The cause of falls and why older people are more at risk Flashcards
Define balance?
The ability to maintain the line of gravity passing through the centre of gravity (COG) within the base of support (BOS)
Define Centre of Gravity (COG)?
Point in space where total body weight is concentrated/acts
Where is a person’s COG located?
Immediately anterior to upper sacrum
Define line of gravity?
Imaginary vertical line passing from the centre of gravity of an object down to the ground
Define Base of Support (BOS)?
Area beneath object/person that includes every point of contact they make with the supporting surface
Do contact points of BOS have to be body parts?
No
Contact points include body parts eg. hands, feet and inanimate objects eg. crutches, chair that person is sat in
Define stable vs unstable balance?
Stable balance: Line of gravity is inside BOS
Unstable balance: Line of gravity is outside BOS
Define postural sway, and what is its function?
Horizontal balance-seeking movements around COG
To correct unstable balance by moving body so that line of gravity is inside BOS again
In forwards postural sway, what balance-seeking movements occur, and what is the position of the imbalanced, unstable person?
Movement to pull COG back and down
to correct forwards and upwards imbalance
In backwards postural sway, what balance-seeking movements occur, and what is the position of the imbalanced, unstable person?
Movement to pull COG forward and up
to correct backwards and downwards imbalance
Describe the ankle strategy for correcting forwards and backwards postural sway?
Muscles on front of ankle contract to pull COG forward in backwards sway
Muscles on back of ankle contract to pull COG backward in forwards sway
When is the ankle strategy used to correct postural sway, in terms of the line of gravity and BOS?
For ‘small’ imbalances, when line of gravity is still within BOS and is being maintained
Describe the hip strategy for correcting forwards and backwards postural sway?
Hip joints quickly extend and arms extend up and forward (limbo position) to correct backwards sway
Hip joints quickly flex and arms extend up and back (‘bow’) to correct forwards sway
When is the hip strategy used to correct postural sway, in terms of the line of gravity and BOS?
‘Medium’ imbalances where line of gravity/COG is at edges of BOS
Describe the stepping strategy for correcting postural sway?
Take steps to change position of feet and establish new BOS which line of gravity will now fall in
When is the stepping strategy used to correct postural sway, in terms of the line of gravity and BOS?
‘Large’ imbalances where line of gravity/COG has exceeded past BOS
Describe the reaching/grabbing strategy for correcting postural sway?
Reaching out and grabbing anything nearby to prevent falling down
When is the reaching/grabbing strategy used to correct postural sway, in terms of the line of gravity and BOS?
Used when ankle, hip, stepping strategies didn’t correct imbalance
In the inner ear, which 2 receptor organs are part of the vestibular system, for balance control?
Otolith organs
Semicircular canals
What are the 2 otolith organs in the inner ear, and which physiological system are they a part of to control balance?
otolith organs: saccule and utricle
Part of vestibular system
What is the other name for otolith organs, and why?
gravity receptors (Type of vestibular receptor organ that responds to gravitational forces)
What do otolith organs detect, and what receptors detect stimuli?
Contain macula which contain hair cells (receptor)
detect linear acceleration of head
What do semicircular canals detect, and what receptors detect stimuli?
Contains crista which contain hair cells
detect angular and rotational acceleration of head
Why does ageing make vestibular reflexes initiated by otolith organs and semicircular canals slower and less accurate?
Ageing reduces number of hair cells and nerve fibres
What info does the thalamus process, and why does it then send processed info to cerebral cortex?
Thalamus processes all info about body senses like balance (except smell)
then sends it to cerebral cortex for interpretation
What info does brainstem receive from the cerebral cortex and cerebellum?
mostly about past experiences that have affected sense of balance
Which tracts carry spinal cord input to the cerebellar cortex, and what is the input?
Spinocerebellar tracts
Input is proprioceptive info (sense of actions, movement and location of body parts) from lower limbs and trunk
Which 2 body regions detect proprioceptive info, which is transmitted as spinal cord input to cerebellar cortex, in balance control?
Lower limbs
Trunk
How does ageing affect integration of balance info and reaction times?
Ageing reduces number of neurons and nerve fibres, causing slower reaction times and impaired integration of balance info
How does ageing affect spinal cord input in a way that causes balance and coordination problems?
Ageing reduces proprioception and touch sensitivity in feet, so less accurate spinal cord input will be transmitted to cerebellar cortex, causing problems with balance and coordination
How does ageing affect muscle contractions?
Ageing reduces muscle mass and strength, so there are slower contractions
Give examples of accidents and environmental factors that can cause falls?
Cluttered rooms and corridors,
poorly fitting carpets,
uneven flooring,
slippery surfaces,
stairs,
inappropriate bed heights,
walking aids out of reach,
lack of appropriate supervision
What is the correlation between systemic diseases (eg. heart attacks, pneumonia) and incidence of falls?
Systemic (affect whole body) diseases such as acute illness, heart attacks, pneumonia are associated with higher incidence of falls
What are the 4 common causes of Transient Loss Of Consciousness (T-LOC) (uncomplicated fainting)?
cardiovascular syncope,
neurological seizures,
psychological conditions,
orthostatic/postural hypotension: low blood pressure that happens when standing after sitting or lying down
Give examples of parts of balance control system that can cause falls if they develop disease?
eyes, inner/middle ear, brain, nerve, muscle, joints, feet
Give 3 examples of chemicals that can increase incidence of falls?
Conventional medicines
Recreational drugs
Alcohol
What are the 2 situations in which a person has a falls assessment, and what are the results used for?
Screening suggests that person is at risk or they have symptoms eg. dizziness, big drop in bp after standing.
Results show risk of falling which is used to implement prevention strategies
According to PROFET study, Lancet, 1999, what finding was effective in preventing falls?
Combined medical clinic and OT home assessment
According to Campbell et al, BMJ, 1997-2001, what finding was effective in preventing falls?
Home-based individual exercise programme taught by physiotherapist/nurse, with patient expected to exercise 3 times per week
Give examples of ways to prevent falls?
Exercise to improve balance
Review medications for relevant side effects
Regular vision and hearing checks
Check home for hazards
Wear appropriate shoes
How does ageing affect the greatness of postural sway?
Increased postural sway
How does ageing affect normal posture?
Posture becomes flexed
Give 3 ways in which ageing affects gait?
Slower, shorter steps, less time on one leg
