tone Flashcards
what is tone?
the resistance offered by muscles to continuous passive stretch
(resistance encountered when a joint of a relaxed person is moved passively)
what are examples of non-neural factors contributing to tone?
-passive stiffness of a joint & surrounding tissue
-compliance of muscles, ligs and joints
-age
-exercise state
-limb temperature
what are examples of neural factors that can affect tone?
-can vary with age, emotional state
-output of alpha motor neuron
-active tension set up by stretch reflex
what are examples of peripheral and central systems that contribute to tone?
-muscle spindles (part of stretch reflex)
-golgi tendon organ
-somatosensory receptors
-sensory systems - visual, auditory, vestibular
-limbic system
-motor systems
what is the stretch reflex?
the body’s involuntary response to an external stimulus that stretches the muscles
what is the function of muscle spindles?
provide info regarding muscle length and rate of change of length
what is a stretch reflex a direct result of?
stimulation of the muscle spindle (stretch receptor)
what is the sequence of events in a stretch reflex once a muscle spindle is activated?
what are the steps of stretch reflex in simple terms
-stretching of muscle stimulates muscle spindles
-activation of sensory neuron
-info processing of motor neuron
-activation of motor neuron
-contraction of muscle
where are the gamma motor neurons located in the muscle spindle?
the intra-fugal fibres
what is the basic function of the muscle spindle?
helps to maintain muscle tone
what can abnormal PROM of joint be due to?
-joint stiffness
-reduced muscle/ tendon length
-tone
-patient activity
what is high tone and low tone called?
-hyperTonia , spasticity, rigidity
-hypotonia, flaccidity
what is spasticity?
-velocity dependent increase in resistance to passive stretch of a muscle with exaggerated tendon reflexes
why does spasticity happen?
-abnormal enhancement of spinal stretch reflex - due to increased muscle spindle sensitivity, loss of inhibition of stretch reflex
-central - loss of cortical inhibition, imbalance in descending pathways
-peripheral - altered biomechanics properties of muscles
what causes a spasticity?
-upper motor neuron lesion (from motor cortex to spinal motor neuron)
-stroke
-spinal cord compression
-brain damage
-MS
describe the clinical features of spasticity
-increased responsiveness of muscles to stretch- hyper-reflexia
-clasp knife(catch) followed by melting away of resistance
-clonus (rhythmic contractions) usually of ankle or foot
-associated reactions - unwanted movement which is brought on by increased tone eg yawning and arm goes up
recap - what are the common patterns of spasticity in the upper limbs?
-adducted / internally rotated shoulder
-flexed wrist
-pronated forearm
-flexed elbow
-thumb in palm deformity
what are common patterns of spasticity in the lower limbs?
-striatal toe
-stiff knee
-flexed knee
-adducted thighs
equinovarus
what are factors that influence spasticity?
-positioning
-stress
-fatigue
-full bladder
-pain
-infection
-fear
-pressure sore
-constipation
how do you assess abnormal tone?
-ash worth scale or tardieu
-movement grading - severe, moderate, mild
-tendon jerks - +/ ++
-others such as EMG
how do we manage spasticity?
-relieve symptoms
-handling / positioning
-standing frames
-avoid noxious stimuli
-splinting
-slow passive movements
-medication
list some examples of medication used to treat spasticity
-baclofen (lioresal) - GABA deriative
-diazepam (valium). - GABA
-botulium toxin (dysport) injected into muscle - blocks ACH release
-tizanidine (zanaflex) - short acting muscle relaxer
how does spasticity affect the patient?
-weakness
-decreased movement
-abnormal movement
-poor posture
-pain
-contractures
-loss of function and adaptive
in terms of spasticity, what are the aims of physiotherapy?
-normalise the tone
-maintain normal muscle length
-improve ROM
-decrease pain
-improve function
-reduce complications
describe the physio management of spasticity ?
-positioning of limb - to reduce abnormal reflex activity - NB sitting out
-passive movement SLOW of affected limb
-ice
-weight bearing
-splinting
-pain management
what is rigidity?
-increased resistance to los passive movement which is CONSTANT through out full ROM
what’s the difference between lead pipe rigidity and cogwheel rigidity?
lead pipe - resistance felt throughout movement
-cogwheel - presence of additional tremor
what is the pathophysiological mech of rigidity?
normal stretch reflex is composed of short latency (spinal) and long latency (brain) - the longer the latency the greater the rigidity
what are causes of rigidity?
-extrapyramidial lesions
-parkinsons
what are the clinical features of rigidity?
-increased resistance to relatively slow imposed passive moments
-lead pipe resistance (throughout ROM)
-tendon reflexes are normal
-can have superimposed tremor - leading to cogwheel rigidity
how is rigidity assessed?
usually scales tend to be disease or condition specific eg parkinsons - foehn and yahr scale
what does the physio management of rigidity involve?
-assessment and regular re assessment
-normalise tone
-manage of stiffness and pain( heat, stretch etc )
-gait, mobilioty transfers - re-education
-re educate about posture
what is hypotonia?
low state of tone
what are the characteristics of hypotonia?
-decreased resistance to passive movement
-decreased reflexes
what are the causes of hypotonia?
-central cerebral shock - after UMNL
-spinal shock after spinal cord injury
-peripheral nerve lesion
-cerebellar
what is the pathophysiological mech of hypotonia
-not clear
-can be due to neural shock
-prolonged hypotonia 0 reduced level of arousal
what effect does hypotonia have on patients?
-loss of function
-inability to move against gravity
-inability to sustain upright posture
-muscle is prone to atrophy
-inability to weight bear and transfer
what is the aim of physio for hypotonia?
-protect limb and joint eg splints
-sensory input - sitting balance, tapping, ice brushing, tapping, stroking - sensory re education
-positioning- optimal level of support
-promote tone
-education and awareness to patient and carers
what is serial casting used for ?
it helps to decrease muscle tightness and allow for better function and mvt of a joint
