|Mental representation; Aging; Motor imagery; Action
representation; Action planning
|The ability to mentally represent and effectively plan motor
actions underscores one’s successful intentions and lowers injury risk.
Recent research findings highlight the fact that as individuals enter
older adulthood, the ability to mentally represent their intentions and
successfully plan actions, declines. With the present article, we focus
on the potential of using motor imagery practice, a form of mental
representation, to improve motor planning and potentially reduce
the risk of fall injury. The idea being that in addition to physiotherapy
exercises, motor imagery practice can aid in reducing fall injury risk.
With that understanding, we can develop strategies to improve motor
representation among people, especially the elderly. The development
of such strategies can lead to enhanced quality of life for this growing
population in the US. With this paper, we will: (1) briefly review the
idea of mental representation associated with action planning and
motor imagery, (2) discuss the difficulty that has been described with
older adults, (3) provide a summary of selected studies testing various
practice methodologies using motor imagery, and finally, (4) provide
strategies for motor imagery practice.
|Mentally Representing Action and Motor Imagery
|The ability to mentally represent one’s intentions is a central issue
for understanding cognitive and motor behavior across the lifespan.
Mental representation has been described as an internal cognitive
construct that represents external reality. One commonly associated
form of mental representation is motor imagery, a key modality for
the creation of representations . Motor imagery, the focus of this
paper, involves the creation of representations involving action in
the context of movement planning and subsequent execution, that is,
action representation. Most motor programming theories support the
notion that action representation is a key feature in effective action
planning. One prominent view contends that action representation
involves an internal (forward) model, which is a neural system that
mentally simulates the dynamic behavior of the body in relation to the
environment [2-4]. The theory proposes that internal models make predictions (estimates) about the mapping of the self to parameters
of the external world. The result is processes that enable successful
planning and execution of action. Accompanying the forward
model propositions, and central to the discussion here, is the widely
acknowledged observation that simulation in the form of motor
imagery provides a window into the process of action representation
|Motor Imagery (MI)
|The ability to imagine future events and estimate consequences
is an essential part of the human cognition process. MI is defined
as an internal rehearsal or reenactment of movements from a firstperson
perspective without any overt physical movement. From
another perspective, MI, also known as kinesthetic imagery, is an
active cognitive process during which the representation of a specific
action is internally reproduced in working memory without any
overt motor output . In addition to the reasonable case that MI is
a reflection of action representation and motor planning; studies have
found that there is a high correlation between real and simulated
movements [10-13]. Furthermore, evidence has been reported
showing that MI follows the basic tenets of Fitts’ Law [14,15]. That is,
simulated movement duration, like actual movement, increases with
increasing task complexity. As opposed to visual imagery, defined as
the internal enactment or reenactment of perceptual experiences ,
neuroimaging and neuropsychological studies indicate that MI is more
affected by biomechanical (kinesthetic) constraints that are commonly
associated with action processing [15,17].
|One of the interesting hypothesized features of motor imagery is its
role in the prediction of one’s actions [11,12]. Suddendorf and Moore
 note, “The ability to imagine future events is an essential part
of human cognition” (p. 295). Imagery allows us to generate specific
predictions based upon past experience and allows us to answer ‘what
if ’ questions by making explicit and accessible the likely consequences
of a specific action. Mental simulations generate knowledge about
specific past events, and therefore make specific predictions . One
of the important aspects of an action plan is the ability to predict the
outcome and consequences of intended actions. Imagining an action
can serve several useful goals to that endeavor. According to Bourgeois
and Coello , motor representation can be viewed as a component
of a predictive system, which includes a neural process that simulates
through motor imagery the dynamic behavior of the body in relation
to the environment. This line of reasoning presents noteworthy
developmental issues associated with a person’s cognitive understanding
of environmental (perceptual) information and consequences, and
one’s physical capabilities.
|Mental representation in the elderly
|Recent observations indicate that the ability to mentally represent
motor actions declines with advancing age [21-29]. The following are a
few brief summaries of that work in regard to the general decline with
age. Mulder et al.  compared young and older adults on vividness of
movement imagery via questionnaire. The researchers found that older
adults were slightly worse than their younger counterparts, especially
from a first person perspective. Although not examined with that study,
a possible link between level of physical activity and imagery ability was
suggested. The assertion was that physical exercise in the elderly might
help preserve brain structures and mechanisms (frequently mentioned
is the parietal cortex) associated with mental representation. Personnier
et al. , used a mental chronometry paradigm to compare imagined
and executed arm pointing actions between young and older adults.
They reported that although it appeared that older adults displayed
the ability to mentally represent action via use of motor imagery, their
ability progressively deteriorated with advancing age as evidenced
by the declining quality of their MI (i.e. isochrony between executed
and imagined movements). The authors concluded that there was a
likelihood of weakness in the formulation of internal models of action
in the elderly. Testing the ability to mentally simulate/plan a complex
sequential action of the whole body (i.e., rising from the floor),
Saimpont et al.  reported that the elderly experienced significant
difficulties compared to young adults’ accuracy in action sequence and
reaction time. In a more recent review of this body of research ,
the authors concluded that MI accuracy for simple/usual upper-limb
movement’s appears well preserved with aging. However, advanced
aging did appear to affect the preservation and MI accuracy of upperlimb
actions with unusual biomechanical constraints.
|A real-world example and fall risk
|To illustrate the application of research findings to possible realworld
and everyday situations confronting the elderly, reports of
functional reach and reach estimation via motor imagery would appear
to have clinical implications. Functional reach, a frequently reported
assessment with the elderly, is the maximal distance an individual is
capable of reaching forward while standing, without taking a step or
losing balance. It is described as a dynamic measure of postural control.
The literature supports the observation that with advancing age there
is a sharp decline in functional reach [30,31]. Perhaps most relevant to
considerations of safety, research also indicates a significant relationship
between functional reach and risk of falling [32,33]. Additionally, in a recent study of young adults (mean age 22 years) and older adults
(66 years) examining the relationship between estimation of reach and
functional reach, Gabbard and Cordova  reported that only the
younger group showed a significant and positive association between
the two variables. In other words, the congruence between movement
planning (estimation) and execution was significantly better with the
younger group, as compared to the older adults.
|What is the connection between functional reach and estimation
of reach? Estimation of whether an object is reachable or not from a
specific body position constitutes an important aspect in efficient
and effective motor planning; a situation that has both scientific and
real-world implications. One of the initial steps in programming such
movements is to derive a perceptual estimate of the object’s distance
and location relative to the body. This means that an individual must be
able to perceive critical reach distances beyond which a particular reach
action is no longer afforded and to which a transition to another reach
mode must occur. For example, is the object close enough to reach while
seated, or do I need to stand? Furthermore, with older persons, could
I lose balance and fall? Such questions are not uncommon in everyday
situations, for example: reaching for an object on a table or reaching
and grasping a hand rail. An experimental tactic that provides insight
into this phase of motor planning (estimation) is estimation of reach
via use of MI. Use of that tactic has drawn the attention of researchers
that wish to examine the processes involved in action representation
and planning [35,36].
|Over estimation (Over optimistic?)
|Using the estimation of reach paradigm, Gabbard et al. 
reported that younger adults (mean age 20 years) were significantly
more accurate than older adults (mean age 77 years) when estimating
reach in peripersonal and extra personal space from a seating position.
Whereas, both groups made more errors in extrapersonal space, the
values were significantly higher for the older group; that is, they over
estimated to a greater extent. Caçola et al.  reported that accuracy
decreased as age increased when estimating reachability in peripersonal
and extrapersonal space using a 40 cm tool; the population ranged from
55 to 92 years. Lafargue et al.  also comparing young and older
adults, reported a failure of the older group to update their internal
model when asked to judge in advance whether or not they could
stand on an inclined plane. As predicted, the older adults significantly
overestimated their capabilities. A similar finding of overestimation
with advanced aging was reported by Noël et al.  and Sakurai et
al. . Both studies examined estimation of ability to step over an
obstacle. In their conclusions, Noël et al. noted that the overestimation
could be a major risk of falls in the elderly.
|To summarize, it would appear that older persons have difficulty
estimating possible movement outcomes and updating internal models,
resulting in dissociation between perception and action, a condition
that may promote risky motor planning and execution.
|Implications and therapeutic applications
|According to the Centers for Disease Control and Prevention
website, “Each year, one in every three adults age 65 and older falls.”
“Among older adults (those 65 or older), falls are the leading cause
of injury death.” These statistics display the critical need to better
understand the factors that constrain the elderly in regard to mental
representation and movement planning. Understanding these factors,
like the connection between reaching and falling, can allow for the
development of strategies to enhance movement efficiency and lower
associated injury risk.
|In support of the reach-fall link, four of 16 items on the Activities-
Specific Balance Confidence (ABC) Scale  are reach-specific
questions. This test is commonly cited as a self-report subjective
measure of perceived balance confidence in performing various
movement activities without falling. With the elderly, compared to
younger adults, there is a higher risk of falling during reach actions.
For example, if an older adult either significantly underestimates or
overestimates a reach target (e.g., drinking glass, table, and railing),
they may have more difficulty than a younger person in maintaining
postural control, often resulting in a fall.
|One proven effective therapy strategy for the recovery of motor
planning and control is MI practice. Use of MI has been documented
as an effective tool for: sport/motor performance [43-46], brain injury
, stroke [48-51] and other neuromotor impairments, e.g., . In
the context of neurological impairment, the literature suggests that
one of the key agents in movement recovery is use of MI to stimulate
otherwise non-active or impaired neural pathways. In addition,
Wohldmann et al.  reported evidence to support the hypothesis that
mental practice strengthens abstract mental representation that does
not involve specific effectors. That is, such practice strengthens ‘central’
features of the representation as well as representation of specific body
part processes, such as the hand and fingers.
|Of the training studies reviewed, unfortunately little has been
reported using older adults. One particular study was conducted by
Guttman et al. , who tested the effectiveness of MI practice with a
group of older persons (mean age 69 years) with chronic hemiparesis.
Practice involved performance of sit to stand and reaching to grasp
movements. The researchers found that MI practice has a positive effect
on actual execution.
|Strategies for improving motor imagery ability
|As noted earlier, information on motor imagery training with
the elderly is sparse. Based in large part on the literature and our
experience with such training, although individual differences and
capabilities should be a significant consideration, the target age group
recommendation is 65 to 85 years. In regard to training strategies for
specific impairments associated with stroke for example, once again the
patient should be considered in light of the individual impairment and
extent of the disability in reference to mental and physical constraints.
|From the information derived from the studies described here
and reviews on the general topic of MI practice [54,55], the following
recommendations and strategies appear worthy of consideration; that
is, used in combination with physiotherapy or as a stand-alone therapy
to improve motor planning.
|Clear and effective script of instructions: The script of instructions
should be used in early practice phases and needs to be as specific as
possible. For example: “Watch and feel your hand and fingers reaching
and grasping the mug. How will you grasp the mug and how fast will
you move as not to spill its contents?”
|Goal-setting: This is an important element of practice and a
strategy that can be induced via the script, verbally, or in combination
|First person internalizing: That is, focus on the self as the mental
image of the intended action. This state is the first component in the
actor-object dyad. Part of this dyad is an understanding of one’s physical
capabilities and potential consequences. Ask the participant to consider
the consequences if he or she were to miss-plan (over- or underestimate)
the event. What will you fall into? Do you feel confident in your ability to gain stability if you have to adjust your position quickly?
|Concentrate on the effectors: This is the specific part of the self
that is linked with the target. For example, focus on the arm/hand when
intending to reach and grasp an object.
|Focus on the visual cues (target/object/goal): Concentrate on
the end point of the intended action–the target. For example, where
does my hand need to be to grasp the object securely? With tasks such
aiming at a target, when timing is a factor, auditory cues in the form of
a metronome have been effective.
|Reinforcement on kinesthetically ‘feeling’ execution of
movement: Research indicates clearly that ‘feeling’ rather than just
seeing oneself perform the action promotes better mental representation
for movement via internalization.
|Combine physiotherapy with mental practice: By practicing
actual movements, participants gain a better understanding of their
physical capabilities and develop movement endurance, a problem that
is common in the elderly. Physical practice affords the opportunity to
test one’s capabilities. Furthermore, research shows that mental practice
combined with physical practice enhances actual performance outcome
|Progress from simple to more complex actions: Do this when
practicing both imagined and actual execution movements.
|Practice 15-60 minutes, 3 times/week for 4 weeks: This has
been one of the most commonly reported practice durations with a
variety of patient impairments. Obviously, this should be viewed as an
approximate benchmark with the progression principle strictly applied.
|The intent of this paper was to bring attention to the benefits of
motor imagery and propose potential use of motor imagery practice
(therapy) in the physiotherapy setting. Research indicates that such
practice can improve motor planning, subsequently reducing the risk
of fall injury, especially in the elderly. Whereas motor imagery practice
can be a stand-alone program, there is good evidence that when used in
combination with physical practice, results for improved overall motor
performance can be significant.
- Kosslyn SM, Thompson WL, Ganis G (2006) The case for mental imagery. Oxford University Press, New York.
- Penhune VB, Steele CJ (2012) Parallel contributions of cerebellar, striatal and M1 mechanisms to motor sequence learning. Behav Brain Res 226: 579-591.
- Schubotz R (2007) Prediction of external events with our motor system: towards a new framework. Trends Cogn Sci 11: 211-218.
- Wolpert DM (1997) Computational approaches to motor control. Trends Cogn Sci 1: 209-216.
- Chabeauti PY, Assaiante C, Vaugoyeau M (2012) Extreme short-term environmental constraints do not update internal models of action as assessed frommotor imagery in adults. Neuroscience 222: 69-74.
- Jeannerod M (2001) Neural simulation of action: a unifying mechanism for motor cognition. Neuroimage 14: S103-109.
- Munzert J, Lorey B, Zentgraf K (2009) Cognitive motor processes: the role of motor imagery in the study of motor representations. Brain Res Rev 60: 306-326.
- Wintermute S (2012) Imagery in cognitive architecture: representation and control at multiplelevels of abstraction. Cogn Syst Res19-20: 1-29.
- Decety J, Grezes J (1999) Neural mechanisms subserving the perception of human actions. Trends Cogn Sci 3: 172-178.
- Burianová H, Marstaller L, Sowman P, Tesan G, Richl AN, et al. (2013) Multimodal functional imaging of motor imagery using a novel paradigm. Neuroimage 71: 50-58.
- Kunz BR, Creem-Regehr SH, Thompson WB (2009) Evidence for motor simulation in imagined locomotion. J Exp Psychol Hum Percept Perform 35: 1458-1471.
- Lorey B, Bischoff M, Pilgramm S, Stark R, Munzert J, et al. (2010) The embodied nature of motor imagery: the influence of posture and perspective.Exp Brain Res 194: 233-243.
- Lorey B, Nauman T, Pilgramm S, Peterman C, Bischoff M, et al. (2013) How equivalent are the action execution, imagery, and observation of intransitive movements? revisiting the concept of somatotopy during action simulation. Brain Cogn 81: 139-150.
- Solodkin A, Hlustik P, Chen EE, Small SL (2004) Fine modulation in network activation during motor execution and motor imagery. Cereb Cortex 14: 1246-1255.
- Stevens JA (2005) Interference effects demonstrate distinct roles for visual and motor imagery during the mental representation of human action. Cognition 95: 329-350.
- Barsalou LW (2008) Grounded cognition. Annu Rev Psychol 59: 617-645.
- Pelgrims B, Andres M, Olivier E (2005) Motor imagery while judging object-hand interactions. Neuroreport 16: 1193-1196.
- Suddendorf T, Moore C (2011) Introduction to the special edition: the development of episodic foresight. Cogn Dev 26: 295-298.
- Moulton ST, Kosslyn SM (2009) Imagining predictions: mental imagery as mental emulation. Philos Trans R Soc London 364: 1273-1280.
- Bourgeois J, Coello,Y (2009) Role of inertial properties of the upper limb on the perception of the boundary of personal space. Psychol Française 54: 225-239.
- Beauchet O, Annweiler C, Assal F, Bridenbaugh S, Hermann RR, et al. (2010) Imagined timed up & go test: a new tool to assess higher-level gait and balance disorders in older adults? J Neurol Sci 294: 102-106.
- Caçola P, Roberson J, Gabbard C (2013) Aging in movement representations for sequential finger movements: a comparison between young, middle-aged, and older adults. Brain Cogn 82: 1-5.
- De Simone L, Tomasino B, Marusic N, Eleopra R, Rumiati RI (2013) The effects of healthy aging on mental imagery as revealed by egocentric and allocentric mental spatial transformations. Acta Psychol (Amst) 143: 146-156.
- Mulder T, Hochstenbach JBH, Heuvelena MJG, Otter AR (2008) Motor imagery: the relation between age and imagery capacity. Hum Mov Sci 26: 203-211
- Personnier P, Bally Y, Papaxanthis C (2010) Mentally represented motor actions in normal aging III: electromyographic features of imagined arm movements. Behav Brain Res 206: 184-190.
- Saimpont A, Mourey F, Manckoundia P, Pfitzenmeyer P, Pozzo T (2010) Aging affects the mental simulation/planning of the ‘‘rising from the floor’’ sequence. Arch Gerontol Geriatr 51: 41-e45.
- Saimpont A, Malouin F, Tousignant B, Jackson P (2013) Motor imagery and aging. J Mot Behav 45: 21-28.
- Skoura X, Personnier P, Vinter A, Pozzo T, Papaxanthis C (2008) Decline in motor prediction in elderly subjects: right versus left arm differences in mentally simulated motor actions. Cortex 44: 1271-1278.
- Zapparoli L, Invernizzi P, Gandola M, Verardi M, Berlingeri M, et al. (2013) Mental images across the adult lifespan: a behavioural and fMRI investigation of motor execution and motor imagery. Exp Brain Res.
- Costarella M, Monteleone L, Steindler R, Zuccaro SM (2010) Decline of physical and cognitive conditions in the elderly measured through thefunctional reach test and the mini-mental state examination. Arch Gerontol Geriatr 50: 332-337.
- Zuccaro SM, Steindler R, Scena S, Costarella M (2012) Changes of psychical and physical conditions in the elderly after a four-year follow-up. Arch Gerontol Geriatr 54: 72-77.
- Duncan PW, Weiner DK, Chandler J, Studenski S (1990) Functional reach: a new clinical measure of balance. J Gerontol 45: M192-M197.
- Huang H, Gau M, Chuan W, Kernohan G (2003) Assessing risk of falling in older adults. Public Health Nurs 20: 99-411.
- Gabbard C, Cordova A (2013) Association between imagined and actual functional reach: a comparison of young and older adults. Arch Gerontol Geriatr 56: 487-491.
- Coello Y, Bartolo A, Amiri B, Devanne H, Houdayer E, et al. (2008) Perceiving what is reachable depends on motor representations: evidence from transcranial magnetic stimulation study. PLoS ONE 3: e2862.
- Lamm C, Fischer MH, Decety J (2007) Predicting the actions of others taps into one’s own somatosensory representations: a functional MRI study. Neuropsychologia 45: 2480-2491.
- Gabbard C, Cacola P, Cordova A (2011) Is there an advanced aging effect on the ability to mentally represent action? Arch Gerontol Geriatr 53: 206-209.
- Caçola P, Martinez A, Ray C (2012) The ability to modulate peripersonal and extrapersonal reach space via tool use among the elderly. Arch Gerontol Geriatr 56: 383-388.
- Lafargue G, Noël M, Luyat M (2013) In the elderly, failure to update internal models leads to overoptimistic predictions about upcoming actions. PLoS ONE 8: e51218.
- Noël M, Bernard A, Luyat M (2011) The overestimation of performance: a specific bias of aging? Geriatri Psychol Neuropsychiatr Vieil 9: 287-294.
- Sakurai R, Fujiwara Y, Ishihara M, Higuch T, Uchida H, et al. (2013) BMC Geriatr 13: 44.
- Powell LE, Myers AM (1995) The activities-specific balance confidence (ABC) scale. J Gerontol A Biol Sci Med Sci 50A: M28-M34.
- Gentili R, Han CE, Schweighofer N, Papaxanthis C (2010) Motor learning without doing: trial-by-trial improvement in motor performance during mental training. J Neurophysiol 104:774-783.
- Guillot A, Tolleron C, Collet C (2010) Does motor imagery enhance stretching and flexibility? J Sports Sci 28: 291-298.
- Zhang H, Xu L, Wang S, Xie B, Gui J, et al. (2011) Behavioral improvements and brain functional alterations by motor imagery training. Brain.
- Lebon F, Collet C, Guillot A (2010) Benefits of motor imagery training on muscle strength. J Strength Cond Res 24: 1680-1687.
- Oostra KM, Vereecke A, Jones K, Vanderstraeten G, Vingerhoets G (2012) Motor imagery ability in patients with traumatic brain injury. Arch Phys Med Rehabil 93: 828-833.
- Guttman A, Burstin A, Brown R, Bril S, Dickstein R (2012) Motor imagerypractice for improving sit an stand and reaching to grasp in individuals withpoststroke hemiparesis. Top Stroke Rehabil 19: 306-319.
- Hosseini SA, Fallahpour M, Syadi M, Gharib M, Haghgoo H (2012) The impact of mental practice on stroke patient’s postural balance. Journal of the Neurol Sci.
- Malouin F, Richards CL (2010) Mental practice for relearning locomotor skills.Phys Ther 90: 240-251.
- Sharma N, Simmons LH, Jones PS, Day DJ, Carpenter TA, et al. (2009) Motor imagery after subcortical stroke: a functional magnetic resonance imaging study. Stroke 40: 1315-1324.
- Heremans E, Nieuwboer A, Spildooren J, De Bondt S, D'Hooge AM, et al. (2012) Cued motor imagery in patients with multiple sclerosis. Neuroscience 206: 115-121.
- Wohldmann EL, Healy AF, Bourne LE (2008) A mental practice superiorityeffect: less retroactive interference and more transfer than physical practice. J Exp Psychol Learn Mem Cogn 34: 823-833.
- Langhome P, Coupar F, Pollock A (2009) Motor recovery after stroke: a systematic review. Lancet Neurol 8: 741-754.
- Schuster C, Hilfiker R, Amit O, Scheidhauer A, Andrews B, et al. (2011) Best practice for motor imagery: a systematic literature review on motor imagery training elements in five different disciplines. BMC Med 9: 75.
- Reiser M, Busch D, Munzert J (2011) Strength gains by motor imagery withdifferent ratios of physical to mental practice. Front Psychol 2: 194.