Summary of Neurophysiological Principles Flashcards
Summary of Neurophysiological Principles
After Discharge • Temporal Summation • Spatial Summation • Irradiation • Successive Induction • Reciprocal Innervation (Inhibition) • Autogenic Inhibition
After discharge:
- Any somatosensory stimulation (touch, pressure, proprioception) has a continuation of the stimulus after cessation of stimulation.
- The greater the stimulus, the greater the discharge.
Temporal Summation:
• Repeated stimuli (generally weaker)
• Occurring within a short period of time
• Combine to cause excitation
(CONTINOUSLY STABBING SOMEONE AT SAME SPOT)
Spatial Summation:
DIFFERENT SPACES/LOCATIONS AT SAME TIME
• Weak stimuli applied to different areas of the body simultaneously.
• Reinforces the facilitatory effect to cause excitation.
Irradiation:
• Spreading of the response>overflow from stronger muscle groups to weaker muscle groups.
• Increased strength of the response.
• Increased number of stimuli OR Increased intensity of stimulus.
* HAVE STRONGER MUSCLES HELP WITH RECRUITMENT
Successive Induction:
- Strong contraction of the antagonist muscle (muscles opposing the action) causes reciprocal inhibition of the agonist (muscles contributing to the desired direction of movement).
- Once the antagonist relaxes, the inhibition ceases and there is an increased excitation of the agonist.
Reciprocal Innervation (Inhibition):
• Contraction of muscles leads to simultaneous relaxation (inhibition) of their antagonists.
Example - Reciprocal inhibition in stretch reflex:
• Joints are controlled by opposing muscle groups (flexors / extensors).
• When a muscle spindle stretches and activates the stretch reflex, the opposing muscle group needs to be inhibited so that it doesn’t work against the contraction of the desired muscle.
• Remember muscle spindles lie within the muscle belly and respond to stretch (changes in muscle length).
Autogenic Inhibition:
- Reflex relaxation that will occur in the same muscle that the Golgi tendon organ is stimulated in (this occurs by isometrically contracting a stretched muscle)a - Lowers resistance to stretch therefore can increase ROM.
- Remember, GTO are located in muscle tendons and respond to force / muscle tension.
TECHNIQUES
Facilitatory – used to gain muscle activity Example: Mm strength, mm endurance, coordination
Inhibitory – used to reduce muscle activity Example: Increase range, decrease tone
PNF TECHNIQUES
• Methods by which the patterns of movement are applied to achieve various responses.
• PNF uses concentric, eccentric and isometric muscle contractions combined with suitable resistance and specific facilitatory techniques.
• Examples:
– Use facilitation to increase strength and / or stability.
– Use inhibition combined with facilitation to increase range.
• Treatment goals can include:
– Increase ROM
– Increase strength
– Develop co-ordination
– Reduce fatigue
– Decrease pain
Facilitation
- Utilise facilitatory neurophysiological principles – after discharge, temporal and spatial summation, irradiation, successive induction
- Physiotherapists can utilise facilitation techniques to make movement easier and more accurate for patients.
- The accuracy in movement is imperative in prevention of musculoskeletal injuries, and also vital for efficient functioning.
- Treatment methods / approaches that use facilitation methods include PNF (Kabat, Knott & Voss), Bobaths, Rood, Ayres and Sahrmann.
When is facilitation appropriate?
If you are trying to get a muscle contraction when it is difficult for the patient to contract the muscle due to:
– Weakness – Pain
– CNS damage
– Abnormal recruitment patterns
Facilitation Specific Techniques
• Rythmic initiations • Slow reversals • Slow reversals hold • Repeated contractions • Rhythmic stabilisations (Listed in order of typical progressions)
Rhythmic Initiation
- Assists patient to initiate movement (e.g. apraxic patient)
- ALWAYS start with this to ensure the patient understands the movement and is performing correctly.
- Improves co-ordination and sense of motion
- Normalizes the rate of motion
- Teaches the motion
- Can help the patient relax
- Can classify as a ‘strengthening’ exercise in very low level patients
Rhythmic Initiation
Application:
- Passively move the limb / part through full available range in the PNF pattern.
- Patient watches / concentrates on feeling the movement.
- Ask the patient to assist your movement (or may ask them to do it themselves if strong enough) to ensure they have understood.
- Progression > Slow reversals.
Slow Reversals
- Can be used for improving muscular strength
- Can be used for improving muscular endurance
- Can be used to facilitate normal timing between agonists and antagonists.
- Example = Useinpatientswithmuscleweakness.
Slow Reversals Application:
• If you have gone through rhythmic initiation and the patient is tolerating ok,
then you can add resistance to the agonist and antagonist patterns through full available range > this becomes a slow reversal technique
• Start in direction of pattern with weaker muscle groups (isotonic contraction of agonists)
• Smoothly reverse into antagonist pattern (isotonic contraction of antagonists). Repeat.
• MAXIMISE all sensory inputs – voice, touch, visual cues
• Progression > Slow reversal holds
Slow Reversals Hold
• Used to increase the motor unit recruitment and strength at a particular point in the motion
• Might add/progress to repeated contraction application to enhance the HOLD
Application:
• An isometric hold is applied at any point in the execution of a diagonal pattern of movement where muscle response is less / weaker.
Repeated Contractions
• Enhances recruitment of motor units.
• Used mainly when muscle WEAKNESS is a problem or when initiation of movement is difficult.
Advantages:
• Learning and skill acquisition occurs through repeated stimulus of CNS: o Allows focus to specific muscle / group of muscles.
o Uses repeated stretch of muscle spindle to recruit motor units. o Focus on voluntary contraction response.
• Enables increased strength / endurance in very weak muscles.
• When fatigue of muscle response is evident, you MUST stop and allow recovery.
Repeated Contractions
Application:
Move out of the agonist pattern a short amount (+stretch stimulus) à initiate command to move into agonist pattern again
Commands:
• Now PULL (apply stretch and resist flexion)
• Or now PUSH (apply stretch and resist extension)
Rhythmic Stabilisations
• Used to gain stability and increase endurance.
Example = In a patient with poor globa land/or local stability.
• Aims to gain isometric contraction of agonists and antagonists to provide joint/s stability.
• Particularly useful if there is PAIN when motion is attempted.
• Prescription guideline: 10 x 10 second holds
Rhythmic Stabilisations APPLICATION:
- Get the patient to perform an isometric contraction of the agonist/s.
- Following this, get the patient to perform an isometric contraction of the antagonist/s.
- Do NOT apply too much resistance – contraction is isometric & aims for co- contraction.
PNF AIMS
PNF aims to combine the many facilitatory factors such as sight, hearing, touch, pressure and resistance to give a bigger sensory demand and so a bigger motor response is elicited.
