Balance Flashcards
1
Q
What is the center of mass (CoM)?
A
Point at which distribution of mass is equal in all directions
2
Q
CoM is (dependent/independent) of gravity.
A
Independent of gravity
3
Q
T/F CoM changes with body position.
A
True
4
Q
Where do you find the CoM on body height? Compared to sacrum?
A
2/3 of body height above BOS, slightly anterior to sacrum (slightly above belly button)
5
Q
What is the center of gravity (CoG)?
A
Vertical projection of CoM
6
Q
CoG is (dependent/independent) of gravity.
A
Gravity dependent (take string from top of head down to ankle)
7
Q
Describe the line of CoG through upright body:
A
Ankle/knee joints - anterior Hip joint - at or posterior Trunk - midline GH joint - anterior External auditory meatus - through
8
Q
If you have weakness in legs and can’t support body against gravity, which way will you collapse?
A
Into direction of gravity
9
Q
What is base of support (BoS)?
A
Area beneath a person that includes every point of contact that the person makes with the supporting surface (foot
10
Q
What is balance?
A
Control of CoM over BoS
11
Q
What are 3 aspects of balance?
A
- Posture control
- Postural stability
- Postural orientation
12
Q
What is postural control?
A
control body in space in and out of our base of support
13
Q
What is postural stability?
A
control CoM and Cog over BoS in varying sensory environments
ex: tightrope walking
14
Q
What is postural orientation?
A
maintain position in space with respect with gravity
15
Q
What is sensorimotor integration in postural control?
A
peripheral structures to brain (afferent feedback)
16
Q
CNS processing is dependent on input from what 3 things?
A
- Vision
- Vestibular
- Somatosensory
17
Q
On firm/stable surface what % of:
Somatosensory -
Vestibular -
visual -
A
Somatosensory - 70%
Vestibular - 20%
visual - 10%
18
Q
On compliant surface what % of:
Somatosensory -
Vestibular -
visual -
A
Somatosensory - 10%
Vestibular - 60% (unusual feedback so brain relies on vestibular more)
visual - 30%
19
Q
As we age, we become more reliant on what input to CNS?
A
More visually reliant
20
Q
What input is the dominant sense for upright postural control?
A
Somatosensory Input - Most active in triggering automatic postural responses in almost all cases
21
Q
Receptors where will provide information about muscle length, stretch, tension and contraction as well as pressure and joint position?
A
Receptors (Pressure/light touch, proprioception) located in joints, ligaments, muscles, skin
22
Q
Central (foveal) vision gives input about what type of oreination?
A
- Environmental orientation
- Perceptions of vertically and object motion
- Identification of hazards and opportunities
23
Q
Central (foveal) vision receives (subconscious/conscious) recognition.
A
Conscious
24
Q
Peripheral (ambient) vision detects motion of what?
A
- Detects motion of self in relation to environment
- Head movements, postural sway
25
Peripheral (ambient) vision receives (subconscious/conscious) recognition.
Subconscious
26
Visual input assists with what type of postural control in changing environments?
Feedforward (anticipatory) postural control in changing environments
27
Vestibular input provides what type of information to CNS? Using what structures?
- information to CNS about position and motion of the head
| - Semicircular Canals, Otoliths
28
Vestibular input is unique in its ability to distinguish ___ motion from ___ motion
Unique in its ability to distinguish self-motion from environmental motion
29
Central sensory structures function first to compare available inputs between ____ and then between ____
between two sides and then between the three sensory systems
30
Whens changes to the environment occur, what will occur with the sensory systems?
- the relative availability, accuracy, and usefulness of information from the three sensory systems may also change
- Available, accurate, and useful information is “upweighted,” whereas unavailable, inaccurate, or less-useful information is “downweighted.”
31
Describe changes in sensory input when walking at night:
Vision is down weighted
| Somatosensory and vestibular information upweighted
32
Describe changes in sensory input when walking on beach
Vestibular upweighted
33
What are the 3 different balance mechanisms?
1. Steady state
2. Anticipatory postural control
3. Reactive postural control
34
What is steady state balance?
quiet balance – always working on balance but not a lot of work
35
What is anticipatory postural control?
activating balance in advance based on prior experiences
36
What is reactive postural responses?
recovery from unplanned perturbation to balance resulting in displacement of CoG or moving the BOS
37
What is an example of anticipatory postural control?
catching a ball
38
What type of system and CNS control for anticipatory postural control?
- Feedforward system – relies on prior experience (motor learning/cerebellum)
- Cerebellar control
39
What UE/LE muscles react the quickest to anticipatory postural control?
Upper Extremities: Biceps
| Lower Extremities: Gastrocnemius
40
T/F Postural sway is normal, gentle, automatic and involuntary A&P oscillations
True
41
Postural sway occurs at what body part during quiet standing? Quiet sitting?
- Around ankle during quiet standing
| - Around hip during quiet, unsupported sitting
42
What are the limits of stability? What is normal degree?
Points at which CoM approaches the limits of the BOS during postural sway or leaning
normal = 8 degrees in all directions
43
What type of system is reactive postural responses?
feedback (reacting quickly)
44
Reactive postural responses are dependent on what?
Fast sensory and motor responses (visual, proprioception, vestibular, motor control and muscle grading)
45
What are the 3 strategies of reactive postural responses?
1. Ankle
2. Hip
3. Stepping
46
When are ankle strategies used? What type of perturbations? Direction?
1. Quiet standing
2. Counteract small perturbations
3. Distal to proximal, head stays in line with hips
47
What type of perturbations are hip strategies used for? Primary strategy for what kind of control? Direction?
- Counteract larger perturbations
- Primary strategy for mediolateral control
- Proximal to distal, no alignment of head and hips
- Not as efficient
48
When are stepping strategies used?
- When ankle and hip strategies fail
- Ultimately increases base of support
- Can reach out with hands
49
T/F Normal balance can be combination of all 3 types of reactive postural responses.
True
50
T/F Ankle PF and DF strength are independent predictors of functional performance
True
51
T/F Plantarflexion strength of big toe affected balance and function in older adults
True
52
Weakness of what two motions was associated with increased likelihood of employing a multi-step strategy to recover from balance perturbations?
hip and knee extensors
53
T/F Exercise has shown to have a protective effect on fall risk in older adults
True
54
```
Sitting balance:
Somatosensory input -
Stability -
Direction of control stability -
Anticipatory Postural control -
Reactionary strategies -
```
Somatosensory input - Thighs, buttocks, and feet
Stability - less degrees of freedom (3)
Direction of control stability - A/P most stable, LOB tends to primarily occur laterally
Anticipatory Postural control - Gastrocnemius*, quadriceps, glutes
Reactionary strategies - reaching
55
```
Standing balance:
Somatosensory input -
Stability -
Direction of control stability -
Anticipatory Postural control -
Reactionary strategies -
```
Somatosensory input - ankle/foot
Stability - more degrees of freedom (6)
Direction of control stability - Lateral more stable than A/P
Anticipatory Postural control - Trunk extensors
Reactionary strategies - ankle, hip, step
56
What is the goal during gait?
controlled forward transference of CoM
57
What % of BoS is DLS during gait?
40%
58
What % of BoS is SLS during gait?
60%
59
T/F Entirety of soles of both feet are never in contact with floor at same time
True
60
T/F Anticipatory postural adjustments were two times longer for unilateral stance conditions than bipedal conditions
True
61
What is dual task control?
- Multitasking and filtering out distractions while maintaining balance
- More functional
62
T/F Falls are the most common cause of traumatic brain injuries (TBI)
True
63
What are intrinsic risk factors for fall risk? (6)
1. Age
2. Impaired balance
3. Prior history of falls
4. Fear of falling
5. Comorbidities/Disease State (Neuropathic, Musculoskeletal, Visual, Cognitive, Cardiovascular)
6. Medication side effects (drowsy, fatigue, hypotension)
64
What are extrinsic risk factors for fall risk? (7)
1. Type of surface
2. Slippery surface
3. Obstacles, stairs, curbs
4. Poor lighting or sudden changes in lighting
5. Footwear
6. Poorly fitted assistive devices and/or orthotics
7. Recreational drugs, alcohol
65
Fall stats for patients >65:
1. 1 in 4 Americans fall each year
2. Falls are the leading cause of fatal injury and the most common cause of nonfatal trauma-related hospital admissions among older adults
3. Community-dwelling incidence 30-40%, with injury rate 10 to 15%
4. Fall-related injuries lead to to 15% re-hospitalizations in first month post-discharge
66
T/F Aging directly causes bad balance
False, aging negatively impacts crucial systems involved in our balance, which leads to higher risk for falls (negative sequelae)
67
With aging, limits of stability tend to (decrease/increase)
Decrease
68
With aging, see (smaller/larger) and more (delayed/quick) anticipatory postural adjustments
larger
| delayed
69
T/F Higher levels of physical fitness were correlated with better anticipatory responses (strengthening, aerobic conditioning)
True
70
T/F Fear of falling found to decrease anticipatory postural adjustment durations.
False, increase
71
T/F Direct correlation between muscle fatigue and slowed reactive postural responses in older adults.
True
72
Increased dominance of (ankle/hip) strategy, even with smaller CoM displacements with aging.
Hip
73
Describe the visual changes that occur with aging: (7)
1. Presbyopia (age-related farsightedness)
2. Glare sensitivity
3. Reduced dark adaptation
4. Difficulty shifting focus between near/far
5. Slower visual reaction time
6. Difficulty distinguishing color
7. Loss of peripheral vision
74
Common visual pathologies seen with aging:
1. Cataracts
2. glaucoma
3 macular degeneration
4. diabetic retinopathy
75
What functional implications of visual changes with aging? (3)
1. Higher fall risks at night or in reduced lighting
2. At risk to trip over objects due to peripheral loss
3. Slower reaction time -> reduced reactionary strategies for balance
76
What vestibular changes seen with again? (5)
1. Loss of hair cells in SCC and otoliths
2. Calcification of otolithic membranes
3. Microvascular ischemia
4. Reduction of vestibular and cerebellar neurons and nuclei
5. Reduced effectiveness of VOR
77
What functional implications of vestibular changes with aging? (4)
1. Less capacity for detection of rotation and gravity-related positions
2. Reduced gaze stabilization with head movements
3. Increased postural sway
4. Sensory substitutions can mask deficit more effectively than with other impaired systems
78
What Neuromuscular/Musculoskeletal Changes seen with aging? (7)
1. Decrease in # of type I and II fibers (II>I)
2. Decrease in # of MUs as well as maximal voluntary muscle activation
3. Muscle performance (strength, power, endurance) decreases 3% every year after age 60
4. Decrease in peak anaerobic muscle power
5. Increase in agonist/antagonist co-activation during volitional movement
6. Increased muscle connective tissue -> decreased flexibility
7. Increased risks of osteoporosis
79
Functional implications of Neuromuscular/Musculoskeletal Changes seen with aging? (4)
1. Reductions in strength, power and muscle endurance have all been tied to balance deficits
2. High prevalence of OP results in more risk of fracture when falls occurs
3. Postural changes lead to changes in COM/COG/BOS
4. Greater axial stiffness and reduced flexibility
80
What cognitive changes seen with aging? (5)
1. Conceptual reasoning, memory, and processing speed decrease with time
2. Decreased use of strategies to improve learning and memory
3. Reduced selective and divided attention
4. Gradual reduction in visual constructional skills (assembly of pictures)
5. Research has shown that concept formation, abstraction, and mental flexibility decline with age, especially after age 70
81
Functional implications of cognitive changes seen with aging? (2)
1. DUAL TASK
| 2. Carry over (memory diminish – decrease carry over for older adults)
82
What 4 things do we take into account when determining if patient is off balance?
1. Observation
2. CLinical hx taking
3. Subjective outcome measures (questionnaires)
4. Objective Outcome measures
83
What do we observe to determine if patient is off balance?
1. Postural alignment, weight distribution (leaning)
| 2. Functional task analysis (watch movement/walking/ stairs)
84
What 3 things of importance when looking for good clinical objective outcome measures?
1. Cut-off scores (specific type of risk with certain score)
2. Minimum Detectable Change (MCD) – if number met it means actual improvement, not just random
3. Meaningful Clinically Important Difference (MCID) – amount of change we will see in functional task
85
What is the Activities-Specific Balance Confidence Scale (ABC)?
- 16-item subjective questionnaire (0-100 score)
- Measure of balance confidence in performing various activities without losing balance or experiencing a sense of unsteadiness
86
The ABC evaluates what balance task as well as what type of mobility?
Evaluates vestibular and non-vestibular balance tasks as well as functional mobility
87
What is the Tinetti Falls Efficacy scale?
- 10-item subjective questionnaire
- Assesses perception of balance and stability during activities of daily living as well as non-vestibular balance tasks, functional mobility, life participation, and self-efficacy
88
What are the cutoff scores for the Tinetti Falls Efficacy scale?
>80 increased risk of falling
| >70 indicates fear of falling
89
What type of task do you need good limits of stability (postural sway)? What outcome measures?
- Reaching tasks
| - Outcome Measures: Functional Reach Test, Multidirectional Reach Test
90
What type of task do you need good Anticipatory Postural Control (activating balance in advance)? What outcome measures?
- Activities that require trunk rotation (Reaching, twisting, stepping, kicking, punching)
- Outcome Measures: 5TSTS, BBS, Mini BESTest, 4 Square Step Test
91
What type of task do you need good Reactive Postural Responses (CoM/CoG out of BoS)? What outcome measures?
- Activities that require a patient to respond quickly (Start/stop activities)
- Outcome Measures: Push/Pull Test, Mini BESTest, DGI/FGA, Tinetti
92
What tests used to examine sensorimotor integration? (3)
1. Romberg Test – tendon eyes open/closed
2. Sensory Organization Test (SOT)
3. Clinical Test for Sensory Interaction in Balance (CTSIB)
“Foam and Dome Test”
93
What are the APTA EDGE 6 core outcome measures?
1. Berg Balance Scale
2. Functional Gait Assessment
3. Activities-Specific Balance Confidence Scale (subjective)
4. 10 Meter Walk Test
5. 6 Minute Walk Test
6. 5 Times Sit to Stand
94
Balance considerations for anticipatory postural control?
1. Feedforward system that closely coincides with motor control and accurate muscle grading
2. Principles of Neuroplasticity are crucial with training this aspect of balance
- Especially: repetition, specificity matters, and transference
95
Balance considerations for reactive postural responses?
1. What balance strategies do you observe with min, mod, max perturbations? (All 3 should be observed!)
2. Does the patient appear to have WNL limits of stability?
3. What impairments are leading to the lack of, or inappropriate use of each reactive strategy?
4. Cognitive considerations – can the patient be educated on these strategies?
