How Motor Imagery May Help Elderly

(Science in The News: sitn.hms.harvard.edu)

Aging often comes with a decline in motor function, which may be improved with physical activity. However, in some cases, physical activity can be difficult or could lead to injury. Motor imagery is a technique used in sports and rehabilitation in which the person imagines performing the desired motor function without execution. Motor imagery allows the person to practice the motor function without the use of physical performance, thereby aiding in ameliorating or preserving motor function without damage to the body (Saimpont, Malouin, Tousignant, & Jackson, 2013). Could motor imagery provide elderly a safe and effective supplement to exercise in order to keep movement fluid and precise?

(Waxman SG, Clinical Neuroanatomy, 26th ed)

Voluntary motor function is performed by the pyramidal motor system via activation of neurons in the primary motor cortex in the precentral gyrus, which synapses to the basal ganglia and the cerebellum, then to the pyramids in the medulla, which is formed by axons that project down the brainstem, then to the ventral root of the corticospinal tract of the descending motor pathway, on which it travels until eventually reaching the muscle. Motor impulses that control the trunk and midsection remain ipsilateral of the hemisphere of origin, while motor impulses that control the limbs are contralateral to the hemisphere of origin, crossing over, a process called decussation, at the pyramids. Voluntary motor function is also aided by the extrapyramidal motor system, performed by the basal ganglia and cerebellum, which modifies fine-tuning, timing, and coordination of motor function and maintains the stability and tone of muscles. Motor output is also modulated by sensory input, as the primary motor cortex and nonprimary motor cortex shall receive information orientation from the visual cortex, localization and vestibular (sense of balance and head orientation from the inner ear) information from the auditory cortex, touch information from the somatosensory cortex, and proprioceptive (sense of body position) and vestibular information from the cerebellum (Maeng, L, 2020).

Decline of motor function in old age could be caused by the gradual degeneration of motor cortical regions, the corpus callosum, and neurotransmitter systems. These age-related changes in the brain may affect both gross and fine motor function, as motor cortical regions are important to both production of motor output and sensory input important in movement, the corpus callosum is important to the integration of information between the hemispheres of the brain, and neurotransmitter systems, especially the dopaminergic system (Seidler, Bernard, Burutolu, Fling, Gordon, Gwin, Kwak, & Lipps, 2010), which are important to the pyramidal and extra-pyramidal motor systems.

(Drawing of the human brain, from the National Institute for Aging, National Institutes of Health, United States Department of Health and Human Services)

While some decline is part of the natural aging process, regular and frequent use of these systems may help to preserve or slow degeneration. Studies have shown that motor imagery in older adults produces simulation of the sensorimotor system, including “the premotor cortex, the supplementary motor area, subcortical structures such as the cerebellum and the basal ganglia, the inferior parietal cortex, the somatosensory and motion-sensitive visual cortices, and even the primary motor cortex” (Saimpont, et al., 2013). Training in motor imagery has been shown effective to significantly reduce attentional demands and postural oscillations during static balancing tasks in elderly (Hamel, & Lajoie, 2005) and improve one-legged balance in older women (Fansler, Poff, & Shepard, 1985). Motor imagery has also been shown to be effective in improving strength training in young adults (Reiser, Büsch, & Munzert, 2011) and rehabilitation in stroke victims (Hovington & Brouwer, 2010). Could motor imagery thereby help older individuals who have experienced a decline in gross and fine motor control and strength?

(Shutterstock)

In medicine, there is a heavy emphasis on extending life, but often this extension of life leads to other complications, such as loss of motor and sensory functions and neurodegenerative disease. There is an expectation that when one gets past a certain age, they will lose their senses and become ill, frail, and senile. While some decline is inevitable in old age, much of the time the majority of functioning can be preserved, and decline can be delayed. Illness and disease are not normal parts of aging. The healthcare system needs to be giving people the tools and the knowledge to preserve their quality of life in old age, not just an extension of years bedridden. Part of this includes dissemination of information, dispelling stereotypes and myths on aging, and developing and testing new interventions. Motor imagery appears to be one of the promising topics, but results are not overwhelmingly positive. I would like to see if implementation earlier in life makes this practice more effective.

Sources

Fansler, C. L., Poff, C. L., & Shepard, K. F. (1985). Effects of mental practice on balance in

elderly women. Physical Therapy, 65(9), 1332-1338.

Hamel, M. F., & Lajoie, Y. (2005). Mental imagery. Effects on static balance and attentional

demands of the elderly. Aging clinical and experimental research, 17(3), 223-228.

Hovington, C. L., & Brouwer, B. (2010). Guided motor imagery in healthy adults and stroke:

does strategy matter?. Neurorehabilitation and neural repair, 24(9), 851-857.

Maeng, L. (2020). Motor Systems and Functions. PSY 225: Brain Mind & Behavior. Wheaton

College, MA.

Reiser, M., Büsch, D., & Munzert, J. (2011). Strength gains by motor imagery with different

ratios of physical to mental practice. Frontiers in Psychology, 2, 194.

Saimpont, A., Malouin, F., Tousignant, B., & Jackson, P. L. (2013). Motor imagery and aging.

Journal of motor behavior, 45(1), 21-28.

Seidler, R. D., Bernard, J. A., Burutolu, T. B., Fling, B. W., Gordon, M. T., Gwin, J. T., Kwak, Y.

& Lipps, D. B. (2010). Motor control and aging: links to age-related brain structural, functional, and biochemical effects. Neuroscience & Biobehavioral Reviews, 34(5), 721-733.