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Kofler M, Haibach M, Kofler M, Thurner M, Pucks-Faes E, Versace V. Abnormal modulation of the blink reflex in functional sensory loss. Clin Neurophysiol 2024; 162:162-164. [PMID: 38640821 DOI: 10.1016/j.clinph.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 03/29/2024] [Accepted: 04/03/2024] [Indexed: 04/21/2024]
Affiliation(s)
- Markus Kofler
- Department of Neurology, Hochzirl Hospital, Zirl, Österreich.
| | - Moritz Haibach
- Department of Neurology, Hochzirl Hospital, Zirl, Österreich
| | - Manuela Kofler
- Department of Neurology, Hochzirl Hospital, Zirl, Österreich
| | - Michael Thurner
- Department of Neurology, Hochzirl Hospital, Zirl, Österreich
| | - Elke Pucks-Faes
- Department of Neurology, Hochzirl Hospital, Zirl, Österreich
| | - Viviana Versace
- Department of Neurorehabilitation, Hospital of Vipiteno (SABES-ASDAA), Vipiteno-Sterzing, Italy
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Bologna M, Paparella G, Valls-Solé J, Hallett M, Berardelli A. Neural control of blinking. Clin Neurophysiol 2024; 161:59-68. [PMID: 38447495 DOI: 10.1016/j.clinph.2024.02.023] [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: 10/31/2023] [Revised: 02/01/2024] [Accepted: 02/07/2024] [Indexed: 03/08/2024]
Abstract
Blinking is a motor act characterized by the sequential closing and opening of the eyelids, which is achieved through the reciprocal activation of the orbicularis oculi and levator palpebrae superioris muscles. This stereotyped movement can be triggered reflexively, occur spontaneously, or voluntarily initiated. During each type of blinking, the neural control of the antagonistic interaction between the orbicularis oculi and levator palpebrae superioris muscles is governed by partially overlapping circuits distributed across cortical, subcortical, and brainstem structures. This paper provides a comprehensive overview of the anatomical and physiological foundations underlying the neural control of blinking. We describe the infra-nuclear apparatus, as well as the supra-nuclear control mechanisms, i.e., how cortical, subcortical, and brainstem structures regulate and coordinate the different types of blinking.
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Affiliation(s)
- Matteo Bologna
- Department of Human Neurosciences, Sapienza, University of Rome, Rome, Italy; IRCCS Neuromed, Pozzilli, IS, Italy.
| | - Giulia Paparella
- Department of Human Neurosciences, Sapienza, University of Rome, Rome, Italy; IRCCS Neuromed, Pozzilli, IS, Italy
| | - Josep Valls-Solé
- Institut d'Investigació Biomèdica August Pi i Sunyer, Barcelona, Spain
| | - Mark Hallett
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Alfredo Berardelli
- Department of Human Neurosciences, Sapienza, University of Rome, Rome, Italy; IRCCS Neuromed, Pozzilli, IS, Italy
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Gunduz A, Valls-Solé J, Serranová T, Coppola G, Kofler M, Jääskeläinen SK. The blink reflex and its modulation - Part 2: Pathophysiology and clinical utility. Clin Neurophysiol 2024; 160:75-94. [PMID: 38412746 DOI: 10.1016/j.clinph.2024.02.006] [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: 07/09/2023] [Revised: 12/30/2023] [Accepted: 02/06/2024] [Indexed: 02/29/2024]
Abstract
The blink reflex (BR) is integrated at the brainstem; however, it is modulated by inputs from various structures such as the striatum, globus pallidus, substantia nigra, and nucleus raphe magnus but also from afferent input from the peripheral nervous system. Therefore, it provides information about the pathophysiology of numerous peripheral and central nervous system disorders. The BR is a valuable tool for studying the integrity of the trigemino-facial system, the relevant brainstem nuclei, and circuits. At the same time, some neurophysiological techniques applying the BR may indicate abnormalities involving structures rostral to the brainstem that modulate or control the BR circuits. This is a state-of-the-art review of the clinical application of BR modulation; physiology is reviewed in part 1. In this review, we aim to present the role of the BR and techniques related to its modulation in understanding pathophysiological mechanisms of motor control and pain disorders, in which these techniques are diagnostically helpful. Furthermore, some BR techniques may have a predictive value or serve as a basis for follow-up evaluation. BR testing may benefit in the diagnosis of hemifacial spasm, dystonia, functional movement disorders, migraine, orofacial pain, and psychiatric disorders. Although the abnormalities in the integrity of the BR pathway itself may provide information about trigeminal or facial nerve disorders, alterations in BR excitability are found in several disease conditions. BR excitability studies are suitable for understanding the common pathophysiological mechanisms behind various clinical entities, elucidating alterations in top-down inhibitory systems, and allowing for follow-up and quantitation of many neurological syndromes.
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Affiliation(s)
- Aysegul Gunduz
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Neurology, Division of Neurophysiology, Istanbul, Turkey.
| | - Josep Valls-Solé
- IDIBAPS. Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villarroel 170 08024, Barcelona, Spain.
| | - Tereza Serranová
- Department of Neurology and Center of Clinical Neuroscience, Charles University, Prague 1st Faculty of Medicine and General University Hospital, Prague, Kateřinská 30, 12800 Prague 2, Czech Republic.
| | - Gianluca Coppola
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome Polo Pontino ICOT, via Franco Faggiana 1668 04100, Latina, Italy.
| | - Markus Kofler
- Department of Neurology, Hochzirl Hospital, A-6170 Zirl, Austria.
| | - Satu K Jääskeläinen
- Department of Clinical Neurophysiology, Division of Medical Imaging, Turku University Hospital and University of Turku, Postal Box 52, FIN 20521 Turku, Finland.
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Kofler M, Hallett M, Iannetti GD, Versace V, Ellrich J, Téllez MJ, Valls-Solé J. The blink reflex and its modulation - Part 1: Physiological mechanisms. Clin Neurophysiol 2024; 160:130-152. [PMID: 38102022 PMCID: PMC10978309 DOI: 10.1016/j.clinph.2023.11.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 11/11/2023] [Accepted: 11/22/2023] [Indexed: 12/17/2023]
Abstract
The blink reflex (BR) is a protective eye-closure reflex mediated by brainstem circuits. The BR is usually evoked by electrical supraorbital nerve stimulation but can be elicited by a variety of sensory modalities. It has a long history in clinical neurophysiology practice. Less is known, however, about the many ways to modulate the BR. Various neurophysiological techniques can be applied to examine different aspects of afferent and efferent BR modulation. In this line, classical conditioning, prepulse and paired-pulse stimulation, and BR elicitation by self-stimulation may serve to investigate various aspects of brainstem connectivity. The BR may be used as a tool to quantify top-down modulation based on implicit assessment of the value of blinking in a given situation, e.g., depending on changes in stimulus location and probability of occurrence. Understanding the role of non-nociceptive and nociceptive fibers in eliciting a BR is important to get insight into the underlying neural circuitry. Finally, the use of BRs and other brainstem reflexes under general anesthesia may help to advance our knowledge of the brainstem in areas not amenable in awake intact humans. This review summarizes talks held by the Brainstem Special Interest Group of the International Federation of Clinical Neurophysiology at the International Congress of Clinical Neurophysiology 2022 in Geneva, Switzerland, and provides a state-of-the-art overview of the physiology of BR modulation. Understanding the principles of BR modulation is fundamental for a valid and thoughtful clinical application (reviewed in part 2) (Gunduz et al., submitted).
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Affiliation(s)
- Markus Kofler
- Department of Neurology, Hochzirl Hospital, Zirl, Austria.
| | - Mark Hallett
- National Institute of Neurological Disorders and Stroke, NIH, USA.
| | - Gian Domenico Iannetti
- University College London, United Kingdom; Italian Institute of Technology (IIT), Rome, Italy.
| | - Viviana Versace
- Department of Neurorehabilitation, Hospital of Vipiteno (SABES-ASDAA), Teaching Hospital of the Paracelsus Medical Private University (PMU), Vipiteno-Sterzing, Italy.
| | - Jens Ellrich
- Friedrich-Alexander-University Erlangen-Nuremberg, Germany.
| | | | - Josep Valls-Solé
- IDIBAPS (Institut d'Investigació August Pi i Sunyer), University of Barcelona, Spain.
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Steinruecke M, Mason I, Keen M, McWhirter L, Carson AJ, Stone J, Hoeritzauer I. Pain and functional neurological disorder: a systematic review and meta-analysis. J Neurol Neurosurg Psychiatry 2024:jnnp-2023-332810. [PMID: 38383157 DOI: 10.1136/jnnp-2023-332810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/24/2024] [Indexed: 02/23/2024]
Abstract
BACKGROUND Functional neurological disorder (FND) is characterised by neurological symptoms, such as seizures and abnormal movements. Despite its significance to patients, the clinical features of chronic pain in people with FND, and of FND in people with chronic pain, have not been comprehensively studied. METHODS We systematically reviewed PubMed, Embase and PsycINFO for studies of chronic pain in adults with FND and FND in patients with chronic pain. We described the proportions of patients reporting pain, pain rating and timing, pain-related diagnoses and responsiveness to treatment. We performed random effects meta-analyses of the proportions of patients with FND who reported pain or were diagnosed with pain-related disorders. RESULTS Seven hundred and fifteen articles were screened and 64 were included in the analysis. Eight case-control studies of 3476 patients described pain symptoms in a higher proportion of patients with FND than controls with other neurological disorders. A random effects model of 30 cohorts found that an estimated 55% (95% CI 46% to 64%) of 4272 patients with FND reported pain. Random effects models estimated diagnoses of complex regional pain syndrome in 22% (95% CI 6% to 39%) of patients, irritable bowel syndrome in 16% (95% CI 9% to 24%) and fibromyalgia in 10% (95% CI 8% to 13%). Five studies of FND diagnoses among 361 patients with chronic pain were identified. Most interventions for FND did not ameliorate pain, even when other symptoms improved. CONCLUSIONS Pain symptoms and pain-related diagnoses are common in FND. Classification systems and treatments should routinely consider pain as a comorbidity in patients with FND.
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Affiliation(s)
| | - Isabel Mason
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Mairi Keen
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Laura McWhirter
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
- Department of Clinical Neurosciences, Royal Infirmary of Edinburgh, Edinburgh, UK
| | - Alan J Carson
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
- Department of Clinical Neurosciences, Royal Infirmary of Edinburgh, Edinburgh, UK
| | - Jon Stone
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
- Department of Clinical Neurosciences, Royal Infirmary of Edinburgh, Edinburgh, UK
| | - Ingrid Hoeritzauer
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
- Department of Clinical Neurosciences, Royal Infirmary of Edinburgh, Edinburgh, UK
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Nováková L, Anýž J, Forejtová Z, Rošíková T, Věchetová G, Sojka P, Růžička E, Serranová T. Increased Frequency of Self-Reported Obsessive-Compulsive Symptoms in Patients with Functional Movement Disorders. Mov Disord Clin Pract 2023; 10:1341-1348. [PMID: 37772279 PMCID: PMC10525059 DOI: 10.1002/mdc3.13812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 04/06/2023] [Accepted: 05/29/2023] [Indexed: 09/30/2023] Open
Abstract
Background Functional movement disorders (FMD) are associated with a high prevalence of psychiatric comorbidities. Objective To assess the frequency of obsessive-compulsive symptoms (OCS) in FMD. Methods A total of 167 consecutive patients with clinically definite FMD (mean age = 44.4 years, standard deviation [SD] = 12.0, 119 females) and 145 healthy controls (mean age = 43.2 years, SD = 11.8, 103 females) completed the Obsessive-Compulsive Inventory-Revised (OCI-R), which is a widely used tool for assessing OCS. The cutoff score ≥21 is indicative of clinically significant obsessive-compulsive disorder (OCD). Motor symptom severity was assessed using the Simplified FMD Rating Scale (S-FMDRS). All subjects completed questionnaires for depression, anxiety, pain, fatigue, cognitive complaints, health-related quality of life, and childhood trauma. Personality traits were assessed using the Big Five questionnaire. Results FMD patients had higher mean OCI-R score and higher proportion of individuals with OCI-R ≥ 21 42%, 95% confidence interval (CI) = (30.2, 54.6) versus 16%, 95% CI = (8.2, 28.2) in controls, P < 0.001. Patients had higher scores in three domains: checking, ordering, and obsessing (P < 0.001). FMD patients with OCI-R score ≥21 had higher depression, anxiety, cognitive complaints, and lower quality of life compared to those with score <21 (P < 0.001). No correlation between OCI-R and S-FMDRS scores was found. Conclusions FMD patients reported higher rates of OCS compared to controls, along with higher rates of non-motor symptoms and lower quality of life. This finding may have clinical implications and raises the possibility of shared risk factors and common pathophysiological mechanisms in FMD and OCD.
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Affiliation(s)
- Lucia Nováková
- Department of Neurology and Centre of Clinical NeuroscienceCharles University, 1st Faculty of Medicine and General University Hospital in PraguePragueCzech Republic
| | - Jiří Anýž
- Department of Cybernetics, Faculty of Electrical EngineeringCzech Technical University in PraguePragueCzech Republic
| | - Zuzana Forejtová
- Department of Neurology and Centre of Clinical NeuroscienceCharles University, 1st Faculty of Medicine and General University Hospital in PraguePragueCzech Republic
| | - Tereza Rošíková
- Department of Neurology and Centre of Clinical NeuroscienceCharles University, 1st Faculty of Medicine and General University Hospital in PraguePragueCzech Republic
| | - Gabriela Věchetová
- Department of Neurology and Centre of Clinical NeuroscienceCharles University, 1st Faculty of Medicine and General University Hospital in PraguePragueCzech Republic
| | - Petr Sojka
- Department of Neurology and Centre of Clinical NeuroscienceCharles University, 1st Faculty of Medicine and General University Hospital in PraguePragueCzech Republic
| | - Evžen Růžička
- Department of Neurology and Centre of Clinical NeuroscienceCharles University, 1st Faculty of Medicine and General University Hospital in PraguePragueCzech Republic
| | - Tereza Serranová
- Department of Neurology and Centre of Clinical NeuroscienceCharles University, 1st Faculty of Medicine and General University Hospital in PraguePragueCzech Republic
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Hao X, Huang X, Yin X, Wang HY, Lu R, Liang Z, Song C. Elucidation of the mechanism underlying impaired sensorimotor gating in patients with primary blepharospasm using prepulse inhibition. Front Neurol 2023; 14:1105483. [PMID: 36816573 PMCID: PMC9929365 DOI: 10.3389/fneur.2023.1105483] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 01/16/2023] [Indexed: 02/04/2023] Open
Abstract
Objective We aimed to analyze prepulse inhibition (PPI) impairment of the blink reflex in patients with primary blepharospasm (BSP). Methods We recruited 30 BSP patients and 20 gender- and age-matched healthy controls (HCs). Weak electrical stimulation was applied to the right index finger at interstimulus intervals (ISIs) of 120, 200, and 300 ms before the supraorbital nerve stimulation to investigate PPI size [PPI size = (1 - R2 area at prepulse trials/R2 area at baseline trials) × 100%]. Results The prepulse stimulus significantly inhibited the R 2 component at the three ISIs in both groups, but less inhibition was shown in the BSP group (p < 0.05). In HCs, the prepulse stimulus induced prolonged R 2 and R 2c latencies at the three ISIs and increased the R 1 amplitude at ISIs of 120 ms; these changes were absent in BSP patients. In the BSP group, patients with sensory tricks showed better PPI than patients without sensory tricks. Disease duration and motor symptom severity showed no significant correlation with PPI size. Conclusion In BSP patients, PPI was impaired while R 1 facilitation was absent. PPI size did not correlate with the motor symptom severity and disease duration. Patients with sensory tricks showed better PPI than those without sensory tricks.
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Affiliation(s)
- Xinqing Hao
- Department of Neurology, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Xiaofeng Huang
- Department of Neurology, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Xiaoxue Yin
- Department of Neurology, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Hai-Yang Wang
- Department of Neurology, The First Affiliated Hospital of Dalian Medical University, Dalian, China,Department of Neurology, Jining No. 1 People's Hospital, Jining, China
| | - Ren Lu
- Department of Neurology, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Zhanhua Liang
- Department of Neurology, The First Affiliated Hospital of Dalian Medical University, Dalian, China,*Correspondence: Zhanhua Liang ✉
| | - Chunli Song
- Department of Neurology, The First Affiliated Hospital of Dalian Medical University, Dalian, China,Chunli Song ✉
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Functional neurological disorder: new subtypes and shared mechanisms. Lancet Neurol 2022; 21:537-550. [PMID: 35430029 PMCID: PMC9107510 DOI: 10.1016/s1474-4422(21)00422-1] [Citation(s) in RCA: 118] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 10/14/2021] [Accepted: 11/24/2021] [Indexed: 01/12/2023]
Abstract
Functional neurological disorder is common in neurological practice. A new approach to the positive diagnosis of this disorder focuses on recognisable patterns of genuinely experienced symptoms and signs that show variability within the same task and between different tasks over time. Psychological stressors are common risk factors for functional neurological disorder, but are often absent. Four entities-functional seizures, functional movement disorders, persistent perceptual postural dizziness, and functional cognitive disorder-show similarities in aetiology and pathophysiology and are variants of a disorder at the interface between neurology and psychiatry. All four entities have distinctive features and can be diagnosed with the support of clinical neurophysiological studies and other biomarkers. The pathophysiology of functional neurological disorder includes overactivity of the limbic system, the development of an internal symptom model as part of a predictive coding framework, and dysfunction of brain networks that gives movement the sense of voluntariness. Evidence supports tailored multidisciplinary treatment that can involve physical and psychological therapy approaches.
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Insola A, Mazzone P, Della Marca G, Capozzo A, Vitale F, Scarnati E. Pedunculopontine tegmental Nucleus-evoked prepulse inhibition of the blink reflex in Parkinson's disease. Clin Neurophysiol 2021; 132:2729-2738. [PMID: 34417108 DOI: 10.1016/j.clinph.2021.06.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To investigate the effects on the blink reflex (BR) of single stimuli applied to the pedunculopontine tegmental nucleus (PPTg). METHODS The BR was evoked by stimulating the supraorbital nerve (SON) in fifteen patients suffering from idiopathic Parkinson's disease (PD) who had electrodes monolaterally or bilaterally implanted in the PPTg for deep brain stimulation (DBS). Single stimuli were delivered to the PPTg through externalized electrode connection wires 3-4 days following PPTg implantation. RESULTS PPTg stimuli increased the latency and reduced duration, amplitude and area of the R2 component of the BR in comparison to the response recorded in the absence of PPTg stimulation. These effects were independent of the side of SON stimulation and were stable for interstimulus interval (ISI) between PPTg prepulse and SON stimulus from 0 to 110 ms. The PPTg-induced prepulse inhibition of the BR was bilaterally present in the brainstem. The R1 component was unaffected. CONCLUSIONS The prepulse inhibition of the R2 component may be modulated by the PPTg. SIGNIFICANCE These findings suggest that abnormalities of BR occurring in PD may be ascribed to a reduction of basal ganglia-mediated inhibition of brainstem excitability.
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Affiliation(s)
- Angelo Insola
- Clinical Neurophysiopathology, CTO Andrea Alesini Hospital, ASL Roma 2, Via San Nemesio 21, 00145 Rome, Italy.
| | - Paolo Mazzone
- Functional and Stereotactic Neurosurgery, CTO Andrea Alesini Hospital, ASL Roma 2, Via San Nemesio 21, 00145 Rome, Italy
| | - Giacomo Della Marca
- Institute of Neurology, Catholic University, Largo A.Gemelli 8, 00168 Rome, Italy
| | - Annamaria Capozzo
- Department of Biotechnological and Applied Clinical Sciences (DISCAB), University of L'Aquila, Via Vetoio Coppito 2, 67100 L'Aquila, Italy
| | - Flora Vitale
- Department of Biotechnological and Applied Clinical Sciences (DISCAB), University of L'Aquila, Via Vetoio Coppito 2, 67100 L'Aquila, Italy
| | - Eugenio Scarnati
- Department of Biotechnological and Applied Clinical Sciences (DISCAB), University of L'Aquila, Via Vetoio Coppito 2, 67100 L'Aquila, Italy
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Dreissen YEM, Koelman JHTM, Tijssen MAJ. The auditory startle response in relation to outcome in functional movement disorders. Parkinsonism Relat Disord 2021; 89:113-117. [PMID: 34274620 DOI: 10.1016/j.parkreldis.2021.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 07/07/2021] [Accepted: 07/12/2021] [Indexed: 11/18/2022]
Abstract
BACKGROUND The auditory startle reflex (ASR) is enlarged in patients with functional movement disorders (FMD). OBJECTIVES To study whether the ASR relates to symptom reduction in FMD patients, who participated in a placebo controlled double blind treatment trial with Botulinum Neurotoxin (BoNT). METHODS Response to treatment in the BoNT study was assessed using the Clinical Global Impression - Improvement scale (CGI-I). The electromyography (EMG) muscle activity of 7 muscles following 110 dB tones was measured in 14 FMD patients before and after one-year treatment and compared to 11 matched controls. The early and a late (behaviorally affected) component of the ASR and the sympathetic skin response (SSR) were assessed. RESULTS 10 of 14 patients (71.4%) showed symptom improvement, which was believed to be mainly caused by placebo effects. The early total response probability of the ASR at baseline tended to be larger in patients compared to controls (p = 0.08), but normalized at follow-up (p = 0.84). The late total response probability was larger in patients vs. controls at baseline (p < 0.05), a trend that still was present at follow-up (p = 0.08). The SSR was higher in patients vs. controls at baseline (p < 0.01), and normalized at follow-up (p = 0.71). CONCLUSIONS On a group level 71.4% of the patients showed clinical symptom improvement after treatment. The early part of the ASR, most likely reflecting anxiety and hyperarousal, normalized in line with the clinical improvement. Interestingly, the augmented late component of the ASR remained enlarged suggesting persistent altered behavioral processing in functional patients despite motor improvement.
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Affiliation(s)
- Y E M Dreissen
- Department of Neurology and Clinical Neurophysiology, Amsterdam University Medical Center, University of Amsterdam, the Netherlands
| | - J H T M Koelman
- Department of Neurology and Clinical Neurophysiology, Amsterdam University Medical Center, University of Amsterdam, the Netherlands
| | - M A J Tijssen
- Department of Neurology, University Medical Centre Groningen, University Groningen, the Netherlands.
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