NEUROMUSCULAR /SENSORY STIMULATION TECHNIQUES

The term Neuromuscular technique refers to the facilitation or inhibition of muscle contraction or motor responses.

The term Sensory stimulation refers to the structured presentation of stimuli to improve (1) alertness, attention, and arousal; (2) sensory discrimination; or (3) initiation of muscle activity and improvement of movement control.

Effects are immediate and specific to the current state of nervous system.

All the facilitatory and inhibitory techniques from both neuromuscular and sensory stimulation are classified as the following:

- Proprioceptive Facilitation Techniques

- Exteroceptive Facilitation Techniques

- Vestibular Stimulation Techniques

- Augmented Visual Stimulation Techniques

- Augmented Auditory Stimulation Techniques

- Augmented Olfactory Stimulation Techniques

- Gustatory Stimulation Techniques

- Sensory Integration Techniques

I. PROPRIOCEPTIVE FACILITATION TECHNIQUES

1) QUICK STRETCH

Stimulus: Brief stretch applied to a muscle

Activates muscle spindles; sensitive to velocity and length changes.

Response: Stretch reflex: facilitates or enhances agonist muscle contraction;

Additional peripheral reflex effects: inhibits antagonists, facilitate synergists (reciprocal innervation effects).

Techniques: Quick stretch; more effective when applied in the lengthened range (eg. PNF patterns).

Adverse effects: May increase spasticity when applied to spastic muscles.

2) PROLONGED STRETCH

Stimulus: Slow, maintained stretch, applied at maximum available lengthened range.

Activates muscle spindles, Golgi tendon organs.

Response: Inhibits or dampens muscle contraction and tone due largely to peripheral reflex effect (stretch protective reflex).

Techniques: Positioning; mechanical low-load weights using traction.

3) RESISTANCE

Stimulus: A force exerted to muscle.

Activates muscle spindles and Golgi tendon organs; sensitive to velocity and length changes.

Response: Facilitates or enhances muscle contraction; enhances kinesthetic awareness.

Techniques: Manual resistance, carefully graded for optimal muscle function. Use of body weight and gravity using upright positions.

Mechanical resistance: use of weights, cuffs or vests.

Isokinetic resistance: resistance is applied to a muscle contracting at a constant rate.

Comments: Tracking (light manual) resistance is used to facilitate and accommodate to very weak muscles.

With weak hypotonic muscles, eccentric and isometric contractions are used before concentric. Maximal resistance may produce overflow from strong to weak muscles within the same muscle pattern (synergy) or to contralateral extremities.

Adverse effects: Too much resistance can easily overpower weak, hypotonic muscles and prevent voluntary movement, encouraging substitution. May possibly increase spasticity in spastic muscles.

4) JOINT APPROXIMATION

Stimulus: Compression of joint surfaces

Activates joint receptors, primarily static.

Response: Facilitates postural extensors and stabilizing responses (co-contraction); enhances joint awareness.

Technique: Manual joint compression. Elastic tubing with compression of joints during movement. Bouncing while sitting on a Swiss ball.

Comments: Approximation applied to the top of shoulders or pelvis in upright weightbearing positions facilitates postural extensors and stability (eg. Sitting, kneeling or standing)

Adverse effects: Contraindicated in inflamed joints.

5) JOINT TRACTION

Stimulus: Traction of joint surfaces.

Activates joint receptors, possibly phasic.

Response: Facilitates joint motion; enhances joint awareness, Inhibits muscle tone.

Techniques: Manual distraction. Mechanical – wrist or ankle cuffs.

Comments: Joint mobilization uses slow sustained traction to improve mobility, relieve spasm, and reduce pain.

Adverse effects: Contraindicated in hypermobile or unstable joints.

6) INHIBITORY PRESSURE

Stimulus: Deep, maintained pressure applied across the longitudinal axis of tendons; prolonged positioning in extreme lengthened range.

Activates muscle receptors (Golgi tendon organs) and tactile receptors (Pacinian corpuscles).

Response: Inhibition, dampens the muscle tone.

Techniques: Firm, maintained pressure applied manually or with positioning.

Pressure from prolonged weightbearing on knees (eg. Quadruped or kneeling) dampens extensor tone.

Pressure from prolonged weightbearing on extended arm, wrist, and fingers dampens flexor tone (eg, sitting).

Pressure over calcaneus dampens plantarflexor tone.

Mechanical: firm objects (cones) in hand, inhibitory splints or casts (wrist, legs).

Comments: Inhibitory effects can be enhanced by combination with other relaxation techniques (e.g., deep breathing techniques, soothing environment).

Adverse effects: Sustained positioning may dampen muscle contraction enough to affect functional performance (e.g., difficulty walking after prolonged kneeling).

II. EXTEROCEPTIVE STIMULATION TECHNIQUES

1) MANUAL CONTACTS

Stimulus: Firm, deep pressure of the hands in contact with the body.

Activates tactile receptors and muscle proprioceptors.

Response: Can facilitate contraction in muscle directly under the hands.

Provide sensory awareness, directional cues to movement.

Provide security and support to unstable body segments.

Comments: Can be used with or without resistance.

Adverse effects: Contraindicated over spastic muscles, and open wounds.

2) LIGHT TOUCH

Stimulus: A brief, light contact to skin.

Activates fast adapting tactile receptors.

Response: Facilitates protection and alerting responses, increased arousal; discriminative responses: identification of touch stimuli, spatial discrimination.

Techniques: Brief, light stroke of the fingertips.

Light pinch or squeezing or pressure to nail bed.

Applied to areas of high tactile receptor density (hands, feet, lips) that are more sensitive to stimulation.

Comments: Effective initially in mobilizing patients with low response levels (e.g., the patient with traumatic brain injury who is minimally responsive).

Adverse effects: Overstimulation may produce sympathetic arousal (rebound effects) with undesirable flight or fight responses.

Contraindicated for patients with generalized arousal and autonomic instability (e.g., patient with traumatic brain injury who is agitated and combative).

3) MAINTAINED TOUCH

Stimulus: Deep, maintained touch/ pressure.

Activates tactile receptors.

Response: Calming effect, generalized inhibition, decreased fight/flight response; desensitizes skin.

Techniques: Firm manual contacts.

Firm pressure to midline abdomen, back, lips, palms, and soles of feet.

Firm rubbing of midline of the back.

Comments: Useful for patients with agitation and high arousal (eg., patient with traumatic brain injury). Can be used in combination with other maintained stimuli and sensory discrimination training. Brief touch stimuli should be avoided.

4) SLOW STROKING

Stimulus: Slow stroking.

Activates tactile receptors.

Response: Calming effect, generalized inhibition, decreased tone.

Techniques: A flat hand is used to apply firm, alternating strokes in a downward direction from origin towards insertion for approximately 3 to 5 minutes.

Comments: Useful with patients who demonstrate high arousal, increased tone. Can combine with other relaxation techniques (e.g., deep breathing exercises, quiet environment). Patients with large amounts of body hair may be less responsive to calming effects; hair follicle stimulation may be irritating.

5) NEUTRAL WARMTH

Stimulus: Retention of body heat.

Activates tactile and thermoreceptors.

Response: Generalized inhibition of tone; warming produces a calming effect, relaxation, and reduction of pain.

Techniques: Wrapping body or body parts by towel or hot wraps.

Application of snug fitting clothing (gloves, socks).

Tepid baths.

Comments: Useful for patients with high arousal, or increased sympathetic activity; spasticity.

Adverse effects: Overheating should be avoided, may produce rebound effects (increased tone or arousal).

6) PROLONGED ICING

Stimulus: Cold applications.

Activates thermoreceptors.

Response: Decreases neural and muscle spindle firing. Provides inhibition of muscle tone and painful muscle.

Techniques: Immersion in cold water, ice chips, ice towels wraps or ice packs.

Adverse Effects: Contraindicated in patients with sensory deficits, generalized arousal, autonomic instability and vascular problems.

7) QUICK ICING

Stimulus: Quick Cold applications.

Activates thermoreceptors.

Response: Increases neural firing. Stimulates muscle tone.

Techniques: Performed with the tip of the ice cube, rubbed fast along the length of the muscle to be stimulated from its insertion towards origin.

Comments: Careful about the tip of ice cube not to injure the area. Water formed at that area should be cleaned.

Adverse Effects: If performed for longer time than the area may cool down thus producing the opposite of the desired effect.

III. VESTIBULAR STIMULATION TECHNIQUES

1) SLOW VESTIBULAR STIMULATION

Stimulus: Low-intensity, slow and rhythmic vestibular stimulation.

Activates primarily otolith organs (tonic receptors); lesser effects on semicircular canals (phasic receptors) with inputs via Cranial Nerve VIII (Vestibulo-Cochlear) to CNS higher centers and spinal cord.

Response: Generalized relaxation: inhibition or dampening of tone and motor output (Vestibulospinal reflexes); decreased arousal, fight/flight responses.

Techniques: Passive, manually assisted or active motions: slow, repetitive rolling or rocking movements, e.g., sidelying rolling, sitting rocking.

Mechanical: use of a rocking chair or bed, therapy ball or bolster, equilibrium board; wheelchair ride.

Comments: Useful with patients who are hypertonic, hyperactive, or who demonstrate tactile defensiveness.

Can be combined with other relaxation techniques (e.g., deep breathing exercises, quiet environment).

2) VESTIBULAR STIMULATION

Stimulus: Vestibular stimulation via head and body movements.

Activates semicircular canals (phasic receptors that detect rotational acceleration and deceleration), otolith organs (tonic receptors that detect head position with respect to gravity and linear acceleration) with inputs via Cranial Nerve VIII to CNS higher centers.

Response: Postural and Tonal adjustments. Head and eye movements. Improvement of motor coordination. Generalized arousal.

Techniques: Change of position or movement. Fast spinning and linear movements with acceleration and deceleration components heightens alertness and motor responses (e.g., spinning in a chair, prone on a scooter board).

Mechanical: equilibrium boards, wobble boards, therapy balls etc.,

Comments: Useful with Hypotonic patients (eg., patients with Down syndrome), patients with sensory integrative dysfunction, patients with coordination(eg., stroke, cerebral palsy), helpful in overcoming he effects of akinesia or bradykinesia (Parkinson’s disease).

Adverse Effects: Prolonged effects may include behavioral changes, seizures, and sleep disturbances.

IV. AUGMENTED VISUAL STIMULATION TECHNIQUES

Stimuli:

Visual objects: pen light, brightly colored blocks, familiar objects, photo card.

Visual backgrounds: checkerboard background, moving surround screen

Videotapes

Visual biofeedback

Activates photoreceptors (rods and cones) with inputs via Cranial Nerve II (Optic) to CNS higher centers (lateral geniculate nucleus, primary visual cortex in the occipital lobe, association areas).

Response:

Visual discrimination: conscious awareness and recognition of objects; visual tracking.

Alerting, orienting responses: startle response to an unexpected visual stimulus.

Visual proprioception: processes information about body in space and spatial relationships.

Contributes to control motor responses: active movements, postural/tonal adjustments.

Techniques:

Structured application of visual stimuli: presentation of visual objects: vary colors, size, distance, and orientation.

Moving visual targets.

Environmental- altered lighting:

- Soft lights and cool colors for promotion of relaxation (e.g., the patient with traumatic brain injury and confused/agitated response levels)

- Bright lights, bright colors, and repetitive even patterns for generalized stimulation of consciousness, attention, and alertness (e.g., a patient with traumatic brain injury with decreased response levels)

Visual biofeedback can be used to aid movement control, strength of muscle contraction, or muscle relaxation.

Comments:

Visual scanning activities are important for patients with hemianopsia. Elimination of extraneous visual stimuli and visual distractors using a quiet or closed environment may be necessary to ensure patient attention and visual perception.

Utilize gradual reintroduction of distracting visual stimuli in a variable or open environment as recovery permits.

Adverse Effects:

Avoid sensory overload, irritating stimuli that may cause agitation.

Altered or decreased visual perception occurs with busy, open clinic environments; visual distractors or sudden, unexpected visual stimuli disrupt motor performance.

V. AUGMENTED AUDITORY STIMULATION TECHNIQUES

Stimuli:

Verbal commands (VCs)

Variable sounds: rattle, cluster bells

Audiotapes: familiar music or voices

Auditory biofeedback

Activates cochlear receptors via CN VIII (Vestibulocochlear) to CNS higher centers (cochlear nucleus, reticular formation, inferior colliculus, and medial geniculate body)

Response:

Auditory discrimination: conscious awareness and recognition of sounds,

Auditory tracking responses .

Alerting, orienting responses: startle response to a loud noise.

Motor responses: active movement responses,

Postural/tonal adjustments.

Relaxation responses

Techniques:

Structured application of auditory stimuli: presentation of varying sounds.

With VCs: consideration of pitch, tone, and level of volume is important; adaptation occurs with constant volume.

Relaxing, soft, familiar music aids relaxation and reduction of tone.

Rhythmic auditory stimulation and brisk music aids movement initiation and the development of timing and rhythm of a movement sequence (eg., marching music for patients with Parkinson’s disease).

Auditory biofeedback can be used to aid movement control, strength of muscle contraction, or muscle relaxation.

Comments:

Precise, dynamic VCs are an important element of PNF.

Positive emotional effects occur with VCs that are motivating and encouraging.

Elimination of extraneous noise and auditory distractors using a quiet or closed environment may be necessary to ensure patient attention and auditory perception.

Utilize gradual reintroduction of distracting auditory stimuli in a variable or open environment as recovery permits.

Adverse Effects:

Avoid sensory overload, irritating stimuli that may cause agitation.

Altered or decreased auditory perception occurs with busy, open clinic environments; auditory distractors or sudden, unexpected auditory stimuli disrupt motor performance.

Negative emotional effects occur with VCs that express anger and frustration.

VI. AUGMENTED OLFACTORY STIMULATION TECHNIQUES

Stimuli: Varying odors that stimulate the sense of smell.

Pleasant odors: Vanilla, perfume, favorite foods.

Stimulant odors: ammonia, vinegar.

Activates nasal olfactory receptors (fast adapting) to Cranial Nerve I (Olfactory) to temporal and frontal lobes without synapsing in thalamus, higher centers.

Response:

Relaxation responses with pleasant, familiar odors: Reduction of tone and hyperkinetic movements.

Alerting, orienting, arousal responses with noxious odors: Motor responses- active movement responses, postural/tonal adjustments.

Techniques:

Structured application of stimuli: presentation of varying odors.

Comments:

Consider patient’s premorbid interests and likes as well as odors in the external environment and scents you are wearing.

Adverse Effects:

Avoid sensory overload; irritating stimuli that cause agitation.

Contraindicated in patients with hypersensitivity.

VII. GUSTATORY STIMULATION TECHNIQUES

Stimuli: Taste stimuli.

Activates taste receptors on posterior tongue to Cranial Nerve IX (Glossopharyngeal); anterior and sides of tongue to Cranial Nerve X (Vagus) and Cranial VII (facial) to higher centers (temporal lobe).

Response:

Recognition of tastes; fast adapting

Techniques:

Structured application of stimuli: presentation of varying tastes.

Feeding is a multisensory experience including taste, smell, pressure, texture, and temperature.

Comments: Various foods evoke emotional contexts.

Adverse Effects:

Dysphagia management requires careful control of food inputs (e.g., taste, texture, size).

VIII. SENSORY INTEGRATION TRAINING

Stimuli:

Multimodal: varied sensory stimuli are presented in the context of meaningful activities (tactile, vestibular-proprioceptive, and visual).

Activates sensory receptors and higher brain centers: engages central processing areas of sensory information.

Response:

Improved sensory discrimination: identification of specific stimuli (e.g., shapes, weights, texture, numbers written on skin), intensities, and improved ability to localize stimuli.

Improve perception: selection, attention, and response to sensory inputs with appropriate use of information to generate specific motor responses.

Techniques:

Tactile: deep touch-pressure activities (e.g., stroking or rubbing the skin, use of a vibrator, manipulation and identification of objects, drawing letters on skin)

Vestibular-proprioceptive: activities designed to stimulate a variety of movement experiences (e.g., linear and accelerated movements, resisted movements, gasping and moving objects, throwing objects, therapy ball or wobble board activities).

Visual: visual cues, tracking tasks.

Comments:

Sensory training is an important component of balance training: activities focus on isolating and combining different inputs under varying conditions.

Used for patients with sensory integrative dysfunction who have a poor ability to discriminate touch, movement, force, or information about their bodies.