{"id":256530,"date":"2026-07-13T14:51:56","date_gmt":"2026-07-13T11:51:56","guid":{"rendered":"https:\/\/1kitap1.com\/en\/clinical-neurophysiology-dr-daniela-p-quayle-1\/"},"modified":"2026-07-13T14:51:56","modified_gmt":"2026-07-13T11:51:56","slug":"clinical-neurophysiology-dr-daniela-p-quayle-1","status":"publish","type":"post","link":"https:\/\/1kitap1.com\/en\/clinical-neurophysiology-dr-daniela-p-quayle-1\/","title":{"rendered":"Clinical Neurophysiology – Dr Daniela P Quayle (1)"},"content":{"rendered":"
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Asymmetry is seen in focal brainstem or nerve lesions. Blink reflex recovery The blink reflex is a brainstem-mediated reflex covered in the \u2018Cranial nerve studies\u2019 section of this chapter. The blink reflex recovery uses the R2 recovery after repeated stimulation as a measure of brainstem inhibitory function, specifically the trigeminal-facial brainstem circuit: An increased blink reflex recovery shows faster R2 recovery and suggests reduced brainstem inhibition.<\/p>\n

Faster R2 recovery time can be reduced in brainstem GABAergic inhibition, hyperactive thalamic drive and dopaminergic dysregulation in the striatum. R2 recovery time can be prolonged in overactive cortico-striato-thalamo-cortical (CSTC) loop. R2 amplitude can be impacted by impaired motor control and sensorimotor integration, dysregulated cortical excitability, basal ganglia dysfunction and serotonergic dysfunction.<\/p>\n

R2 latency can be delayed in delayed inhibition from prefrontal circuits, reduced brainstem processing speed, dysfunctional interneuron networks, and abnormal myelination or white matter changes. There is faster R2 recovery (reduced inhibition) in: Movement disorders (e.g. dystonia, Parkinson\u2019s disease, essential tremor, Tourette\u2019s syndrome) due to brainstem disinhibition and loss of GABAergic control.<\/p>\n

Some psychiatric disorders. In schizophrenia, faster R2 recovery is thought to be due to brainstem disinhibition and reduced GABAergic control. In post-traumatic stress disorder (PTSD), faster R2 recovery is thought to be due to hyperactive amygdala-brainstem circuits. Some pain disorders. In trigeminal neuralgia, faster R2 recovery is also associated with increased R2 amplitudes and shortened\/prolonged\/asymmetric R2 latency due to trigeminal hyperexcitability and loss of brainstem inhibition.<\/p>\n

In cluster headaches, faster R2 recovery is also associated with increased amplitude due to brainstem hyperexcitability and trigeminal autonomic dysfunction. In migraine with brainstem aura (i.e. associated with vertigo, ataxia, dysarthria, diplopia and tinnitus rather than visual perception, sensory disturbance and aphasia, which are thought to be due to cortical spreading depression at cerebral cortex), there is faster R2 recovery due to hyperactive brainstem pain circuits and impaired cortical- brainstem inhibition.<\/p>\n

There is delayed or absent R2 recovery in neurodegenerative disease (e.g. progressive supranuclear palsy, MSA, ALS) due to brainstem degeneration and corticobulbar dysfunction. The R2 response may be absent or asymmetric in brainstem lesions, especially those affecting the trigeminofacial pathway (e.g. pontine infarcts, MS and brainstem tumours). The R2 response may also be prolonged or absent in peripheral nerve disorders (e.g.<\/p>\n

Bell\u2019s palsy, GBS, chronic inflammatory demyelinating polyneuropathy) due to facial or trigeminal nerve dysfunction. \u2022 \u2022 \u2022 \u2022 \u2022 \u2022 \u2022 \u2022 \u2022 \u2022 \u2022 R2 responses are variable in obsessive-compulsive disorder (e.g. R2 recovery time can be prolonged or normal due to overactive cortico-striato-thalamo-cortical loop, R2 amplitude can be more variable and R2 latency can be prolonged). There is reduced R2 habituation in autism spectrum disorder (ASD) due to impaired sensorimotor gating and hyperactivity to sensory input. Startle reflex The startle reflex is a brainstem-mediated reflex in response to an intense, sudden stimulus.<\/p>\n

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Oxford Specialist Handbooks published and forthcoming General Oxford Specialist Handbooks A Resuscitation Room Guide Addiction Medicine Day Case Surgery Infection in the Immunocompromised Host Parkinson\u2019s Disease and Other Movement Disorders, 2e Perioperative Medicine, 2e Pharmaceutical Medicine Postoperative Complications, 2e Prison Medicine and Health Renal Transplantation Retrieval Medicine Oxford Specialist Handbooks in Anaesthesia Anaesthesia for Medical and Surgical Emergencies Cardiac Anaesthesia Neuroanaesthesia Global Anaesthesia Obstetric Anaesthesia Ophthalmic Anaesthesia Paediatric Anaesthesia Regional Anaesthesia, Stimulation and Ultrasound Techniques Thoracic Anaesthesia Oxford Specialist Handbooks in Cardiology Adult Congenital Heart Disease Cardiac Catheterization and Coronary Intervention Cardiac Electrophysiology and Catheter Ablation Cardiovascular Computed Tomography Cardiovascular Magnetic Resonance Echocardiography, 2e Fetal Cardiology Heart Failure, 3e Hypertension Inherited Cardiac Disease Nuclear Cardiology Pacemakers and ICDs Paediatric Cardiology Pulmonary Hypertension Valvular Heart Disease Oxford Specialist Handbooks in Critical Care Advanced Respiratory Critical Care Cardiothoracic Critical Care Oxford Specialist Handbooks in End of Life Care End of Life Care in Cardiology End of Life Care in Dementia End of Life Care in Nephrology End of Life Care in Respiratory Disease End of Life in the Intensive Care Unit Oxford Specialist Handbooks in Infectious Disease Infectious Disease Epidemiology Manual of Childhood Infections, 4e Oxford Specialist Handbooks in Neurology Epilepsy Parkinson\u2019s Disease and Other Movement Disorders, 2e Stroke Medicine, 2e Oxford Specialist Handbooks in Oncology Myeloproliferative Neoplasms Practical Management of Complex Cancer Pain Radiotherapy Planning Oxford Specialist Handbooks in Paediatrics Paediatric Dermatology Paediatric Endocrinology and Diabetes Paediatric Gastroenterology, Hepatology, and Nutrition Paediatric Haematology and Oncology Paediatric Intensive Care Paediatric Nephrology, 2e Paediatric Neurology, 4e Paediatric Palliative Medicine, 2e Paediatric Radiology Paediatric Respiratory Medicine Paediatric Rheumatology Oxford Specialist Handbooks in Pain Medicine Spinal Interventions in Pain Management Oxford Specialist Handbooks in Psychiatry Addiction Medicine, 3e Child and Adolescent Psychiatry Eating Disorders Forensic Psychiatry Medical Psychotherapy Old Age Psychiatry Oxford Specialist Handbooks in Radiology Head and Neck Imaging Interventional Radiology Musculoskeletal Imaging Pulmonary Imaging Thoracic Imaging Oxford Specialist Handbooks in Surgery Burns Cardiothoracic Surgery, 2e Colorectal Surgery Gastric and Oesophageal Surgery Hand Surgery Hand Surgery Hepatopancreatobiliary Surgery Neurosurgery Operative Surgery, 2e Oral and Maxillofacial Surgery, 2e Otolaryngology and Head and Neck Surgery Paediatric Surgery Plastic and Reconstructive Surgery Surgical Oncology Urological Surgery 2e Vascular Surgery 2e 1kitap1.com\/en Clinical Neurophysiology Daniela P. Quayle Honorary Research Fellow, Imperial College London Consultant in Clinical Neurophysiology, Charing Cross Hospital, Imperial College Healthcare NHS Trust, Fulham Palace Road, London 1kitap1.com\/en Great Clarendon Street, Oxford, OX2 6DP, United Kingdom Oxford University Press is a department of the University of Oxford.<\/p>\n<\/blockquote>\n

This is a short excerpt from the opening of “” by Unknown, quoted for review and introduction purposes. All rights belong to the copyright holders.<\/em><\/p>\n

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