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Mark VW. Biomarkers and Rehabilitation for Functional Neurological Disorder. J Pers Med 2024; 14:948. [PMID: 39338202 PMCID: PMC11433361 DOI: 10.3390/jpm14090948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2024] [Revised: 08/21/2024] [Accepted: 09/02/2024] [Indexed: 09/30/2024] Open
Abstract
Functional neurological disorder, or FND, is widely misunderstood, particularly when considering recent research indicating that the illness has numerous biological markers in addition to its psychiatric disorder associations. Nonetheless, the long-held view that FND is a mental illness without a biological basis, or even a contrived (malingered) illness, remains pervasive both in current medical care and general society. This is because FND involves intermittent disability that rapidly and involuntarily alternates with improved neurological control. This has in turn caused shaming, perceived low self-efficacy, and social isolation for the patients. Until now, biomarker reviews for FND tended not to examine the features that are shared with canonical neurological disorders. This review, in contrast, examines current research on FND biomarkers, and in particular their overlap with canonical neurological disorders, along with the encouraging outcomes for numerous physical rehabilitation trials for FND. These findings support the perspective endorsed here that FND is unquestionably a neurological disorder that is also associated with many biological markers that lie outside of the central nervous system. These results suggest that FND entails multiple biological abnormalities that are widely distributed in the body. General healthcare providers would benefit their care for their patients through their improved understanding of the illness and recourses for support and treatment that are provided in this review.
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Affiliation(s)
- Victor W. Mark
- Department of Physical Medicine and Rehabilitation, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA; ; Tel.: +1-205-934-3499
- Department of Neurology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35249, USA
- Department of Psychology, College of Arts and Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Wang S, Xiong Z, Cui Y, Fan F, Zhang S, Jia R, Hu Y, Li L, Zhang X, Han F. Placebo and Nocebo Responses in Pharmacological Trials of Tic Disorders: A Meta-Analysis. Mov Disord 2024; 39:585-595. [PMID: 38247265 DOI: 10.1002/mds.29714] [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: 09/30/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 01/23/2024] Open
Abstract
BACKGROUND Clinical trials of new drugs for tic disorders (TD) often fail to yield positive results. Placebo and nocebo responses play a vital role in interpreting the outcomes of randomized controlled trials (RCTs), yet these responses in RCTs of TD remain unexplored. OBJECTIVE The aim was to assess the magnitude of placebo and nocebo responses in RCTs of pharmacological interventions for TD and identify influencing factors. METHODS A systematic search of the Embase, Medline, Cochrane Central Register of Controlled Trials, and PsycINFO databases was conducted. Eligible studies were RCTs that compared active pharmacological agents with placebos. Placebo response was defined as the change from baseline in TD symptom severity in the placebo group, and nocebo response as the proportion experiencing adverse events (AEs) in this group. Subgroup analysis and meta-regression were performed to explore modifying factors. RESULTS Twenty-four trials involving 2222 participants were included in this study. A substantial placebo response in TD symptom severity was identified, with a pooled effect size of -0.79 (95% confidence interval [CI] -0.99 to -0.59; I2 = 67%). Forty-four percent (95% CI 27% to 63%; I2 = 92%) of patients experienced AEs while taking inert pills. Sample size, study design, and randomization ratio were correlated with changes in placebo and nocebo responses. CONCLUSION There were considerable placebo and nocebo responses in TD clinical trials. These results are of great relevance for the design of future trials and for clinical practice in TD. SYSTEMATIC REVIEW REGISTRATION PROSPERO registration ID CRD42023388397. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Simeng Wang
- Department of Pediatrics, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Zhiyi Xiong
- School of Acupuncture-Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing, China
| | - Yuehua Cui
- Department of Pediatrics, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Fei Fan
- Department of Pediatrics, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Si Zhang
- Department of Pediatrics, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Ru Jia
- Department of Pediatrics, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yuchen Hu
- Department of Pediatrics, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Liang Li
- Department of Traditional Chinese Medicine, Children's Hospital of Soochow University, Soochow, China
| | - Xuan Zhang
- Chinese EQUATOR Center, Hong Kong Chinese Medicine Clinical Study Center, Chinese Clinical Trial Registry (Hong Kong), School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Fei Han
- Department of Pediatrics, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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Lv Y, Wang M, Yang J, Shi J, Xuan T, Zhang J, Du D, Cheng J, Li H. Cerebellar repetitive transcranial magnetic stimulation versus propranolol for essential tremor. Brain Behav 2023; 13:e2926. [PMID: 36806734 PMCID: PMC10013940 DOI: 10.1002/brb3.2926] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 02/05/2023] [Accepted: 02/05/2023] [Indexed: 02/20/2023] Open
Abstract
BACKGROUND Propranolol, a nonselective beta-adrenergic blocker, has long been used as one of the standard treatments for essential tremor (ET). Repetitive transcranial magnetic stimulation (rTMS) has also been used for a long time as a substitution therapy for ET patients. OBJECTIVE The main aim of this study was to evaluate the antitremor effect of 1-Hz (low-frequency) cerebellar rTMS and compare it to the use of propranolol in ET patients. METHODS In this single-blinded, randomized, controlled pilot study, a total of 38 patients with ET were randomized into two groups. One group (n = 20) received 1200 pulses of 1-Hz rTMS at an intensity of 90% of the resting motor threshold to the bilateral cerebellar region for 10 days. Another group (n = 18) received oral propranolol for 30 days. The initial dose was 30 mg/day, which was increased to 60 mg/day after 5 days, then to 90 mg/day on the 11th day, and continued thereafter for 20 days. The Fahn-Tolosa-Marin (FTM) clinical scale was assessed at baseline and at days 5, 10, and 30 to evaluate tremor severity, specific motor tasks, and functional disability. RESULTS Low-frequency rTMS of the cerebellum significantly improved tremor severity, specific motor tasks (writing, spiral drawing, and pouring), and FTM total scores on days 10 and 30. Nevertheless, we found no significant difference in functional disability at any point in time (p > .05). There were no statistically significant differences in FTM Part A, Part B, Part C scores and total scores of patients in propranolol group on days 5 and 10 compared with before treatment (p > .05). However, FTM total scores and FTM Part A, Part B, and Part C scores were significantly improved for patients when the dose of propranolol was 90 mg/day on day 30. Our study showed that there was no statistically significant difference in the total FTM scores and FTM Part A, Part B, and Part C scores between rTMS and propranolol on days 5, 10, and 30 (p > .05). CONCLUSION We conclude that both cerebellar low-frequency rTMS and propranolol could be effective treatment options for patients with ET, but it is not clear which method is more effective.
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Affiliation(s)
- Yue Lv
- Department of Neurology, General Hospital of Ningxia Medical University, Yinchuan, China.,School of Clinical Medicine, Ningxia Medical University, Yinchuan, China
| | - Mengran Wang
- Department of Neurology, General Hospital of Ningxia Medical University, Yinchuan, China.,School of Clinical Medicine, Ningxia Medical University, Yinchuan, China
| | - Juan Yang
- Department of Neurology, General Hospital of Ningxia Medical University, Yinchuan, China.,Diagnosis and Treatment Engineering Technology Research Center of Nervous System Diseases of Ningxia Hui Autonomous Region, Yinchuan, China
| | - Jin Shi
- Department of Neurology, General Hospital of Ningxia Medical University, Yinchuan, China.,School of Clinical Medicine, Ningxia Medical University, Yinchuan, China
| | - Tingting Xuan
- Department of Neurology, General Hospital of Ningxia Medical University, Yinchuan, China.,School of Clinical Medicine, Ningxia Medical University, Yinchuan, China
| | - Junmei Zhang
- Department of Neurology, General Hospital of Ningxia Medical University, Yinchuan, China.,School of Clinical Medicine, Ningxia Medical University, Yinchuan, China
| | - Dandan Du
- Department of Neurology, General Hospital of Ningxia Medical University, Yinchuan, China.,School of Clinical Medicine, Ningxia Medical University, Yinchuan, China
| | - Jiang Cheng
- Department of Neurology, General Hospital of Ningxia Medical University, Yinchuan, China.,Diagnosis and Treatment Engineering Technology Research Center of Nervous System Diseases of Ningxia Hui Autonomous Region, Yinchuan, China
| | - Haining Li
- Department of Neurology, General Hospital of Ningxia Medical University, Yinchuan, China.,Diagnosis and Treatment Engineering Technology Research Center of Nervous System Diseases of Ningxia Hui Autonomous Region, Yinchuan, China
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Maas RPPWM, van de Warrenburg BPC. Therapeutic Misestimation in Patients with Degenerative Ataxia: Lessons from a Randomized Controlled Trial. Mov Disord 2023; 38:133-137. [PMID: 36259428 PMCID: PMC10092424 DOI: 10.1002/mds.29252] [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: 05/05/2022] [Revised: 09/06/2022] [Accepted: 09/29/2022] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND The absence of effective treatments may render patients with degenerative cerebellar ataxias susceptible to a placebo response, which could affect the outcome of clinical trials. OBJECTIVE To retrospectively examine expectations of benefit in participants of an ataxia trial and identify determinants of possible therapeutic misestimation. METHODS Individuals with spinocerebellar ataxia type 3 who participated in a randomized, double-blind, sham-controlled trial received a custom-designed questionnaire about short-term and long-term treatment expectations, allocation preferences, and interpretation of treatment arm assignment based on the presence or absence of clinical improvement. To evaluate whether expectations were specifically related to the application of cerebellar transcranial direct current stimulation (tDCS) or more generally reflect an overly positive attitude of patients with ataxia toward trial participation and results, the last questions involved a hypothetical scenario in which an oral drug was tested against placebo with an aim identical to that of our tDCS study. RESULTS All 20 trial participants completed the questionnaire. If allocated to the active treatment arm, 75% of patients expected short-term health benefits and 55% thought they would still have less severe ataxia at 1-year follow-up compared with baseline. After 2 weeks, an average reduction in ataxia severity of 31.5% (standard deviation, 22.2%) was anticipated. Conversely, 65% associated a lack of improvement with probable or definite allocation to the placebo group. High expectations of benefit were neither related to the type of intervention nor to clinical or demographic characteristics. CONCLUSION Therapeutic misestimation is common in patients with degenerative ataxia and requires special attention in future trials. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Roderick P P W M Maas
- Department of Neurology, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Bart P C van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
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Cavanna AE. Current and emerging pharmacotherapeutic strategies for Tourette syndrome. Expert Opin Pharmacother 2022; 23:1523-1533. [PMID: 35913140 DOI: 10.1080/14656566.2022.2107902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Tourette syndrome (TS) is a chronic tic disorder characterized by both motor and vocal tics. The vast majority of patients present with co-morbid behavioral problems, especially tic-related obsessive-compulsive behaviors and attention-deficit and hyperactivity disorder. Evidence-based guidelines on the pharmacotherapy of TS have become available in recent years. AREAS COVERED The main purpose of this paper is to provide an overview of the current and emerging pharmacotherapeutic strategies for TS. A comprehensive search for the literature on the pharmacotherapy of tics was conducted using multiple databases (MEDLINE, Scopus, Web of Science, and Google Scholar), without date limits. EXPERT OPINION In consideration of the heterogeneity of the TS phenotypes, pharmacotherapy should be tailored to the individual patient. The choice of the pharmacological agent should take into account both the efficacy-to-tolerability ratio and the presence of co-morbid conditions. Evidence-based pharmacotherapy should aim at improving health-related quality life within a dynamic framework that typically requires active monitoring of the clinical presentation and reevaluation of the treatment intervention over time.
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Affiliation(s)
- Andrea E Cavanna
- Department of Neuropsychiatry, BSMHFT and University of Birmingham, Birmingham, UK.,School of Life and Health Sciences, Aston University, Birmingham, UK.,University College London and Institute of Neurology, London, UK
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Wang ZX, Zhang NN, Zhao HX, Song J. Nocebo effect in multiple system atrophy: systematic review and meta-analysis of placebo-controlled clinical trials. Neurol Sci 2022; 43:899-905. [PMID: 34973075 PMCID: PMC8789733 DOI: 10.1007/s10072-021-05758-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 11/15/2021] [Indexed: 11/28/2022]
Abstract
Background Nocebo effect is prevalent among neurological diseases, resulting in low adherence and treatment outcome. We sought to examine the nocebo effect in randomized controlled trials (RCTs) in multiple system atrophy (MSA). Methods We searched RCTs in MSA from Medline since September, 2021. RCTs for drug treatment conducted in adult MSA patients with more than 5 cases in each treatment arm were included. We assessed the number of dropout due to placebo intolerance. We also did a symptomatic/disease-modifying subgroup analysis based on two different treatment purposes. The STATA software was used for statistical analysis. Overall heterogeneity was assessed using the Cochran Q and I2. Results Data were extracted from 11 RCTs fulfilling our search criteria. Of 540 placebo-treated patients, 64.2% reported at least one adverse event (AE) and 7.5% reported dropout because of AEs. The chance of dropping out because of an AE and experiencing at least one AE did not differ between placebo and active drug treatment arms. Besides, the pooled nocebo dropout rate in the symptomatic subgroup was similar to that of the disease-modifying subgroup. Conclusion In MSA RCTs, nocebo dropout rate was not at a low level among neurological disorders. Nocebo effect was an important reason of dropout because of AE in placebo and active drug treatment arms. Different treatment purposes may not influence nocebo effect.
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Affiliation(s)
- Zi-Xuan Wang
- Department of Geriatrics, the Affiliated Hospital of Qingdao University, Qingdao, 266071, China.
- Institute of Neuroregeneration and Neurorehabilition, Qingdao University, Qingdao, 266071, China.
| | - Nan-Nan Zhang
- Department of Geriatrics, the Affiliated Hospital of Qingdao University, Qingdao, 266071, China
| | - Hai-Xia Zhao
- Department of Neurology, the Third People's Hospital of Qingdao, Qingdao University, Qingdao, 266000, China
| | - Jie Song
- Department of Geriatrics, the Affiliated Hospital of Qingdao University, Qingdao, 266071, China
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Rodrigues FB, Ferreira JJ. Strategies to minimize placebo effects in research investigations. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2020; 153:49-70. [PMID: 32563293 DOI: 10.1016/bs.irn.2020.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Placebo-controlled trials are the research standard to evaluate new interventions for which there is no standard of care. While lessening performance and detection bias, such design provides a direct mode of comparison against the probed intervention. Still, using placebo arms may pose new challenges to the design, conduct and analysis of clinical trials. This is particularly relevant in circumstances of non-additivity between the therapeutic and the placebo effects, if the outcome of interest has floor or ceiling effects, or when the predicted effect size of the intervention is large and leads to small sample sizes. There are several possible strategies to mitigate the confounding effects of the placebo, each relevant to specific clinical trial designs. This chapter puts into context the new challenges created by the placebo effect, discusses possible ways around them, and explores the future of the field.
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Affiliation(s)
- Filipe B Rodrigues
- UCL Huntington's Disease Centre, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom; Laboratory of Clinical Pharmacology and Therapeutics, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal; Instituto de Medicina Molecular, Lisbon, Portugal
| | - Joaquim J Ferreira
- Laboratory of Clinical Pharmacology and Therapeutics, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal; Instituto de Medicina Molecular, Lisbon, Portugal; CNS-Campus Neurológico Sénior, Torres Vedras, Portugal.
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Maximizing placebo response in neurological clinical practice. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2020; 153:71-101. [PMID: 32563294 DOI: 10.1016/bs.irn.2020.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The placebo effect is a widely recognized phenomenon in clinical research, with a negative perception that it could hide the "true" drug effect. In clinical care its positive potential to increase known drug effects has been neglected for too long. The placebo and nocebo responses have been described in many neurologic disorders such as Parkinson's, Huntington's and Alzheimer's diseases, restless leg syndrome, tics, essential tremor, dystonia, functional movement disorders, neuropathic pain, headaches, migraine, amyotrophic lateral sclerosis, myasthenia gravis, chronic inflammatory demyelinating polyneuropathy, multiple sclerosis and epilepsy. Knowledge regarding placebo mechanisms and their consequences on clinical outcome have greatly improved over the last two decades. This evolution has led to reconsiderations of the importance of placebo response in the clinic and has given several clues on how to improve it in daily practice. In this chapter, we first illustrate "why," e.g. the reasons (relevance to clinical practice, help in differential diagnosis/treatment of psychogenic movements, clinical impact, proven neurobiological grounds, health economic potential), and "how," e.g. the means (increase patients' knowledge, increase learning, improve patient-doctor relationship, increase Hawthorne effect, increase positive/decrease negative expectations (the Rosenthal effect), personalize placebo response), the placebo should be maximized (and nocebo avoided) in neurological clinical practice. Future studies regarding more specific neurobiological mechanisms will allow a finer tuning of placebo response in clinical practice. The use of placebo in clinical practice raises ethical issues, and a recent expert consensus regarding placebo use in the clinic is a first step to future guidelines necessary to this field.
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