Functional Decrements Among Elderly

7/30/2019 Functional Decrements Among Elderly

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Why Functional Decrements are

Reality among Elderly?

Amitesh Narayan



Force Control and Regulation

• Force control is an elementary

component of movement production

because smooth and accuratemovements require efficient

modulation of force outputs.




• Changes in the regulation of force outputs lead to

decrements in the initiation and control of

movements.

• Olders compared to young adults have decreasedforce outputs and inefficient force regulation making

it difficult to initiate and execute movements quickly

and accurately across a variety of tasks (Brown, 1996; Campbell, McComas,

and Petito, 1973; Clamann, 1993; Cooke et al., 1989; Darling et al., 1989; Davies and White, 1983; Doherty, Vandervoort, and Brown,1993; Galganski et al., 1993; Izquierdo, Aguado, Gonzalez, Lopez, and Hakkinen, 1999; Larsson and Karlsson, 1978; Milner-Brown,

Stein, and Yemm, 1973; Milner, Cloutier, Leger, and Franklin, 1995; Roos, Rice, Connelly, and Vandervoort, 1999; Singh et al., 1999;

Stelmach, Teasdale, Phillips, and Worringham, 1989).




• Stelmach and colleagues (1989), using an isometric

task , demonstrated that older adults have reduced

range of force production and higher force output

variability compared with young adults.

• Rate of force production slows down substantially

{20 ms longer to achieve a force level 45 percent of

their maximum (15 N)}.




• Ng and Kent-Braun (1999) documented

similar findings with older adults.

• They reported 60-N lower peak force output in

older adults compared to young adults and a

20-ms-longer time for force production.




• Elderly produces multiple bursts of force in tasks_ to

achieve targeted force levels (approaching maximum).Kinoshita and Francis, 1996; Brown, 1996; Galganski et al., 1993.

• In contrast to above, young adults_ produces single

burst to the targeted force level.



Functional Implications

• All these changes are small and happenings over short

periods.

• These changes may be a result of_ motor unit

reorganization and muscle composition changes

• But , they do suggest a reason why control andcoordination change with advanced age.



Functional Implications_ Examples

• Changes in force regulation and control have largeimplications for most functional tasks.

• Turning a door knob or

•

Picking up a glass of liquid.• Tying shoe lace

• Eating with spoon

• Tying Button of shirt

• Stirring spoon in cup to mix sugar

• Climbing steps

• Playing with grand children ball game



Coordination_ Definition

• Coordination is the ability to control a

number of movement segments or body

parts in a refined manner resulting in a

well-timed motor output.



Coordination_ With advancing age

• Ability to control multiple movement components at

any particular time becomes increasingly difficult

across variety of movements.

• E.G: Aiming, Reaching and Grasping, Drawing,

Handwriting, and Bimanual coordination tasks(Bennett and Castiello, 1994; Carnahan et al., 1998; Teulings and Stelmach, 1993; Greene and Williams, 1996; Swinnen et al., 1998;

Wishart et al., 2000; Ketcham et al., 2001).




• In reach-to-grasp tasks, components involved are:

a. Transport, and

b. Grasp components

Both must be coordinated both spatially and

temporally.

• Researchers found that older adults exhibit unstable

temporal coupling between these components (Bennett and

Castiello, 1994; Carnahan et al., 1998).




• Conversely, tasks like drawing or handwriting require

subjects to control multiple joints in a linked segment

(require more regulation at fast movement speeds) (Teulings and

Stelmach, 1993; Ketcham et al., 2001).

•Ketcham and colleagues (2001) found that in a cyclical drawingtask older adults begin to distort their movements at 2.0

Hz (two cycles per second) compared with young adults

who begin distortions at 2.5 Hz.

• Reason_ older adults are unable to accurately control the

passive properties of linked segments, resulting in slower and

more variable movements.




• Seidler and colleagues (2002) found that aiming movements away

from the body (that required shoulder and elbow

participation), became less smooth and decoupled as

shoulder contribution increased.

• Young adults tended to increase activity of opposing

muscles as shoulder involvement increases, while

older adults coactivates these muscles at high levels

during single joint elbow movements and reduced

coactivation as shoulder involvement increases.



Bimanual coordination

• In these tasks subjects are asked to produce samemovement with left and right limbs.

• These movements are typically either

a. In_phase, where two limbs move in the same anatomicaldirection (homologous muscles activated together), or

b. Antiphase, where two limbs move in the same absolutedirection (homologous muscles activated at 180-degree

offset or opposite of each other).



Bimanual coordination_ With advancing age

• Older adults tend to have difficulty maintaining more

complicated antiphase movements as movement

speeds increase (Swinnen et al., 1998; Greene and Williams, 1996; Wishart et al., 2000).

• Older adults are less accurate at movement speeds of

1.5 and 2.0 Hz compared with young adults, with

absolute errors on the order of 20 degrees of relative

phase offset.




• Older adults have increased difficulty controlling and

regulating multiple segments to produce smooth

motor outputs.




• Coordination is a part of most tasks of daily livingand therefore it is essential to understand breakdowns

in control and regulation.



Proprioception_ With advancing age

• Reduced ability in older adults to accurately detect

movement or localize a body segment position makes it

difficult to produce rapid, well-coordinated movements.

• Major functional implications for older adults in a

variety of tasks of daily living,

a. Sitting in a chairb. Reaching for an object.

• Older adults tends to underestimate their joint angle.



Muscle Activation Patterns_ Normal

•

For most movements, the underlying muscle activation patternsare organized in a triphasic pattern consisting of

a. 2 bursts of agonist muscle activity separated by,

b. 1 single burst of antagonistic muscle activity

Berardelli et al., 1996.

• This triphasic pattern of muscle activity produces a smooth

trajectory of a body segment from one position to another,

a. with the first agonist burst initiating the movement, overcominginertial forces; then

b. the subsequent two bursts decelerate or brake the movement of

the limb to the desired position Berardelli et al., 1996; Brown, 1996; Buneo, Soechting, and Flanders,

1994; Darling et al., 1989.



Muscle Activation Patterns_ Elderly

• Research indicates that older adults do not tightly couple the

triphasic agonist-antagonist-agonist activation pattern as

young adults do.

• Timing of triphasic muscle activity is highly variable, without a

clear alternating pattern of agonist-antagonist activation.

• Antagonist burst is not well defined and occurs abnormally earlyDarling et al., 1989.

• Consequently, older adults often produce movements that have

prolonged deceleration patterns or periods of braking of the

movement Berardelli et al., 1996; Brown, 1996; Seidler-Dobrin et al., 1998; Darling et al., 1989.



Muscle Composition and Muscle Activation

Patterns_ with advancing age

• Number and size of muscle fibers decrease in older

adults

• Most substantial decrease_ happens in fast-twitchfibers (which can be activated quickly for large force

outputs, but are unable to sustain force output for

long periods of time) Yamada, Masuda, and Okada, 2002.



Muscle Composition and Muscle Activation

Patterns_ with advancing age

• Among elderly type II (fast-twitch) muscle fibers decrease by

approximately 40 % , whereas slow-twitch muscle fibers stay

relatively stable across the life span Aniansson, Hedberg, Henning, and Grimby, 1986; Lexell,

1993; Singh et al., 1999; Yamada et al., 2002.

• In elderly, activation of muscle is more bursty and less

smooth compare to young adults, causing force outputs of

large incremental steps Brown, 1972; McComas, Fawcett, Campbell, and Sica, 1971; Roos et al., 1997, 1999.

• Contractile speed of muscles in older adults is slower than in

young adults, which also influences the ability to ramp forces

in any given muscle Davies and White, 1983; Larsson, Li, and Frontera, 1997; Ng and Kent-Braun, 1999; Roos

et al., 1997.



Joint Flexibility Changes

• With advanced age, the length of muscles around the

joints is reduced due to reduced flexibility of joint

structures (changes in hydration and microstructure of

collagen within the joint) Nonaka et al., 2002; Wachtel, Maroudas, and Schneiderman, 1995; Bailey

and Mansell, 1997; Wachtel et al.,1995.

• Loss of cartilage surface and chemical characteristic

changes_ Osteoarthritis development Laver-Rubich and Silbermann, 1985;

Beaupre, Stevens, and Carter, 2000; Bernick and Cailliet, 1982.



Joint Flexibility Changes_ Functional Implications

• Decreased flexibility has implications for tasks of

daily living

a. Putting on socks or stockings,

b. Safely pulling out into traffic,

c. Picking up a dropped object,Gehlsen and Whaley, 1990; Nonaka et al., 2002; Shepard et al., 1990; Spirduso, 1995).



References• Bennett, K.M., and Castiello, U. (1994). Reach to grasp: Changes with age. Journal of Gerontology,

49(B1), P1-P7.

• Berardelli, A., Hallett, M., Rothwell, J.C., Agostino, R., Manfredi, M., Thompson, P.D., and

Marsden, C.D. (1996). Single-joint rapid arm movements in normal subjects and in patients with

motor disorders. Brain, 119, 661-674.

• Buneo, C.A., Soechting, J.F., and Flanders, M. (1994). Muscle activation patterns for reaching: The

representation of distance and time. Journal of Neurophysiology, 71(4), 1546-1558.

• Campbell, M.J., McComas, A.J., and Petito, F. (1973). Physiological changes in ageing muscles.

Journal of Neurology, Neurosurgery and Psychiatry, 36(2), 174-182.

• Carnahan, H., Vandervoort, A.A., and Swanson, L.R. (1998). The influence of aging and target

motion on the control of prehension. Experimental Aging Research, 24(3), 289-306.

• Cerella, J. (1985). Information processing rates in the elderly. Psychological Bulletin, 98(1), 67-83.

• Clamann, H.P. (1993). Motor unit recruitment and the gradation of muscle force. Physical Therapy,

73(12), 830-483.



References• Contreras-Vidal, J.L., Teulings, H.L., and Stelmach, G.E. (1998). Elderly subjects are

impaired in spatial coordination in fine motor control. Acta Psychologica, 100(1-2), 25-35.

• Cooke, J.D., Brown, S.H., and Cunningham, D.A. (1989). Kinematics of arm movements inelderly humans. Neurobiology of Aging, 10(2), 159-65.

• Darling, W.G., Cooke, J.D., and Brown, S.H. (1989). Control of simple arm movements inelderly humans. Neurobiology of Aging, 10(2), 149-157.

• Davies, C.T., and White, M.J. (1983). Contractile properties of elderly human triceps surae.Gerontology, 29(1), 19-25.

• Doherty, T.J., Vandervoort, A.A., and Brown, W.F. (1993). Effects of ageing on the motor unit:A brief review. Canadian Journal of Applied Physiology, 18(4), 331-358.

•

Drowatzky, K.L., and Drowatzky, J.N. (1999). Physical training programs for the elderly.Clinical Kinesiology, 53(3), 52-62.

• Gauchard, G.C., Jeandel, C., Tessier, A., and Perrin, P.P. (1999). Beneficial effect of proprioceptive physical activities on balance control in elderly human subjects. NeuroscienceLetters, 273(2), 81-84.

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Functional Decrements Among Elderly