Neurophysiological Techniques in Pediatrics

1. Electroencephalography (EEG)

Standard EEG

• Records spontaneous cortical electrical activity via scalp electrodes (10–20 system).
• Key pediatric uses: seizure disorders (epilepsy workup), encephalopathies, sleep disorders, brain death determination.
• Pediatric considerations:
  • Normal EEG patterns evolve with age (e.g., posterior dominant rhythm starts at ~3–4 Hz in infancy, reaching adult 8–13 Hz alpha by ~8 years).
  • Hypsarrhythmia (chaotic high-amplitude pattern) is hallmark of Infantile Spasms (West Syndrome).
  • CSWS (continuous spike-wave during slow-wave sleep) is a peds-specific pattern.

Prolonged / Video-EEG (vEEG)

• Simultaneous video and EEG recording for seizure semiology and electroclinical correlation.
• Gold standard for epilepsy surgery workup and differentiating epileptic vs. non-epileptic events.

Ambulatory EEG

• 24–72 hour portable recording; useful in older cooperative children.

Neonatal EEG

• Detects neonatal seizures (often clinically silent), guides treatment in HIE (hypoxic-ischemic encephalopathy).
• Amplitude-integrated EEG (aEEG) is a simplified bedside tool used in NICUs to monitor background activity and detect burst-suppression patterns.

2. Nerve Conduction Studies (NCS)

• Measures conduction velocity, amplitude, and latency of sensory and motor nerve fibers.
• Pediatric uses: peripheral neuropathies (CMT, GBS, CIDP), birth brachial plexus palsy, entrapment neuropathies.
• Key pediatric adjustments:
  • Normal values are age-dependent — myelination is incomplete at birth and reaches adult values by ~3–5 years.
  • Neonates and infants have significantly slower conduction velocities (~half adult values).
  • Electrode distance must be adjusted for limb length.

3. Electromyography (EMG)

• Needle electrode inserted into muscle to record electrical activity at rest and during voluntary contraction.
• Findings:
  • Fibrillations/positive sharp waves → denervation (lower motor neuron / axonal)
  • Myotonic discharges → myotonic dystrophy (important pediatric condition)
  • Decreased motor unit recruitment → neuropathic
  • Short-duration, polyphasic MUPs → myopathic pattern (muscular dystrophies, inflammatory myopathies)
• Pediatric considerations: requires sedation or careful technique in young/uncooperative children; results may be limited by poor activation.

4. Repetitive Nerve Stimulation (RNS)

• Motor nerve stimulated at low (2–3 Hz) or high (30–50 Hz) frequency; compound muscle action potential (CMAP) recorded.
• Low-frequency RNS:
  • Decremental response (>10%) → Myasthenia Gravis, Congenital Myasthenic Syndromes (CMS)
  • Incremental response → Lambert-Eaton Myasthenic Syndrome (rare in peds)
• Critical for diagnosing neuromuscular junction (NMJ) disorders and Botulism in infants (Infant Botulism: facilitation at high-frequency RNS).

5. Evoked Potentials (EPs)

a. Visual Evoked Potentials (VEP)

• Flash or pattern-reversal stimulation → records P100 wave from occipital cortex.
• Uses: optic neuritis, visual pathway integrity, cortical visual impairment (CVI), evaluation of vision in non-verbal infants.

b. Brainstem Auditory Evoked Potentials (BAEPs / ABR)

• Click stimulus → records waves I–V from auditory brainstem pathway.
• Uses:
  • Universal Newborn Hearing Screening
  • Posterior fossa/brainstem lesion monitoring (e.g., Chiari malformation decompression surgery)
  • Hearing threshold estimation in children who cannot undergo behavioral audiometry
  • Acoustic neuroma, demyelinating disease (MS)

c. Somatosensory Evoked Potentials (SSEPs)

• Peripheral nerve electrically stimulated → cortical and subcortical responses recorded.
• Uses:
  • Spinal cord monitoring during scoliosis surgery (Harrington rod/spinal fusion)
  • Cervical myelopathy
  • Prognostication after HIE/cardiac arrest
  • Brachial plexus injury assessment

d. Motor Evoked Potentials (MEPs)

• Transcranial magnetic (TMS) or electrical stimulation of the motor cortex → muscle response recorded.
• Uses:
  • Intraoperative monitoring of motor tracts (combined with SSEPs in spine/brain surgery)
  • Corticospinal tract integrity in cerebral palsy, spinal cord disorders

6. Intraoperative Neurophysiological Monitoring (IONM)

• Alert criteria: >50% amplitude decrease or >10% latency increase in SSEPs/MEPs triggers surgical reassessment.

7. Transcranial Magnetic Stimulation (TMS)

• Non-invasive cortical stimulation using magnetic pulses.
• Research and clinical uses in peds:
  • Mapping motor cortex before epilepsy/tumor surgery
  • Assessing corticospinal excitability in cerebral palsy
  • Therapeutic (repetitive TMS) in depression (adolescents) and motor rehabilitation

8. Polysomnography (PSG)

• Multi-channel overnight sleep study (EEG, EMG, EOG, respiratory channels, pulse oximetry).
• Pediatric uses: obstructive sleep apnea (OSA), central apnea, narcolepsy, parasomnias, nocturnal seizures.
• Normative values for sleep architecture differ significantly from adults (neonates spend ~50% in REM).

Summary Table

Clinical Pearl: In pediatrics, age-appropriate normative data are mandatory for all electrodiagnostic studies. A value normal in an adult may be frankly abnormal in a toddler, and vice versa, due to ongoing myelination and CNS maturation.

Neurophysiological Techniques in Pediatric Physiotherapy

Core Neurophysiological Approaches

1. Neurodevelopmental Treatment (NDT) / Bobath Concept

• Developed by: Karel and Berta Bobath (1940s–50s)
• Principle: Abnormal postural tone and movement patterns can be inhibited, and normal movement facilitated through specific handling techniques. Emphasizes neuroplasticity and task-specific practice.
• Key techniques:
  • Key Points of Control (KPC): Proximal (shoulder girdle, pelvis) or distal (hands, feet) points used to influence tone and movement throughout the body.
  • Facilitation: Guiding the child toward normal movement patterns.
  • Inhibition: Reducing spasticity and abnormal reflex activity (e.g., reflex inhibiting postures/patterns — RIPs).
  • Weight-bearing and alignment: Promotes normal proprioceptive input through correct joint positioning.
• Used in: Cerebral palsy (all types), hemiplegic children, hypotonic infants.
• Goal: Functional independence through quality of movement.

2. Vojta Therapy (Reflex Locomotion)

• Developed by: Václav Vojta (1960s–70s)
• Principle: Stimulation of specific body zones (trigger points) in defined reflex positions activates innate, genetically pre-programmed locomotion patterns (reflex creeping and reflex rolling) stored in the CNS.
• Two core patterns:
  • Reflex Creeping (prone position)
  • Reflex Rolling (side-lying position)
• Stimulation zones: 10 zones on thorax, extremities, and face. Pressure applied by therapist (or trained parents).
• Effect: Activates global muscle activation patterns, trunk stabilization, respiratory muscles, and orofacial musculature simultaneously.
• Used in: Infantile cerebral palsy, hypotonia, brachial plexus birth palsy, hip dysplasia, torticollis, developmental delay — particularly effective in infants (0–12 months).
• Advantage: Parents trained to apply 3–4 times daily at home.

3. Proprioceptive Neuromuscular Facilitation (PNF)

• Developed by: Kabat, Knott, and Voss
• Principle: Uses proprioceptive input (stretch, resistance, joint approximation/traction) to facilitate or inhibit neuromuscular responses. Leverages diagonal and rotational movement patterns reflecting natural limb movements.
• Key PNF patterns:
  • Upper extremity: D1 (flexion/adduction/external rotation) and D2 (flexion/abduction/external rotation)
  • Lower extremity: D1 and D2 similarly
• Techniques:
  • Rhythmic Initiation: Passive → active-assisted → active movement to initiate movement in hypertonic or rigid patients.
  • Repeated Contractions: Repeated stretch reflex to reinforce weak muscles.
  • Hold-Relax / Contract-Relax: Proprioceptive stretching to gain ROM, particularly in spastic muscles.
  • Rhythmic Stabilization: Isometric co-contraction for trunk/proximal stability.
• Used in: Older cooperative children with CP, hemiplegia, ataxia, post-trauma; trunk stabilization in scoliosis.

4. Rood Approach

• Developed by: Margaret Rood
• Principle: Sensory stimulation of skin and muscles influences motor output; sensation precedes and drives motor control. Uses facilitory and inhibitory sensory inputs.
• Facilitory techniques (increase tone/activity):
  • Fast brushing (C-fiber stimulation → sustained muscle activation after 30–40 min latency)
  • Icing (brief application)
  • Tapping over muscle belly or tendon
  • Light moving touch
  • Vibration (low frequency)
• Inhibitory techniques (decrease tone/spasticity):
  • Slow stroking (posterior primary ramus area, midline back)
  • Sustained pressure (to tendons, palms, soles)
  • Neutral warmth (wrapping in warm blanket)
  • Slow rolling/rocking
  • Deep pressure
• Developmental sequence: Treatment follows ontogenetic developmental order (supine → prone → sitting → standing).
• Used in: Spasticity management, hypotonia, sensory processing disorders.

5. Brunnstrom Approach

• Developed by: Signe Brunnstrom
• Principle: Uses synergistic movement patterns (flexor and extensor synergies) as a stepping stone toward voluntary movement recovery. Embraces early-stage abnormal synergies rather than suppressing them.
• Stages of recovery (Brunnstrom): 1 (flaccidity) → 6 (near normal)
• Techniques:
  • Tonic reflexes (ATNR, STNR, TLR) used therapeutically to facilitate movement.
  • Proprioceptive and exteroceptive stimuli to trigger synergies.
  • Progress toward breaking out of synergy patterns.
• Used in: Pediatric hemiplegia (e.g., hemiplegic CP, post-stroke adolescents), recovery from TBI.

6. Sensory Integration Therapy (Ayres Sensory Integration — ASI)

• Developed by: A. Jean Ayres
• Principle: The brain must organize and integrate sensory information (tactile, proprioceptive, vestibular) for adaptive motor and behavioral responses. Dysfunction in sensory integration underlies many motor and behavioral problems.
• Key sensory systems addressed:
  • Vestibular: balance, spatial orientation, eye-head coordination
  • Proprioceptive: body awareness, muscle tone regulation, motor planning
  • Tactile: discrimination, defensive responses
• Techniques: Suspended equipment (swings, hammocks), resistive activities (heavy work), textured surfaces, obstacle courses — all within a child-directed, play-based framework.
• Used in: ASD, developmental coordination disorder (DCD), ADHD, learning disabilities, sensory processing disorder.

7. Constraint-Induced Movement Therapy (CIMT)

• Principle: Restraint of the less-affected upper limb combined with intensive, task-specific training of the affected limb forces use and promotes cortical reorganization (neuroplasticity).
• Pediatric adaptations:
  • Pediatric CIMT (pCIMT): 6+ hours/day constraint, intensive therapy
  • Modified CIMT (mCIMT): Less intense constraint (<6 hrs), more feasible in young children; often combined with bimanual training
  • Hand-arm bimanual intensive therapy (HABIT): Complement to CIMT
• Used in: Hemiplegic CP, perinatal stroke
• Evidence: Strong evidence for improving upper limb function in hemiplegia

8. Treadmill Training / Body Weight-Supported Treadmill Training (BWSTT)

• Principle: Partial unweighting via harness allows repetitive stepping with correct gait kinematics, exploiting spinal CPG (Central Pattern Generator) circuits to drive neuroplastic change.
• Used in: CP (all GMFCS levels), spinal cord injury, Down syndrome, post-TBI
• Evidence: Improves walking speed, endurance, and gross motor function in CP.

9. Biofeedback (EMG Biofeedback)

• Surface EMG electrodes provide real-time visual/auditory feedback of muscle activation.
• Helps children learn voluntary control of weak or spastic muscles.
• Used in: Foot drop in CP, gait training, improving selective motor control.

10. Neuromuscular Electrical Stimulation (NMES) & Functional Electrical Stimulation (FES)

• NMES: Electrical current applied to elicit muscle contraction; strengthens weak muscles, reduces spasticity, improves joint ROM.
• FES: Stimulation synchronized with movement to produce functional motor activity (e.g., peroneal stimulator for foot drop during gait).
• Used in: CP, spinal cord injury, brachial plexus palsy.

11. Transcutaneous Electrical Nerve Stimulation (TENS)

• Low-intensity electrical stimulation for analgesia (pain modulation via gate control theory).
• Used in post-surgical pain, musculoskeletal pain in older children.

Comparison of Major Approaches

Common Pediatric Conditions & Techniques Used

Key Principle Across All Approaches: Neuroplasticity is greatest early in life. Intensity, task-specificity, repetition, and early intervention are the common denominators that drive optimal neurological recovery in pediatric physiotherapy.