Neurophysiology

Sir Ganga Ram Hospital

Ganga Ram Institute For Post Graduate Medical Education & Research (Gripmer)

Neurophysiology Contact Number:  +91 11 42251714   +91 11 42251718.

Consultants:

Dr M Gourie-devi: Advisor and Senior Consultant Neurologist

Dr Laxmi Khanna: Chairperson and Senior Consultant Neurologist

Dr Ankkita Sharma Bhandari: Consultant Neurophysiologist

Front row sitting left to right: Dr. Ankkita Sharma Bhandari (Consultant), Dr. M. Gourie-Devi (Advisor & Senior consultant),

Dr Laxmi Khanna (Chairperson & Senior consultant) Middle row standing from left to right: Ms Arshiya Fatima, Ms Anjana Thakur, Ms Dhanwanti, Ms Dimple Kapur Back row standing from left to right: Mr Vijay Sharma, Mr Govind Singh Bisht, Mr Amit Rana, Mr Satish Gupta, Mr Sonu

A. About the department

Neurophysiological diagnostic tests are considered as an extension of Clinical neurology assessment since valuable data emanating is crucial for the diagnosis of a number of neurological disorders: epilepsy, encephalopathy, multiple sclerosis, cerebrovascular disorder, brain tumours, infections of nervous system, developmental disorders, optic neuritis, auditory dysfunction, traumatic injuries of brain, spinal cord, roots, plexus and nerves, cervical and lumbar spondylosis, motor neuron disease, peripheral neuropathy, carpal tunnel syndrome, neuromuscular junction disorders, muscle disorders etc. The diagnostic tests were first established at Sir Ganga Ram hospital in 1984 and during the next three decades, in keeping with the global developments, the department has acquired state of art equipments and has brought improvement in techniques to enhance the diagnostic accuracy.

B. Consultants

Prof Dr. M.Gourie-Devi. DM (Neuro); DSc (Hon); FAMS; FAAS; FIAN; FNAS Advisor of Department of Neurophysiology. She is a Senior consultant in Neurology & Neurophysiology. She had been the Chairperson of Department of Neurophysiology from 2003. During these two decades notable developments had occurred in establishing state-of-art laboratories in keeping with advances in technology. Internationally accepted protocols for diagnosis have been put in practice. Teaching and training programs for postgraduate students in Neurology, visiting fellows from India and abroad and technicians have been developed. She is currently Honorary Advisor for Neurological Research, Indian Council of Medical Research, Emeritus Professor of Neurology, Institute of Human Behaviour &Allied Sciences and Expert Member of Advisory Panel of World Health Organization on Neurosciences. Dr.Gourie-Devi has made notable contributions in the fields of Motor neuron disease, credited with description of Monomelic Amyotrophy, genetics of amyotrophic lateral sclerosis, hyaluronidase in management of spinal arachnoiditis in Neurotuberculosis, Japanese encephalitis, Peripheral neuropathy in Leprosy and Clinical Neurophysiology. She is former Director-Vice Chancellor and Professor of Neurology at National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore. She has been a recipient of numerous awards, notable are Dr.B.C.Roy Award in the Category of ‘Eminent Medical Person’, Medical Council of India, D.Sc (Honoris Causa) by NTR University of Health Sciences, Basanti Devi Amir Chand Prize – Indian Council of Medical Research and Kugelberg Award by International Federation of Clinical Neurophysiology. Areas of interest: Motor neuron disease, Monomelic Amyotrophy, peripheral neuropathy, muscle disorders.

Dr Laxmi Khanna is Senior Consultant and Chairperson in Department of Neurophysiology. She completed her Post graduation in Neurology from Sir Ganga Ram Hospital in 2011 and has been working as consultant in Neurology since then. She has vast experience in Neurophysiology and interpretation of EEGs. She has undergone EEG Epilepsy intensive course from University Hospitals Cleveland Medical Center, USA in 2019 and undergone training in Pediatric EEG and Advanced EEG through the ILAE Academy. She has completed the IES Video EEG Course in 2021. She has also completed a sleep training programme from Sleep school Atlanta, USA. and has qualified as an International Sleep Disorders Specialist. She has undergone further training at the Sleep Medicine Institute at the Neurology& Sleep Centre, New Delhi and completed the Comprehensive Sleep Medicine Course by the Indian Sleep Disorders Association conducted at New Delhi in 2021. She has attended and presented a Poster at the AAN 2022 Summer Conference at San Francisco, USA in July 2022. She has trained in the administration of Botulinum Toxin for Spasticity and Movement disorders. She has 33 publications to her credit. She has a keen interest in training undergraduates and post graduates in Neurophysiology. She is a member of the American Association of Neurologists, Indian Academy of Neurologists, Indian Epilepsy society, Indian Society for Sleep Research, Indian Sleep Disorders Association and Delhi Neurological Association. She has completed the Specialist Certification in Neurology in 2018 and has received the Fellowship of the Royal College of Physicians in 2021. Area of interest – Neurology, Sleep Medicine & Epilepsy & Neurophysiology.

Dr Ankkita Sharma Bhandari is Consultant in Department of Clinical Neurophysiology at Sir Ganga Ram Hospital, New Delhi, India. She holds MD degree in Physiology from Government medical college, Jammu, India 2013. She has undergone specialised training in clinical neurophysiology at Sir Ganga Ram Hospital, New Delhi, India (2013-2016); Intensive EEG Epilepsy course at University hospital, Cleveland Medical Center, Neurological Institute, USA 2018; Virtual fall course from American clinical neurophysiology society, 2020; IES Video EEG Course by Indian epilepsy society (IES) Epilepsy surgery subsection, 2021; Basic course in sleep medicine from Neurology and sleep centre, New delhi, India 2020: Fellowship curriculum-EEG from American epilepsy society, 2022. She is also working as Surgical neurophysiologist in Orthospine and Neurosurgery procedures. She is Life associate member of Indian academy of neurology and Life member of Indian society for sleep research. She has also been part of various research works related to amyotrophic lateral sclerosis, epilepsy and neuromuscular disorders. Various studies related to field of Clinical neurophysiology and physiology have been published/presented by her in national/international journals and conferences. Areas of interest: Neurophysiological assessment of neuromuscular disorders, epilepsy, motor neuron disease, and peripheral neuropathy; Sleep; Intraoperative neuromonitoring; General Physiology.

ing programme for residents in neurology, visiting fellows and technicians has added vibrancy to the department.

C. Teaching and training programmes The technical staff strength comprises six technicians presently. The department has one Senior Resident and DNB students from the department of Neurology are also posted as per their academic roster. An active teaching and training programme for residents in neurology, visiting fellows and technicians has added vibrancy to the department.

i) Post graduate students of DNB in Neurology are posted to the department of Neurophysiology for two to three months on rotation, during which they receive intensive training in performance and interpretation of the diagnostic tests and their neurophysiologic basis.

ii) Faculty/ consultants in medicine, paediatrics and physiology from different regions of the country and abroad pursue advanced training in the department on fellowship programme for few months.

iii) The Department of Neurophysiology initiated training programme in 1996 creating technical manpower. Every year, two trainees with science background are recruited for intensive training in all the neurophysiology diagnostic procedures through a ‘hands-on’ program strengthened by lectures by faculty and senior technicians of the department. During the course of 2 years the trainees are familiarized with the equipment, operation of the machines and learn to recognize and rectify commonly encountered artefacts. Preparation of the patient for the procedure, placement of electrodes, stimulation techniques and recording of the results are the essential components of the training programme. The candidates after successful completion of the course are employed as technicians in different hospitals and institutions in the country. At present, we are also training candidates who have completed BSc in Neurophysiology from recognised Universities in and around New Delhi.

D. Services

The Department of Neurophysiology offers diagnostic services for the comprehensive evaluation of diseases of central nervous system and peripheral nervous system.

The diagnostic tests carried out are listed below:

• Electroencephalography (EEG)
• Short Term Video EEG monitoring (STVEEG)
• Long Term Video EEG monitoring (LTVEEG)
• Portable EEG Monitoring
• Nerve Conduction Studies (NCS) (Sensory, motor, autonomic, blink reflex)
• Electromyography (EMG)
• Repetitive Nerve Stimulation (RNST)
• Portable NCS, EMG, RNST
• Evoked potential

1.Visual Evoked Potential (VEP)

2. Brainstem Auditory Evoked Potential (BAEP)

3. Somatosensory Evoked Potential (SSEP)

• Electroretinography (ERG)
• Presurgical evaluation for refractory epilepsy – LTVEEG, ictal SPECT (in coordination with department of Nuclear Medicine)
• Intra-Operative Monitoring (IOM)

E. Details of procedures

1. Electroencephalography (EEG)

The electrical activity of brain is recorded by this test. The record is analysed for abnormalities in brain rhythm. EEG is done in the following conditions:

• Epilepsy to confirm the diagnosis.
• In spells of unconsciousness/ fainting - EEG is useful in differentiating these disorders from epilepsy.
• Encephalitis (viral inflammation of brain e.g viral infections)
• Dementia.
• Stroke.
• Brain tumour.

The EEG is useful for diagnosis, to decide about medication, in monitoring the response to treatment and in long term follow up to evaluate the course of the disease.

Details of Procedure

• The test is painless.
• The patient lies on the bed quietly.
• Electrodes (small metal discs) are placed on the head.
• During the test the patient may be asked to open and close the eyes on a few occasions, may be asked to breathe rapidly for few minutes.
• The patient is encouraged to relax with eyes closed and encouraged to sleep.
• time required for preparation and actual recording may take approximately 40-60 minutes.
• There are no side effects.

Instructions

• Do not apply oil on the head.
• Take a light meal, avoid fasting.
• Take routine drugs.
• Small children and uncooperative patients may be given sedative medicine.
• This is an outpatient procedure.There is no need for admission to the hospital. Recording of electroencephalograph on a digital system

2. Portable EEG

Portable EEG is done for seriously ill patients in the ICU and wards. Recording is done bedside using an ambulatory EEG machine. The report is promptly conveyed to the treating team. Portable EEG is useful in diagnosis of the following conditions, when patient cannot be shifted to the laboratory.

• Encephalitis
• Status epilepticus
• Metabolic Encephalopathy – hepatic, renal, drug overdose
• Hypoxic brain damage
• Brain Death

3. Nerve Conduction Studies (Ncs)

Nerve conduction studies are used to evaluate the function of the nerves.

There are mainly two types of nerves - motor and sensory. The nerve conduction studies are specially designed to perform motor nerve conduction and sensory nerve conduction.

Nerve Conduction Studies Is Recommended For The Following Diseases:

• Neuropathy in patients with diabetes mellitus.
• Connective tissue diseases
• Injury to the nerves
• Carpal tunnel syndrome
• Cervical/lumbar disc prolapse
• Toxic effects of medications such as drugs taken for treatment of tuberculosis/ cancer
• Guillain Barre Syndrome
• Hereditary Neuropathy
• Myasthenia

Symptoms of nerve involvement

• Tingling, numbness of hands/feet.
• Burning sensation / pain in the hands and feet.
• Decreased sensation in arms/legs.
• Weakness /thinning of arms and legs.
• Nerve conduction study in progress

Details of Procedure

• Test usually takes 20-30minutes.
• Metal disc plates (electrodes) are placed on the skin over nerves and muscles, mild electrical stimulation is given and the response is recorded.
• Usually two nerves in upper limbs and two nerves in lower limbs are tested.
• It may be necessary to test more nerves depending on the neurological disease.

Instructions

• Wear loose clothes as this will allow easy examination.
• Fasting is not required.
• For children who are uncooperative, sedation may be required.
• There is no after effect following the test.
• This is done as an outpatient procedure.
• Technique of sensory conduction of right median nerve

4. Repetitive nerve stimulation (RNST) Repetitive nerve stimulation test is a special type of nerve conduction study. Rather than a single electric shock, a brief series of shocks is applied to a motor nerve and responses are recorded from a muscle supplied by that nerve. The study is generally performed before and after brief exercise of the muscle. Serial response amplitudes are recorded. Repetitive nerve stimulation is useful for evaluating myasthenia gravis and other disorders of neuromuscular transmission.

5. Electromyography (EMG) The EMG test is used to evaluate the status of the muscles, nerves, roots and anterior horn cells. A number of neurological disorders present with weakness or atrophy (thinning) of muscles. Some common disorders are:

• Muscular dystrophy.
• Myopathy.
• Neuropathy.
• Carpal tunnel syndrome.
• Nerve injuries.
• Cervical/lumbar radiculopathy.
• Motor neuron diseases.

The EMG may be done either alone or in combination with nerve conduction studies (NCS) depending on the neurological disorder. Common symptoms of muscle involvement:

• Difficulty in climbing stairs.
• Difficulty in getting up from sitting/squatting position.
• Difficulty in performing movements like buttoning, breaking chapatis, mixing food, combing hair.
• Raising hands above the head.

Details of Procedure

• A thin disposable EMG needle is inserted into the muscle to be examined. Depending on the type of disease one or more muscles may be required to be tested.
• You may experience mild pain during the procedure.
• There is no risk of transmitting the infection since disposable needles are used and they are destroyed after use.
• You can have your regular food and medication on the day of the test.
• You should wear loose clothes so that the test can be easily done

6. Evoked potentials (EP) Evoked potential (EP) is the electrical response recorded from brain, spinal cord or peripheral nerve evoked by various external stimuli, such as visual, auditory or somatosensory stimulation. The recording electrodes are placed over the scalp, neck or spine which vary depending on the type of stimulus modality to be tested. The evoked potential provides valuable information about the functional status and diseases affecting vision, hearing and sensory pathways.

6 a. Visual evoked potential (VEP)

VEP provides information regarding conduction in visual pathway from the retina to brain (occipital cortex).

VEP is recommended for following diseases associated with impairment of vision:

• Multiple Sclerosis
• Optic Neuritis
• Tumours of the brain (pituitary tumours)
• Head injuries
• Drugs which may cause visual impairment
• In children with mental retardation/ delayed development to assess visual status

Details of Procedure

• The test is performed in dark room.
• Each eye is tested separately.
• The patient is asked to focus on a point on the monitor, which shows checkerboard pattern.
• Small metals plates (electrodes) are applied to the head, which record the electrical potential.
• The procedure usually take approximately 30 minutes.

Instructions

• Hair should be washed, dried, with no oil, gel, spray etc.
• If the patient is using spectacles or contact lenses than he/she should wear them at the time of examination.
• For children who are uncooperative sedation may be required.
• Pattern reversal visual evoked potential in progress and Graph of visual evoked potential

Electroretinography (ERG)

ERG is performed to evaluate the visual function particularly in the patients suspected to have retinal diseases. It can be performed independently or with VEP.

6b. Brainstem Auditory Evoked Potential (BAER) This test examines the integrity of auditory pathway through the brainstem. The sound enters the ear canal and stimulates auditory nerve. The electrical impulse travels from auditory nerve through the brainstem to auditory cortex. During testing, the patient hears the repetitive click sound through the earphone.

BAER is recommended for following diseases:

• Hearing problem
• Dizziness/ Vertigo
• MultipleSclerosis
• Tumours of the Brainstem
• Head Injuries
• Delayed development in children
• Jaundice in children.

Details of Procedure

• The procedure is carried in a sound proof room.
• The stimulus is provided using headphone in one ear followed by second ear.
• The electrical response is recorded by small metal plates (electrodes).
• The test is not painful.

Instructions

• Hair should be washed, dried, with no oil, gel, spray etc.
• For children who are uncooperative sedation may be required.
• The procedure usually take approximately 30 minutes.
• Brainstem auditory evoked potential study in progess with graph

6 c. Somatosensory evoked potential (SSEP) This test examines the sensory system from the peripheral nerve to the sensory cortex of brain. Weak electrical stimuli are applied to the peripheral nerve, for example median or ulnar nerve for upper extremity study and tibial nerve for lower extremity study.

SSEP is recommended for following diseases:

• Numbness/ weakness of arm or leg.
• Diseases of the spinal cord.
• Multiple Sclerosis.

Details of Procedure

• The electrical stimulation is applied to nerve in the arm or the leg.
• The response is recorded from the neck and the head by electrodes placed over the surface.
• Mild pain is experienced when electrical stimulation is applied.

Instructions

• Should wear loose clothes, which will allow easy examination.
• Fasting not required.
• For children who are uncooperative sedation may be required.
• There is no after effect following the test.
• This is done as an outpatient procedure.

7. Video-EEG / Long term recording Video EEG monitoring is undertaken for the patients who have recurrent episodes of loss of consciousness, altered sensorium and seizures. The indications for video EEG are-

• Diagnosis of paroxysmal events including abnormal movements
• Diagnosis of non-epileptic behavioural events
• Diagnosis of seizure type/s
• Rule out combination of true and pseudoseizures

As part of presurgical evaluation for epilepsy surgery

The duration of VEEG depends on the clinical disorders, seizure frequency and indication for the video EEG. This can range from 1-3 hours in patients with frequent events (hourly) to 4-5 days in patients with infrequent events and evaluation prior to surgery. One attendant should accompany the patient during the procedure. The EEG along with the patient’s video is recorded simultaneously to evaluate the nature of events.

During events, the clinical onset and semiology of the event is noted. The EEG changes during these events are also noted. The semiology of the clinical events is correlated with the EEG abnormalities. Using this study, the ictal onset zone can be delineated. This is an important component of the presurgical evaluation for medically refractory epilepsy.

Video EEG facilities and expertise is available is only few institutions in the country. The hospital has a well-established video-EEG set-up and more than 400 such procedures have been done.

8. Intraoperative monitoring (IOM) This is performed in the operation theatre during surgery. This special monitoring is in demand during neurosurgical and orthopaedic procedures to avoid inadvertent damage to the nerves and neurological tissue in the vicinity. Intraoperative neurophysiologic monitoring minimizes neurological morbidity from operative manipulations. It identifies changes in brain, spinal cord, and peripheral nerve function prior to irreversible damage and also localizes anatomical structures, such as peripheral nerves and sensorimotor cortex. Evoked potential monitoring including SSEP, BAER, motor evoked potentials (MEP), and VEP as well as EMG is used during operative cases. IOM helps to differentiate the nerves fibers from connective tissue during surgery particularly in region of cerebellopontine angle and brain stem. The use of this technique helps to prevent complications. Similarly, SSEP is used for monitoring the preservation of spinal cord during scoliosis surgery.Intraoperative scalp EEG can be used to monitor cerebral function during carotid or other vascular surgery. Electrocorticography using subdural electrodes directly over the pial surface can help determine resection margins for epilepsy surgery, and mapping cortical function.