7 balance

LECTURE 7

1. Therapeutic techniques to improve balance RIAZ AHMED PT

2. Balance deficits… one of the most common problems treated by physical therapists. are thought to be common after stroke, and they have been implicated in the poor recovery of activities of daily living (ADL) and mobility and an increased risk of falls .

3. What is balance?

4. Balance… “…the ability to maintain the body’s center of gravity over its base of support with minimal sway or maximal steadiness.” (Emery et.al, 2005) a complex process involving the reception and organization of sensory inputs and the planning & execution of movement to achieve a goal requiring upright posture

5. Balance… is the set of functions which maintains man’s upright during stance and locomotion by detecting and correcting displacement of the line of gravity beyond the BOS.

6. Terminologies… Postural control – involves controlling the body’s position in space for the dual purposes of stability and orientation. Postural orientation –The control of relative positions of the body parts by skeletal muscles with respect to gravity and each other.

7. Center of mass . The COM is a point that corresponds to the center of the total body mass and is the point where the body is in perfect equilibrium. It is determined by finding the weighted average of the COM of each body segment. Center of gravity . The COG refers to the vertical projection of the center of mass to the ground. In the anatomical position, the COG of most adult humans is located slightly anterior to the second sacral vertebra or approximately 55% of a person’s height. Terminologies…

8. Terminologies… Postural stability - The condition in which all the forces acting on the body are balanced such that the center of mass (COM)is with in the stability limits or boundaries of BOS Normal anterior/posterior sway – 12 degrees from most posterior-anterior position. Lateral sway - 16 degrees from side to side. If sway exceeds boundaries, compensation is employed to regain balance.

9. Terminologies… Static balance - the base of support (BOS) remains stationary and only the body center of mass (COM) moves. The balance task in this case is to maintain the COM within the BOS or the limit of stability (the maximal estimated sway angle of the COM). Maintaining a stable antigravity position while at rest such as when standing and sitting

10. Terminologies… Automatic postural reactions - maintaining balance in response to unexpected external perturbations, such as standing on a bus that suddenly accelerates forward.

11. Terminologies… Dynamic balance - Maintaining balance when a person is moving from point A to point B, where both the BOS and COM are moving, and the COM is never kept within the BOS. is stabilizing the body when the support surface is moving or when the body is moving on a stable surface such as sit-to-stand transfers or walking

12. Terminologies… Reactive control - in response to external forces (perturbation). Proactive control – in anticipation of internal forces imposed on the body’s own movements.

13. The Systems Model

14. Systems Model… Balance control is very complex and involves many different underlying systems. Postural control results from a set of interacting systems that work cooperatively to control both orientation and stability of the body.

15. BALANCE Anticipatory Mechanisms (internal) Proactive Mechanisms (external) Reactive Mechanisms Sensory Systems Body Schema Neuro-muscular Synergies Musculo-skeletal Components

16. Musculoskeletal components Joint range of motion Spinal flexibility Muscle properties Biomechanical relationships among linked body segments

17. Neural components Motor processes (neuromuscular response synergies) Sensory processes ( visual, vestibular, and somatosensory systems) Higher-level integrative processes Mapping sensation to action Ensuring anticipatory and adaptive aspects of postural control

18. Adaptive vs. Anticipatory Adaptive postural control Involves modifying sensory and motor systems in response to changing task and environmental demands Anticipatory postural control Involves preparing the sensory and motor systems for postural demands based on previous experience and learning

19. Motor Mechanisms for Postural Control

20. Factors that contribute to stability… Body alignment Muscle tone Postural tone

21. Body alignment… Minimize the effect of gravitational forces, which tend to pull us off center The ideal alignment in stance allows the body to be maintained in equilibrium with the least expenditure of internal energy.

22. Body alignment appropriate to quiet standing and sitting Standing alignment Head balanced on level shoulders Upper body erect, shoulders over hips Hips in front of ankles Feet a few cm (10 cm) apart Sitting alignment Head balanced on level shoulders Upper body erect Shoulders over hips Feet and knees a few cm apart

23. Muscle tone… The force with which a muscle resists being lengthened (Basmajian and De Luca, 1985) Keeps the body from collapsing in response to the pull of gravity

24. Postural tone… Increased level of activity in antigravity muscles Activation of antigravity muscles during quiet stance. Muscles that are tonically active during quiet stance: gastrocsoleus, tibialis anterior, gluteus medius, TFL, iliopsoas, and erector spinae

25. Motor strategies during Perturbed Stance Ankle strategy Hip strategy Stepping strategy Weight shift strategy Suspension strategy

26. Ankle strategy… Used when displacements are small. Displaces COG by rotation about the ankle joint. Posterior displacement of COG – Dorsiflexion at ankle, contraction of anterior tibialis, quadriceps, abdominals. Anterior COG displacement – Plantar flexion at ankle, contraction of gastrocnemius, hamstring, trunk extensors.

27. Hip strategy… Employed when ankle motion is limited, displacement is greater, when standing on unstable surface that disallows ankle strategy. Preferred when perturbation is rapid and near limits of stability. Post. Displacement COG – Backward sway, activation of hamstring and paraspinals. Ant Displacement COG – Forward sway, activation of abdominal and quadricep muscles.

28. Stepping strategy… If displacement is large enough, a forward or backward step is used to regain postural control

29. Weight shift strategy The movement strategy utilized to control mediolateral perturbations involves shifting the body weight laterally from one leg to other. Hips are the key control points of weight shift strategy. they move the COM in a lateral plane primarily through activation of hip abductor and adductor muscles.

30. Suspension strategy This strategy is observed during balance tasks when a person quickly lowers his or her body COM by flexing the knees, causing associated flexion of the ankles and hips.

31. Sensory Mechanisms Related to Postural Control

32. Triad of Balance

33. Sensory processes… The maintenance of balance is based on an intrinsic cooperation between the Vestibular system Proprioceptive Vision Postural control does not only depends on the integrity of the systems but also on the sensory integration with in the CNS, visual and spatial perception, effective muscle strength and joint flexibility

34. Visual inputs… Provides information regarding: (1) The position of the head relative to the environment; (2) The orientation of the head to maintain level gaze; (3) The direction and speed of head movements because as your head moves, surrounding objects move in the opposite direction. Provide a reference for verticality Visual stimuli can be used to improve a person’s stability when proprioceptive or vestibular inputs are unreliable by fixating the gaze on an object.

35. Visual inputs are important source of information for postural control, but are they absolutely necessary?

36. No… Since most individuals can keep their balance when vision is occluded In addition, visual inputs are not always an accurate source of orientation information about self-motion . Visual system has difficulty distinguishing between object motion, referred to as exocentric motion , and self-motion, referred to as egocentric motion .

37. Somatosensory inputs… Provides the CNS with position and motion information about the body with reference to supporting surfaces Report information about the relationship of body segments to one another Receptors: muscle spindles, Golgi tendon organs, joint receptors, and cutaneous mechanoreceptors

38. Vestibular inputs… A powerful source of information for postural control Provides the CNS with information about the position and movement of the head with respect to gravity and inertial forces, providing a gravitoinertial frame of reference. Distinguish exocentric and egocentric motions

39. Vestibular receptors Semicircular canal Sense angular acceleration of the head Sensitive to fast head movements ( those that occur during gait or imbalance such as slips, trips, and stumbles) Otolith organs Signal linear position and acceleration Source of information about head position with respect to gravity Respond to slow head movements (those that occur during postural sway)

40. Sensory organization… Vestibular, visual, and somatosensory inputs are normally combined seamlessly to produce our sense of orientation and movement. Incoming sensory information is integrated and processed in the cerebellum, basal ganglia, and supplementary motor area.

41. Sensory organization… Somatosensory information has the fastest processing time for rapid responses, followed by visual and vestibular inputs When sensory inputs from one system are inaccurate the CNS must suppress the inaccurate input and select and combine the appropriate sensory inputs from the other two systems.

42. The Motor Control Model

43. Causes of balance impairments Injury to or diseases of the structures (e.g. eyes, inner ear, peripheral receptors, spinal cord, cerebellum, basal ganglia, cerebrum) Damage to Proprioceptors Injury to or pathology of hip, knee, ankle, and back have been associated with increases postural sway and decreased balance Lesions produced by tumor , CVA, or other insults that often produced visual field losses

44. Following a stroke… Patients with muscle weakness and poor control lack effective anticipatory, ongoing, and reactive postural adjustments and therefore experience difficulty in: Supporting the body mass over the paretic lower limb Voluntarily moving the body mass from one lower limb to another Responding rapidly to predicted and unpredicted threats to balance

45. Spatiotemporal adaptations Changing the base of support Restricting movement of body mass Using hands for support

46. Changing the base of support Wide BOS Shuffling feet with inappropriate stepping Shifting on the stronger leg

47. Restricting movement of body mass Stiffening the body with altered segmental alignment Moving slowly Changing segmental alignment to avoid large shifts in COG standing reaching forward - flexing at hips instead of dorsiflexing ankles standing reaching sideways - flexing trunk sideways instead of moving body laterally at hips and feet sitting reaching sideways - flexing forward instead of to the side in standing - not taking a step when necessary.

48. Using the hands for support holding on to support grabbing

49. Assesment & Guidelines for training balance

50. Assesment

51. Assessing Static Balance Using Indirect Measures Romberg tests: measure static balance while standing with eyes open and eyes closed Unipedal stance test: timed one-leg stance test that provides simple measure of static balance; two conditions: eyes open, eyes closed Clinical test of sensory integration of balance: evaluates the contributions of the visual, proprioception, and vestibular sensory systems to balance

52. Assessing Dynamic Balance With Indirect Measures Functional reach tests: measure maximum distance one can reach beyond an arm’s length without losing balance or moving the feet Timed up and go tests: assess dynamic balance and agility of older adults Star excursion balance test: provides a significant challenge to athletes and physically active individuals

53. Functional Reach test

54. Figure 12.2

55. Figure 12.3 a

56. Figure 12.3 b

57. Sensory organization test The clinical test of sensory integration on balance test (CTSIB) also called as foam and dome test.

58. Balance Assesment

59. Guidelines… Balance cannot be trained in isolation from the actions which must be relearned. In training walking, standing up and sitting down, reaching and manipulation… postural adjustments are also trained, since acquiring skill involves in large part the fine tuning of postural and balance control.

60. Guidelines… Postural adjustments are specific to each action and the conditions under which it occurs. It cannot be assumed that practice of one action will transfer automatically into improved performance in another.

61. Guidelines… Progressive complexity is added by increasing the difficulty under which goals must be achieved, keeping in mind the various complex situations in which the patients will find themselves in the environment in which they live, both inside and outside their homes, and the precarious nature of balance.

62. Guidelines… As control over balance and confidence improves, tasks are introduced which require a stepping response , and responses to external constraints such as catching a thrown object and standing on a moving support surface

63. Guidelines… Use a gait belt any time the patient practices exercises or activities that challenge or destabilize balance. Stand slightly behind and to the side of the patient with one arm holding or near the gait belt and the other arm on or near the top of the shoulder (on the trunk, not the arm). Perform exercises near a railing or in parallel bars to allow patient to grab when necessary. Do not perform exercises near sharp edges of equipment or objects.

64. Guidelines… Have one person in front and one behind when working with patients at high risk of falling or during activities that pose a high risk of injury. Check equipment to ensure that it is operating correctly. Guard patient when getting on and off equipment (such as treadmills and stationary bikes). Ensure that the floor is clean and free of debris.

65. Techniques to improve balance

66. Mode A variety of mode can be used to treat balance impairment Begin with weight shifts on a stable surface Gradually increase sway Increase surface challenges (mini-tramp, etc.)

67. Mode Rehabilitation balls ,foam rollers ,foam surfaces are often used to Provide uneven or unstable surface for exercise Sitting balance ,trunk stability, and weight distribution can be trained on a chair, table, or therapeutic ball Pool is an ideal palace for training balance

68. Postural training Awareness of posture and the position of the body in space is fundamental to balance training Begin in supine or seated position Over sessions, use a variety of arm positions, unstable surfaces, single leg stances, etc . Training both Static posture & Dynamic posture Mirrors can provide postural feedback –Visual feedback

69. Movement Adding movement patterns to acquired stable static postures increases balance challenge. Add ant./post. sway to increase stability limits Trunk rotations and altered head positions alter vestibular input. Stepping back/forward assists in re-stabilization exercises.

70. Progression… From simple to complex involves BOS – Advance from wide to narrow base Posture – Stable to unstable posture (sway) Visual – Closing of the eyes COG – Greater disruption to elicit hip or stepping strategy Progress to more dynamic activities, unstable surfaces, and complex movement patterns Frequency,intensity,and duration

71. Specific techniques…

72. Bobath Normal postural activity forms necessary background for normal movement and for functional skills Flaccid stage – balance exercises in sitting Stage of spasticity – practice symmetrical weight bearing in standing, weight shifting, bending of knees and hips

73. PNF techniques For stability Combination of isotonics Stabilizing reversals Rhythmic stabilization

74. Motor Relearning Program Analysis of task Individual Task Environment Practice of missing components Strategy training Impairment and strategy level Practice of whole task Functional level Transference of learning

75. Static balance Vary postures Vary support surface Incorporate external loads

76. Dynamic balance Moving support surfaces Move head, trunk, arms, legs Transitional and locomotor activities

77. Anticipatory ( feedforward ) Reaching Catching Kicking Lifting Obstacle course

78. Reactive (feedback) Standing sway Ankle strategy Hip strategy Stepping strategy Perturbations

79. Sensory organization Reduce visual inputs Reduce somatosensory cues

80. Sitting balance… acute stage post-stroke Head and trunk movements Reaching actions To progress: Increasing distance to be reached Varying speed Reducing thigh support Increasing object weight and size to involve both upper limbs Adding an external timing constraint such as catching or bouncing a ball

81. Standing balance… Head and body movements Reaching actions Single limb support Sideways walking Picking up objects

82. Pediatrics… The following main aspects should be developed: Antigravity support or weight bearing on the feet Postural fixation of the head on the trunk and on the pelvis in the vertical Control of anteroposterior weight shift of the child’s COG Control of lateral sway from one foot to the other. Tilt reactions in standing Saving from falling (strategies)

83. Pediatrics… Training should check: Equal distribution of weight on each foot Correction of abnormal postures Building up of the child’s stability by decreasing support Delay training in standing and walking if the child is not ready Weight shift leading to stepping Training lateral sway Training on different surfaces

84. Assignment: Read Kisner’s Chapter on Techniques to improve balance.

85. References Adler SA, Beckers D, & Buck M (1993). PNF in practice. Berlin, Springer-Verlag. Carr JH & Shepherd RB (2003). Stroke rehabilitation: Guidelines for exercise and training to optimize motor skill. Edinburgh, Butterworth-Heinemann. Davies PM (1985). Steps to follow: A guide to the treatment of adult hemiplegia. Berlin, Springer-Verlag. Kisner C & Colby LA (2007). Therapeutic exercise: Foundations and techniques (5 th ed). Philadelphia, F. A. Davis Company. Levitt S (2004). Treatment of cerebral palsy and motor delay (4 th ed). Singapore, McGraw-Hill Inc. Sawner K & LaVigne J (1992). Brunnstrom’s Movement Therapy in hemiplegia: A Neurophysiological Approach (2 nd ed). Philadelphia, J.B. Lippincott Company. Shumway-Cook, A & Woollacott, M. (2001). Motor control: Theory and practical applications (2 nd ed.). Philadelphia: Lippincott Williams & Wilkins.