOP ON MATHEMATICAL METHODS IN BIOMEDICAL IMAGE ANALYSIS 2012:25-32. [PMID: 23783079 DOI: 10.1109/mmbia.2012.6164736] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We present a new sparse shape modeling framework on the Laplace-Beltrami (LB) eigenfunctions. Traditionally, the LB-eigenfunctions are used as a basis for intrinsically representing surface shapes by forming a Fourier series expansion. To reduce high frequency noise, only the first few terms are used in the expansion and higher frequency terms are simply thrown away. However, some lower frequency terms may not necessarily contribute significantly in reconstructing the surfaces. Motivated by this idea, we propose to filter out only the significant eigenfunctions by imposing l1-penalty. The new sparse framework can further avoid additional surface-based smoothing often used in the field. The proposed approach is applied in investigating the influence of age (38-79 years) and gender on amygdala and hippocampus shapes in the normal population. In addition, we show how the emotional response is related to the anatomy of the subcortical structures.
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Affiliation(s)
- Seung-Goo Kim
- Department of Brain and Cognitive Sciences, Seoul National University, Korea
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19
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Normalization of the auditory startle reflex after symptom reduction in children with anxiety disorders. J Psychiatr Res 2011; 45:796-802. [PMID: 21131005 DOI: 10.1016/j.jpsychires.2010.11.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Revised: 10/26/2010] [Accepted: 11/03/2010] [Indexed: 11/20/2022]
Abstract
BACKGROUND In an earlier study the Auditory Startle Response (ASR) of anxiety disordered (AD) children proved to be enlarged. This study examines in a controlled design to what extent this increase is responsive to symptom reduction during Cognitive Behavioral Therapy (CBT) METHODS: The activity of 6 muscles following 104 dB tones in 20 patients (M = 12,7 years; SD = 2.5) and 25 matched controls was measured with an electromyogram (EMG). In addition, the sympathetic skin response was investigated. Response to treatment was investigated with the Anxiety Disorder Interview Schedule for Children (ADIS-C) and the Spence Children's Anxiety Scale (SCAS). RESULTS Treatment responders (n = 12) showed a significant ASR decrease over time, whereas non-responders (n = 8) showed a significant ASR increase or no significant ASR difference. In controls, the ASR was not significantly different at follow up compared to baseline. The sympathetic skin response was stable in controls and treatment responders but significantly increased over time in treatment non-responders. Linear regression suggested that one of the ASR pre-treatment parameters (multiple muscle EMG magnitude) predicts treatment response. CONCLUSIONS The ASR decreases in AD children when anxiety symptoms diminish. In addition, the ASR may be useful in predicting response to CBT in AD children.
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Carlsen AN, Maslovat D, Lam MY, Chua R, Franks IM. Considerations for the use of a startling acoustic stimulus in studies of motor preparation in humans. Neurosci Biobehav Rev 2010; 35:366-76. [PMID: 20466020 DOI: 10.1016/j.neubiorev.2010.04.009] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 04/27/2010] [Accepted: 04/29/2010] [Indexed: 11/25/2022]
Abstract
Recent studies have used a loud (> 120 dB) startle-eliciting acoustic stimulus as a probe to investigate early motor response preparation in humans. The use of a startle in these studies has provided insight into not only the neurophysiological substrates underlying motor preparation, but also into the behavioural response strategies associated with particular stimulus-response sets. However, as the use of startle as a probe for preparation is a relatively new technique, a standard protocol within the context of movement paradigms does not yet exist. Here we review the recent literature using startle as a probe during the preparation phase of movement tasks, with an emphasis on how the experimental parameters affect the results obtained. Additionally, an overview of the literature surrounding the startle stimulus parameters is provided, and factors affecting the startle response are considered. In particular, we provide a review of the factors that should be taken into consideration when using a startling stimulus in human research.
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Affiliation(s)
- Anthony N Carlsen
- School of Human Kinetics, University of British Columbia, Vancouver, Canada.
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21
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Bakker MJ, Boer F, Benninga MA, Koelman JHTM, Tijssen MAJ. Increased auditory startle reflex in children with functional abdominal pain. J Pediatr 2010; 156:285-91.e1. [PMID: 19846112 DOI: 10.1016/j.jpeds.2009.08.045] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 06/11/2009] [Accepted: 08/21/2009] [Indexed: 01/20/2023]
Abstract
OBJECTIVE To test the hypothesis that children with abdominal pain-related functional gastrointestinal disorders have a general hypersensitivity for sensory stimuli. STUDY DESIGN Auditory startle reflexes were assessed in 20 children classified according to Rome III classifications of abdominal pain-related functional gastrointestinal disorders (13 irritable bowel syndrome [IBS], 7 functional abdominal pain syndrome; mean age, 12.4 years; 15 girls) and 23 control subjects (14 girls; mean age, 12.3 years) using a case-control design. The activity of 6 left-sided muscles and the sympathetic skin response were obtained by an electromyogram. We presented sudden loud noises to the subjects through headphones. RESULTS Both the combined response of 6 muscles and the blink response proved to be significantly increased in patients with abdominal pain compared with control subjects. A significant increase of the sympathetic skin response was not found. Comorbid anxiety disorders (8 patients with abdominal pain) or Rome III subclassification did not significantly affect these results. CONCLUSIONS This study demonstrates an objective hyperresponsivity to nongastrointestinal stimuli. Children with abdominal pain-related functional gastrointestinal disorders may have a generalized hypersensitivity of the central nervous system.
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Affiliation(s)
- Mirte J Bakker
- Department of Neurology and Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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22
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The startle reaction to somatosensory inputs: different response pattern to stimuli of upper and lower limbs. Exp Brain Res 2009; 195:285-92. [DOI: 10.1007/s00221-009-1784-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Accepted: 03/24/2009] [Indexed: 10/20/2022]
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23
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Bakker MJ, Boer F, van der Meer JN, Koelman JH, Boerée T, Bour L, Tijssen MA. Quantification of the auditory startle reflex in children. Clin Neurophysiol 2009; 120:424-30. [DOI: 10.1016/j.clinph.2008.11.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Revised: 09/23/2008] [Accepted: 11/03/2008] [Indexed: 10/21/2022]
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24
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Kumru H, Opisso E, Valls-Solé J, Kofler M. The effect of a prepulse stimulus on the EMG rebound following the cutaneous silent period. J Physiol 2008; 587:587-95. [PMID: 19064615 DOI: 10.1113/jphysiol.2008.164186] [Citation(s) in RCA: 29] [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 cutaneous silent period (CSP) is a spinal inhibitory reflex mediated by Adelta fibres. The postinhibitory rebound of electromyographic (EMG) activity following the CSP has been mainly attributed to resynchronization of motoneurons, but the possibility of startle reflex activity contributing to the EMG burst has also been suggested. Several types of reflexes may be suppressed by a preceding weak stimulus--a phenomenon called prepulse inhibition (PPI). Our aim was to study whether PPI would diminish the EMG rebound, thereby providing further evidence for excitatory reflex activity contained within the postinhibitory EMG rebound following the CSP. Ten healthy subjects underwent CSP testing following noxious digit II stimulation in two conditions, with and without a prepulse applied to digit III. Rectified surface EMG recordings were obtained from right orbicularis oculi, sternocleidomastoid and thenar muscles of the dominant hand during thumb abduction with 25% of maximum force. The area of the EMG rebound and the EMG reflex responses in orbicularis oculi and sternocleidomastoid were significantly smaller in recordings where a prepulse stimulus was applied 100 ms before the stimulus as compared to control responses without prepulse. CSP onset and end latency, CSP duration, and the degree of EMG suppression were not influenced. Prepulses significantly reduced subjective discomfort as based on visual analog scale scores. Inhibition of the EMG rebound by prepulse stimulation supports the hypothesis that the excitatory EMG activity following the CSP contains not only resynchronization of motoneuronal firing, but also an excitatory reflex component. The most probable type of reflex seems to be a somatosensory startle reflex, a defence reaction which is generated in structures located in the caudal brainstem following an unexpected intense stimulus. Reduction of the discomfort associated with high-intensity electrical fingertip stimulation by a prepulse without affecting CSP parameters underlines the utility of PPI in the context of CSP testing.
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Affiliation(s)
- H Kumru
- Department of Neurology, Instituto Guttmann, Hospital de Neurorehabilitació, Camí de Can Ruti S/N, Badalona, Spain
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25
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Valls-Solé J, Kumru H, Kofler M. Interaction between startle and voluntary reactions in humans. Exp Brain Res 2008; 187:497-507. [DOI: 10.1007/s00221-008-1402-0] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2007] [Accepted: 04/19/2008] [Indexed: 01/07/2023]
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26
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Laterality of auditory startle responses in humans. Clin Neurophysiol 2008; 119:309-14. [DOI: 10.1016/j.clinph.2007.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2007] [Revised: 10/30/2007] [Accepted: 11/11/2007] [Indexed: 11/23/2022]
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27
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Luef GJ, Löscher WN. The effect of levetiracetam in startle disease. J Neurol 2007; 254:808-9. [PMID: 17401745 DOI: 10.1007/s00415-006-0437-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2006] [Revised: 09/21/2006] [Accepted: 10/10/2006] [Indexed: 10/23/2022]
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28
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Müller J, Rinnerthaler M, Poewe W, Kofler M. Auditory startle reaction in primary blepharospasm. Mov Disord 2007; 22:268-72. [PMID: 17149731 DOI: 10.1002/mds.21270] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Primary dystonia is associated with abnormal brainstem function, as shown by abnormalities of the blink reflex in blepharospasm (BSP) and of the auditory startle reaction in cervical dystonia. We examined the auditory startle reaction--a brainstem reflex elicited by an unexpected loud stimulus--in patients with primary BSP to expand knowledge on brainstem pathophysiology in primary focal dystonia. Thirteen patients with primary BSP were included and 13 age- and sex-matched healthy volunteers served as controls. Auditory startle responses (ASRs) were elicited by binaural high-intensity auditory stimuli, and reflex electromyographic activity was recorded simultaneously with surface electrodes bilaterally from masseter, orbicularis oculi, sternocleidomastoid, and biceps brachii muscles. Patients with BSP showed higher ASR probabilities (masseter, sternocleidomastoid, biceps brachii), shorter ASR onset latencies (masseter, orbicularis oculi, sternocleidomastoid), and larger ASR area-under-the-curve (masseter, sternocleidomastoid) as compared with normal controls. Habituation of ASRs did not differ significantly between patients and controls. These results corroborate previous findings of increased brainstem excitability in primary BSP but point to a different pattern of brainstem dysfunction compared to cervical dystonia, indicating that different pathophysiological mechanisms are involved in the two types of focal dystonia.
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Affiliation(s)
- Jörg Müller
- Department of Neurology, Medical University Innsbruck, Austria
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29
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Kumru H, Urra X, Compta Y, Castellote JM, Turbau J, Valls-Solé J. Excitability of subcortical motor circuits in Go/noGo and forced choice reaction time tasks. Neurosci Lett 2006; 406:66-70. [PMID: 16904825 DOI: 10.1016/j.neulet.2006.07.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 06/16/2006] [Accepted: 07/06/2006] [Indexed: 11/17/2022]
Abstract
The size of the response to a startling auditory stimulus (SAS) may reflect the excitability of the reticulospinal tract. In this study, we examined whether there was any excitability change in the reticulospinal tract during preparation for execution of two types of choice reaction time task: a forced choice reaction time task (fCRT) and a Go/no-Go task (GnG). In 13 healthy volunteers we used three types of trials: control trials in which subjects were requested to perform ballistic wrist movements during fCRT or GnG tasks; test trials in which a SAS was presented with the visual cue, and baseline trials in which SAS was presented alone. Latency and area of the responses to SAS were measured in the orbicularis oculi and in the sternocleidomastoid (SCM) muscles. The results obtained in baseline trials were used to calculate the mean resting baseline excitability level of the reticulospinal tract for each individual, and the values obtained in test trials were expressed as percentages of mean baseline for normalization of data from all individuals. The area of the responses to SAS in SCM was significantly larger in fCRT than in GnG (p=0.002). There was a significant shortening of reaction time in test trials that was inversely correlated with area of SCM (p<0.05). We conclude that the subcortical motor tracts activated by SAS are more excitable during fCRT tasks than GnG tasks. Changing the excitability of subcortical motor structures may be a strategy used by the central nervous system in motor control that is selected according to the motor program.
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Affiliation(s)
- Hatice Kumru
- Unitat d'EMG, Servei de Neurologia, Hospital Clinic, Facultad de Medicina, Universitat de Barcelona, IDIBAPS (Institut d'Investigació Biomèdica August Pi i Sunyer), Villarroel 170, Barcelona 08036, Spain.
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30
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Castellote JM, Kumru H, Queralt A, Valls-Solé J. A startle speeds up the execution of externally guided saccades. Exp Brain Res 2006; 177:129-36. [PMID: 16944110 DOI: 10.1007/s00221-006-0659-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Accepted: 07/26/2006] [Indexed: 10/24/2022]
Abstract
The control of eye movements depends in part on subcortical motor centres. Gaze is often directed towards salient visual stimuli of our environment with no conscious voluntary commands. To further understand to what extent preprogrammed eye movements can be triggered subcortically, we carried out a study in normal volunteers to examine the effects of a startling auditory stimulus (SAS) on externally guided saccades. A peripheral visual cue was presented in the horizontal plane at a site distant 15 degrees from the fixation point, and subjects were instructed to make a saccade to it. SAS was presented together with the peripheral visual cue in 20% of trials. To force rapid visual fixation at the end of the saccade, targets were loaded with a second cue, a small arrow pointing towards the right or the left (or a neutral sign), not distinguishable with peripheral vision. Subjects were requested to perform a flexion/extension wrist movement, according to the direction of the arrow (or not to move if the second cue was the neutral sign). SAS presented together with the visual target caused a significant shortening of the latency of saccadic movements. The wrist movements performed as a response to the second cue had similar reaction times regardless of whether the trial contained a SAS or not. Our results show that voluntary saccades to peripheral targets are speeded up by activation of the startle circuit, and that this effect does not cause a significant disturbance in the execution of simple in-target cues. These results suggest that subcortical structures play a main role in preparation of externally guided saccades.
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Affiliation(s)
- Juan M Castellote
- Facultad de Ciencias de la Actividad Física y el Deporte, Universidad de Valencia, 46010, Valencia, Spain
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31
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Abstract
Startle syndromes consist of three heterogeneous groups of disorders with abnormal responses to startling events. The first is hyperekplexia, which can be split up into the "major" or "minor" form. The major form of hyperekplexia is characterised by excessive startle reflexes, startle-induced falls, and continuous stiffness in the neonatal period. This form has a genetic basis: mutations in the alpha1 subunit of the glycine receptor gene, GLRA1, or related genes. The minor form, which is restricted to excessive startle reflexes with no stiffness, has no known genetic cause or underlying pathophysiological substrate. The second group of startle syndromes are neuropsychiatric, in which excessive startling and various additional behavioural features occur. The third group are disorders in which startling stimuli can induce responses other than startle reflexes, such as startle-induced epilepsy. Diagnosis of startle syndromes depends on clinical history, electromyographic studies, and genetic screening. Further study of these disorders may enable improved discrimination between the different groups.
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Affiliation(s)
- Mirte J Bakker
- Department of Neurology, Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
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32
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Siegelaar SE, Olff M, Bour LJ, Veelo D, Zwinderman AH, van Bruggen G, de Vries GJ, Raabe S, Cupido C, Koelman JHTM, Tijssen MAJ. The auditory startle response in post-traumatic stress disorder. Exp Brain Res 2006; 174:1-6. [PMID: 16525797 DOI: 10.1007/s00221-006-0413-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2005] [Accepted: 01/24/2006] [Indexed: 10/24/2022]
Abstract
Post-traumatic stress disorder (PTSD) patients are considered to have excessive EMG responses in the orbicularis oculi (OO) muscle and excessive autonomic responses to startling stimuli. The aim of the present study was to gain more insight into the pattern of the generalized auditory startle reflex (ASR). Reflex EMG responses to auditory startling stimuli in seven muscles rather than the EMG response of the OO alone as well as the psychogalvanic reflex (PGR) were studied in PTSD patients and healthy controls. Ten subjects with chronic PTSD (>3 months) and a history of excessive startling and 11 healthy controls were included. Latency, amplitude and duration of the EMG responses and the amplitude of the PGR to 10 auditory stimuli of 110 dB SPL were investigated in seven left-sided muscles. The size of the startle reflex, defined by the number of muscles activated by the acoustic stimulus and by the amplitude of the EMG response of the OO muscle as well, did not differ significantly between patients and controls. Median latencies of activity in the sternocleidomastoid (SC) (patients 80 ms; controls 54 ms) and the deltoid (DE) muscles (patients 113 ms; controls 69 ms) were prolonged significantly in PTSD compared to controls (P < 0.05). In the OO muscle, a late response (median latency in patients 308 ms; in controls 522 ms), probably the orienting reflex, was more frequently present in patients (56%) than in controls (12%). In patients, the mean PGR was enlarged compared to controls (P < 0.05). The size of the ASR response is not enlarged in PTSD patients. EMG latencies in the PTSD patients are prolonged in SC and DE muscles. The presence of a late response in the OO muscle discriminates between groups of PTSD patients with a history of startling and healthy controls. In addition, the autonomic response, i.e. the enlarged amplitude of the PGR can discriminate between these groups.
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Affiliation(s)
- S E Siegelaar
- Department of Neurology H2-222 and Clinical Neurophysiology, Academic Medical Centre, PO Box 22660, 1100 DD, Amsterdam, The Netherlands
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Kofler M, Müller J, Valls-Solé J. Chapter 19 Auditory startle responses as a probe of brainstem function in healthy subjects and patients with movement disorders. SUPPLEMENTS TO CLINICAL NEUROPHYSIOLOGY 2006; 58:232-48. [PMID: 16623335 DOI: 10.1016/s1567-424x(09)70072-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Markus Kofler
- Department of Neurology, Hospital HochZirl, A-6170 Zirl, Austria.
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Abstract
Posthypoxic coma is often associated with cortical and brainstem hyperexcitability. Five months following cardiopulmonary resuscitation after myocardial infarction and ventricular arrhythmia, a 47-year-old man presented with posthypoxic cerebral dysfunction, minimal responsiveness, severe spastic-dystonic tetraparesis, and stimulus-sensitive muscle spasms upon acoustic and sensory stimulation. Neurophysiological examination revealed increased long-loop reflexes in abductor pollicis brevis muscle following median nerve stimulation at the wrist, consistent with cortical hyperexcitability. Exaggerated startle responses provided evidence of concomitant brainstem disinhibition. Levetiracetam up to 3,000 mg per day suppressed transcortical long-loop reflexes in a dose-dependent manner without concomitant suppression of the H-reflex and only mild attenuation of the startle response. The present findings suggest a suppressive effect of levetiracetam on cortical neurons in the absence of a spinal effect on monosynaptic reflexes, and thus support the drug's efficacy in posthypoxic cortical hyperexcitability.
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Affiliation(s)
- Markus Kofler
- Department of Neurology, Hospital Hochzirl, A-6170 Zirl, Austria.
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35
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Kofler M, Poustka K. Ipsi- and contralateral exteroceptive EMG modulation in uni- and bilaterally activated thenar muscles. Clin Neurophysiol 2005; 116:300-7. [PMID: 15661108 DOI: 10.1016/j.clinph.2004.09.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVE The cutaneous silent period (CSP) is a spinal inhibitory reflex mediated by A-delta fibers. The exact underlying neural pathway, however, is unknown. This study was undertaken to investigate whether the neural circuitry mediating CSPs is wired unilaterally or whether there is evidence of influence from or upon the contralateral side. METHODS Fifteen healthy subjects underwent bilateral CSP testing following unilateral nociceptive digit II stimulation. Surface electromyographic (EMG) recordings were obtained bilaterally from thenar muscles following unilateral recurrent nociceptive digit II stimulation while activating the ipsilateral or the contralateral or both thenar muscles against resistance. RESULTS Nociceptive digit II stimulation evoked consistent CSPs in ipsilateral thenar muscles during voluntary contraction, while there was no consistent influence on EMG activity in contralateral thenar muscles at rest. Furthermore, nociceptive digit II stimulation did neither consistently affect EMG activity in ipsilateral thenar muscles at rest nor in contralateral thenar muscles during voluntary contraction. Finally, there was no significant difference between any CSP parameters obtained during unilateral versus bilateral muscle contraction. Occasional late excitatory EMG activity in relaxed or contracted thenar muscles resembled startle reflexes, which seem to contribute to the post-inhibition EMG-rebound. CONCLUSIONS The present findings are consistent with unilateral wiring of the spinal circuitry mediating CSPs. SIGNIFICANCE The essential lack of a crossed inhibitory influence of nociceptive digit II stimulation underscores the utility of CSP testing in the assessment of the A-delta fiber system in healthy subjects and patients with various pathologies.
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Affiliation(s)
- Markus Kofler
- Department of Neurology, Hospital Hochzirl A-6170 Zirl, Austria.
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Jurkowski AJ, Stepp E, Hackley SA. Variable foreperiod deficits in Parkinson's disease: dissociation across reflexive and voluntary behaviors. Brain Cogn 2004; 58:49-61. [PMID: 15878726 DOI: 10.1016/j.bandc.2004.09.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Indexed: 10/26/2022]
Abstract
The effect of a visual warning signal (1.0-6.5 s random foreperiod, FP) on the latency of voluntary (hand-grip) and reflexive (startle-eyeblink) reactions was investigated in Parkinson's disease (PD) patients and in young and aged control subjects. Equivalent FP effects on blink were observed across groups. By contrast, FP effects diverged for voluntary responses across groups with no effect of foreperiod duration for PD patients. The convergence of these results with findings from animal research suggests that interval-timing processes associated with higher level voluntary behaviors are dependent upon intact dopaminergic pathways, while those associated with lower level reflexive behaviors are spared in PD.
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Affiliation(s)
- Anita J Jurkowski
- Duke University Center for the Study of Aging and Human Development, Brain Imaging and Analysis Center, Box 3918, Duke University Medical Center, Durham, NC 27710, USA.
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Müller J, Kofler M, Wenning GK, Seppi K, Valls-Solé J, Poewe W. Auditory startle response in cervical dystonia. Mov Disord 2004; 18:1522-6. [PMID: 14673891 DOI: 10.1002/mds.10609] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The excitability of brainstem neurons is abnormally enhanced in patients with cervical dystonia (CD), but the extend of such abnormality is not known. We examined whether patients with CD showed abnormalities in the auditory startle response (ASR), a brainstem reflex elicited by an unexpected loud stimulus. Thirteen patients with CD were investigated 3 months after botulinum toxin treatment. Thirteen healthy volunteers served as controls. ASRs were elicited by binaural high-intensity auditory stimuli. Reflex electromyographic (EMG) activity was recorded simultaneously with surface electrodes bilaterally from masseter, orbicularis oculi, sternocleidomastoid, and biceps brachii muscles. We found that ASR onset latencies were similar for patients and controls. CD patients had significantly lower ASR probabilities than controls (P = 0.007). ASR area under the curve was significantly smaller in CD patients (P = 0.017). Similar to controls, patients showed a significant habituation of ASR (P < 0.001, each); however, CD patients showed a prolonged tonic or phasic EMG activity after the initial ASR that was not observed in controls. Normal latencies and recruitment pattern indicate a preserved organization of intrinsic neural pathways mediating ASR in CD. Reduced ASR probability and magnitude as well as prolonged EMG activity after the proper startle response corroborate and extend previous findings on brainstem dysfunction in CD.
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Affiliation(s)
- Jörg Müller
- Department of Neurology, University Hospital Innsbruck, Innsbruck, Austria
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Ludewig K, Ludewig S, Seitz A, Obrist M, Geyer MA, Vollenweider FX. The acoustic startle reflex and its modulation: effects of age and gender in humans. Biol Psychol 2003; 63:311-23. [PMID: 12853174 DOI: 10.1016/s0301-0511(03)00074-7] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The acoustic startle reflex and its modulation by prepulse inhibition (PPI) and habituation are used in many studies in different fields of neuropsychiatric research. The aim of this study was to examine the effects of age and gender on PPI, startle magnitude, and habituation in healthy human volunteers. Twenty-seven male and 28 female participants of four different age groups (range: 20-60 years) were investigated in an acoustic startle paradigm using a startle stimulus of 115 dB and a prepulse of 86 dB (16 dB over the white noise background) with five different lead intervals (30, 60, 120, 240, and 2000 ms). Seventeen males and 16 female participants were tested three times at monthly intervals. Aged participants showed significantly lower startle magnitude and significantly more habituation than younger participants, but there was no effect of age on PPI or prepulse facilitation. Moreover, there were no effects of gender on startle magnitude, PPI, prepulse facilitation, or habituation measures. Healthy males and females exhibited stable startle magnitudes and PPI across sessions. The results demonstrated that PPI and startle are reliable measures of sensory information processing in both genders and that startle magnitude and habituation are age-dependent measures.
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Affiliation(s)
- Katja Ludewig
- Psychiatric Services of Aargau Canton, Department of Research, PO Box 298, CH-5201, Brugg, Switzerland
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Kofler M, Müller J, Seppi K, Wenning GK. Exaggerated auditory startle responses in multiple system atrophy: a comparative study of parkinson and cerebellar subtypes. Clin Neurophysiol 2003; 114:541-7. [PMID: 12705434 DOI: 10.1016/s1388-2457(02)00390-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Auditory startle responses (ASRs) have recently been reported to be exaggerated in cranial and peripheral nerve supplied muscles of patients with multiple system atrophy (MSA). ASRs displayed increased probability, amplitude and duration, shorter onset latency, and reduced habituation in comparison with healthy subjects. In order to investigate whether certain ASR features may differentiate MSA subtypes, the authors studied ASRs in 21 MSA patients (olivopontocerebellar type, MSA-C: n = 8, striatonigral type, MSA-P: n = 13), and 17 age-matched normal controls. METHODS ASRs were elicited by binaural high-intensity auditory stimuli which differed randomly in tonal frequency and intensity (250 Hz, 90 db; 500 Hz, 105 db; 750 Hz, 105 db; 1000 Hz, 110 db normal hearing level), presented through tubal insert phones. Reflex electromyographic activity was simultaneously recorded with surface electrodes from masseter, orbicularis oculi, sternocleidomastoid, biceps brachii, abductor pollicis brevis, rectus femoris, tibialis anterior, and soleus muscles. RESULTS Eighteen MSA patients (86%) had exaggerated ASRs as compared to normal subjects. At group level, indices of ASR disinhibition including increased ASR probability (in extremity muscles), shortened onset latency, and enlarged response magnitude were significantly more marked in MSA-P as compared to MSA-C patients. ASR probability showed habituation in normal subjects, less in MSA-P. and none in MSA-C patients. Three MSA-patients had no ASRs except in orbicularis oculi muscle. CONCLUSIONS Although absent ASRs may occur in some MSA patients, most of them exhibit exaggerated ASRs. This finding may reflect disinhibition of lower brainstem nuclei due to the degenerative disorder. ASRs were significantly more disinhibited in MSA-P versus MSA-C. suggesting involvement of different neural structures in the two MSA-subtypes.
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Affiliation(s)
- Markus Kofler
- Department of Neurology, Hospital Hochzirl, Anna-Dengel-Haus, A-6170 Zirl, Austria.
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Schauer R, Singer M, Saltuari L, Kofler M. Suppression of cortical myoclonus by levetiracetam. Mov Disord 2002; 17:411-5. [PMID: 11921136 DOI: 10.1002/mds.10027] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
A 16-year-old boy suffered severely disabling posthypoxic myoclonus. Neurophysiological investigation showed cortical but not reticular reflex myoclonus. Add-on therapy with levetiracetam significantly improved the patient's clinical condition, suppressed cortical myoclonus-associated spikes, and enabled further neurorehabilitation.
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Affiliation(s)
- Robert Schauer
- Department of Neurology, Hospital Hochzirl, Zirl, Austria
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Abstract
The auditory startle reaction is considered a brainstem reflex in response to an unexpected loud stimulus. It may be abnormal in various neurological conditions. However, the influence of gender on physiological characteristics of auditory startle responses (ASRs) in humans has to date been studied only in orbicularis oculi muscle. We investigated 54 healthy adult subjects (27 males, 27 females). ASRs were elicited by binaural high-intensity auditory stimuli which differed randomly in tonal frequency and intensity (250 Hz-90 db; 500 Hz-105 dB; 750 Hz-110 db, 1000 Hz-110 dB nHL), presented through tubal insert phones. Reflex electromyographic activity was simultaneously recorded with surface electrodes from masseter, orbicularis oculi, sternocleidomastoid, biceps brachii, abductor pollicis brevis, rectus femoris, tibialis anterior, and soleus muscles. ASR probability was significantly lower, and ASR area under the curve was significantly smaller, in men versus women. Median onset latencies did not differ significantly, but tended to be shorter in the lower extremities of men despite greater body height. Habituation, measured as a reduction in response probability with repeated stimulation, was significant in all muscles except orbicularis oculi in both men and women. Our data provide evidence for a significant influence of gender on ASR characteristics. The observed differences are likely due to gender-specific variations of central processing in the brainstem centers involved in ASR generation, and should be taken into account when testing ASRs in health and disease.
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Affiliation(s)
- M Kofler
- Departments of Neurology, Hospital Hochzirl, A-6170 Zirl, Austria.
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