Randhawa, Bubblepreet MSPT; Harris, Susan PT, PhD, FAPTA; Boyd, Lara A. PT, PhD
Motor imagery (MI) is the mentalrepresentation of movement without any actual body motion.1,2 MI is a complex process, involving the use of sensory and perceptual memories as they relate to motor actions. MI practice has been shown to facilitate motor skill learning in non-disabled individuals.3,4 Importantly, MI may be experienced from either a visual or kinesthetic perspective. Visual imagery refers to self-visualization of a movement from either the perspective of the first person (eg, visualizing the movement as if a camera were on the head) or the third person (eg, visualizing the movement as a spectator).1 Alternately, kinesthetic imagery requires a person to imagine a movement from the first person perspective, performing the movement mentally and experiencing the actual situation and sensations.3 These 2 forms of MI are not mutually exclusive and may be simultaneously experienced.
MI has been proposed as a potential adjunct to physical rehabilitation because it allows for practice of movements in a safe manner, both within and outside of the therapeutic setting. The impact of MI on motor skill learning and rehabilitation has been studied in individuals with stroke5–8 and spinal cord injury.9,10 Brain imaging work exploring the neural correlates of MI in non-disabled individuals has demonstrated the importance of the basal ganglia and supplementary motor area (SMA) during mentally imagined movements.11–13 However, the network activated during MI has been shown to be shifted by Parkinson disease (PD)11 to be more reliant on the SMA due to the exclusion of the basal ganglia. Because PD disrupts basal ganglia function and causes motor deficits, it is tempting to conclude that this disease will also affect MI. However, no work has directly assessed the question of whether people with PD can imagine movement. One impediment to work considering MI ability in individuals with PD is the need for a reliable and valid MI assessment scale.
To date, several studies have considered whether MI can positively alter behavior (eg, motor learning)14 or function (eg, daily function)15 in individuals with PD. However, this work has not directly tested MI ability but rather inferred the effects of MI on motor behavior using pre/post designs that assess changes associated with MI. For example, in a single session, Yaguez et al14 trained individuals with PD using a combination of physical motor and mental imagery practice; neither improved movement. A more positive result was demonstrated by Tamir et al,15 who noted that MI practice reduced losses of daily function attributable to bradykinesia. Although this past work is important, neither of these studies directly indexed MI ability in people with PD. Thus, the essential next step in this line of research is establishing the reliability and validity of a measurement tool, which can then be used in investigations of the MI capability of individuals with PD. This was the main aim of this study.
In stroke and non-disabled populations, MI is judged by individual responses to different questionnaires such as the Movement Imagery Questionnaire (MIQ),16 the revised and shorter version of the MIQ—the MIQ-R,17 the Vividness of Motor Imagery Questionnaire (VMIQ),18 and the Kinesthetic and Visual Imagery Questionnaire (KVIQ).19 These questionnaires assess imagery ability using individual responses on ordinal rating scales. The MIQ scale was developed to gauge MI ability in non-disabled adults and athletes; it assesses both kinesthetic and visual imagery ability.16 However, the MIQ is quite long (18 items; 9 visual and 9 kinesthetic subscales), and its movement elements are geared toward athletics. Thus, use of the MIQ in populations with neurological disease or brain damage is problematic because some of the tested movements are complex (eg, front roll), and completing it can be fatiguing owing to its length.
In an effort to reduce the time taken to administer the MIQ, its authors produced a shorter version, the MIQ-R17 that includes only 8 items (4 visual and 4 kinesthetic subscales), scored on a 7-point Likert scale. Concurrent validity of the MIQ-R showed it to be comparable to the MIQ in non-disabled individuals.17 The MIQ-R is a self-report questionnaire in which participants first perform movements, then imagine movements, and then self-score their mental imagery performance. Lorant and Nicholas20 assessed test-retest reliability of the MIQ-R, reporting correlation coefficients of r = 0.86 and r = 0.90 for the visual and kinesthetic subscales, respectively. One impediment to using the MIQ-R in individuals with neuropathology is its reliance on fairly difficult movements (eg, stand on 1 foot, jump straight in the air as high as possible).
A separate but commonly used scale, the VMIQ18 measures the vividness of imagery with 48 self-report items (24 visual and 24 kinesthetic items, grouped into subscales) on a 5-point Likert scale. However, unlike the MIQ-R, participants are not required to perform the movement before imagining it. The test-retest reliability of the VMIQ during a 3-week interval was r = 0.76, and some have questioned the ability of VMIQ to adequately index kinesthetic imagery.19 In large part, this criticism stems from a poor correlation between VMIQ kinesthetic scores and the kinesthetic subscale of the MIQ (agreement correlation coefficient = 0.49).17
Given the length of testing and/or the difficulty of the required movements, none of the existing MI scales (ie, MIQ, MIQ-R, or VMIQ) has been considered appropriate for individuals with neuropathology. Thus, Malouin et al19 developed the KVIQ for use with both non-disabled individuals and people with disabilities (ie, stroke). The KVIQ assesses both visual and kinesthetic components of MI, and it is not a self-administered test. The questionnaire has 20 items (Table 1) and uses a 5-point Likert scale (5 = clear and intense image; 1 = no image, no sensation). The KVIQ is suitable for people who, for different reasons, need guidance in rating imagery and/or are unable to stand or perform physically complex movements. To date, the test-retest reliability and internal consistency of the KVIQ have been reported in non-disabled individuals and in persons with stroke.19 The intraclass correlation coefficients (ICCs) for test-retest reliability for non-disabled persons ranged from 0.72 to 0.81 and from 0.81 to 0.90 for a group of individuals with stroke, suggesting that the KVIQ can be reliably used in non-disabled persons and individuals poststroke. Internal consistency (Cronbach α) ranged from 0.87 to 0.94, indicating that the KVIQ has item homogeneity and measures the same construct. However, at present, the reliability and validity of the KVIQ have only been established in people with stroke and non-disabled controls. Owing to the large differences between PD and stroke, the reliability and validity of the KVIQ cannot be directly extrapolated from past work. Further, because the neural circuits used during imagery are also those that are directly affected by PD (ie, the basal ganglia and SMA), MI in this population may be especially problematic.11,12,21
Therefore, the primary purposes of our study were to examine (1) the test-retest reliability and (2) concurrent validity of the KVIQ in individuals with PD. We selected the KVIQ because the movements required are more suitable for individuals with neuropathology. In addition, it taps an important component of imagery—the vividness or intensity of imagery, which is considered a measure of imagery ability.19 We selected the MIQ-R as the gold standard because it is short, has high test-retest reliability,20 and contains both visual and kinesthetic subscales.17,22 A secondary purpose of our work was to separately examine the test-retest reliability of the KVIQ for the subcomponents of axial movements (items 1, 2, and 6; Table 1). This secondary aim was motivated by past work showing that axial movements are disrupted earlier in the course of PD.19,23–25
Eleven individuals with mild to moderate PD (Hoehn and Yahr stages: 1–2.5; ages: 50–75 years; 7 women) participated. All had a neurologist-confirmed diagnosis of PD and were right-hand dominant. PD predominantly affected the right side in 6 of the 11 participants. To characterize disease status, scores on the Unified Parkinson's Disease Rating Scale III and Hoehn and Yahr stage were determined by a physical therapist (Table 2). Exclusion criteria included (1) age older than 80; (2) cognitive dysfunction (ie, Montreal Cognitive Assessment < 26); (3) any psychiatric disturbances; (4) any neuromuscular, skeletal, cardiovascular conditions that might interfere in completing the questionnaire; and (5) severe PD (Hoehn and Yahr stage > 3), making it difficult to maintain sitting balance or to move in response to a command to perform movement.
Participants were tested while on their regular medication schedule; interviews confirmed that medication status did not change during the period of study participation. To control for medication-induced fluctuations in function, all participants took their medication 1.5 hours before each testing session. To avoid medication-dosing effects, participants were tested at the same time of day for each of the 2 sessions. All participants gave informed, written consent for their participation in the study and all procedures were institutionally and ethically approved. All tests were conducted by a physical therapist (first author) with previous experience using mental imagery.
Reliability and Validity Study Procedures
To examine the test-retest reliability of the KVIQ, the same examiner (first author) assessed participants twice, 5 to 12 days apart. To evaluate the concurrent validity of the KVIQ with the MIQ-R, participants completed both tests in random order during their second visit.
Administration of the KVIQ and MIQ-R
Participants were tested in a quiet room with the door closed. Administration of the KVIQ followed the procedures outlined by Malouin et al19,25: (1) the participant was asked to assume the starting position; (2) the movement was described and the participant was asked to perform it; (3) the participant then returned to the starting position and imagined the movement that was just executed (the examiner verified that there was no actual movement); (4) the participant was asked to rate ease/difficulty with which they imagined the movement on the 5-point Likert scale, for clarity/vividness of the visual image or the intensity of the sensations associated with the imagined movement. The KVIQ involves simple movements of head, shoulders, trunk, upper limbs, and lower limbs (Table 1). All movements in Table 1 (except those labeled axial) were tested on both left and right sides (left and right data were collapsed into total KVIQ scores; see Data Analyses section). Participants were tested first on visual imagery and second on kinesthetic imagery. KVIQ testing took approximately 20 to 25 minutes; all participants were able to complete each item of the KVIQ.
On the second visit, participants were assessed on both the MIQ-R and KVIQ. For the MIQ-R, participants were asked to read the instructions carefully and ask the examiner questions if necessary. When the examiner thought that a participant understood how to complete the questionnaire, she left the room to allow the participant to complete the self-report of their MI ability (the examiner continued to observe the self-administration of the MIQ-R through a glass window). During the MIQ-R, participants first performed the movement physically, then completed visual or kinesthetic imagery of the movement, and finally recorded the score themselves on the score sheet. Although the time allowed to complete the questionnaire was unlimited, participants took approximately 10 to 15 minutes for completion. Once the participants signaled that they had finished the questionnaire, the examiner returned to the room to debrief them on the MIQ-R. All indicated that they were able to perform every movement required by the MIQ-R.
For each session, the maximal score for each of the visual and kinesthetic subscales of the KVIQ (70 maximal possible score for each the visual and kinesthetic subscales, 15 maximal possible score for axial visual and axial kinesthetic subscales, 170 total) and the maximal score for each of axial visual and axial kinesthetic subscales (15 maximal possible score) were calculated. To examine the extent to which measurements were consistent over time (test-retest reliability), ICCs were calculated (ICC = 1,1; 1-way, random-effects model) using SPSS software (version 15.0; SPSS Inc., Chicago, Illinois) with a 95% confidence interval. An ICC of ≥ 0.80 was set for test-retest reliability as “acceptable” per previous published literature.26,27
To examine the concurrent validity of the KVIQ in our sample of individuals with PD, we recorded the scores of the KVIQ and the MIQ-R (the gold standard criterion test) on the second visit and calculated the relationship between the 2 questionnaires (Spearman rank order correlation coefficient with 95% confidence intervals).
The mean time interval between test-retest sessions was 7.27 days (range: 5–12 days). There was no significant difference between total KVIQ scores or visual or kinesthetic subscales for the test-retest sessions (P > 0.05). Axial kinesthetic imagery also did not differ between the sessions; however, there was a difference between axial visual imagery from test to retest (F test = 6.81, P = 0.03). Individual scores recorded at test and retest are in Table 2.
Group scores were also recorded at test and retest to study variations in the individual components of imagery, ie, visual and kinesthetic KVIQ subscales, as shown in Table 3. The overall mean KVIQ score was 139.96 with an ICC of 0.87 for test-retest reliability. The comparison between raw data subscores from the means combined at test and retest revealed that individuals with PD had slightly higher scores for visual imagery than for kinesthetic imagery as shown in Table 3. The test-retest reliability for axial visual imagery (ICC = 0.74) and axial kinesthetic imagery (ICC = 0.79) were slightly lower than those for limb imagery (ICC = 0.82–0.95). Bland-Altman plots (Fig. 1) display the distributions for between-session repeatability for all subjects. Higher distributions of datapoints or scores about zero indicate higher between-session repeatability. Almost all participants performed slightly better on the second visit, which may reflect a modest practice effect. However, this between-session change was small and not statistically significant (P > 0.05) except for axial visual imagery.
The Spearman rank order correlation coefficient between the total KVIQ second session score and the total MIQ-R score (gold standard) was 0.93. The Spearman r between the kinesthetic and visual subscales of the KVIQ and MIQ-R was 0.94 and 0.88, respectively. Scores for the KVIQ and MIQ-R were consistent among subjects (Fig. 2); correlations between kinesthetic and visual scores of the KVIQ and MIQ-R among individual participants are illustrated in Figure 2A through C, respectively.
The results of this study illustrate that that the KVIQ reliably indexes MI ability in individuals with PD. Overall, reliability of the total KVIQ score was good to excellent (ICC = 0.87). Concurrent validity of the KVIQ and MIQ-R was also good (rho = 0.93). This is the first study to present the reliability and validity of any MI questionnaire for individuals with PD. Our data are consistent with those of Malouin et al,19 who showed similar results in non-disabled people and in those poststroke.
One interesting finding in this study is that individuals with PD were not as reliable when imaging axial visual movements compared with limb movements. Although only 1 participant demonstrated clinical deficits in axial involvement and all were in early stages of PD (Hoehn and Yahr stages 1 and 2), differences in axial mental imagery were noted (significant differences in axial visual imagery; P = 0.03). Difficulty in axial imagery may be a result of changes in muscle that accompany PD. For example, other data have shown increased axial tone28,29 in individuals with PD compared with non-disabled controls.30 The increased axial resistance during trunk movements in individuals with PD could result from altered medium- or long-length reflex loops (eg, vestibulospinal and cervicospinal reflexes).30–32 Alternately, the variability in axial movements in our data may be a result of the small number of items (n = 3) in the KVIQ that tap these types of movements (7 items test limb imagery). Yet, it is also possible that difficulty imagining axial movements precedes the onset of clinical motor deficits. It may be that the progression of PD is more advanced at a neural level than at a functional or clinical level, even in early stages of PD. It is tempting to conclude that testing axial imagery of movements may be a useful adjunctive clinical assessment to evaluate disease severity and progression. Future work is needed to verify this hypothesis.
The data suggest a significant relationship between scores on the KVIQ and MIQ-R in individuals with mild to moderate PD. According to Portney and Watkins,33 correlation coefficients greater than 0.75 are regarded as good to excellent. Test-retest correlation coefficients for the total score as well as for subgroup analyses of KVIQ and MIQ-R exceeded rho = 0.85, suggesting good to excellent relationships between the KVIQ and MIQ-R.
The concurrent validity results of this study suggest that the KVIQ is comparable to the MIQ-R in indexing MI in persons with PD. As the MIQ-R is a more complex and physically challenging test, it is encouraging that the KVIQ, an easy questionnaire to administer that contains much more appropriate movements for individuals with neuropathology, can yield similar results. Further, the MIQ-R does not index imagery clarity/vividness, a key element of MI. Finally, the MIQ-R relies on self-administration and self-rating. Although self-administration may be a benefit for non-disabled individuals, in populations with neuropathology, it may be more important to ensure that the required movements can be performed accurately and safely via administration by an experienced person.
The results of this study should be considered with care. Our sample was relatively small, only 11 participants, who were all in the early stages of PD. Consequently, our findings may not apply to individuals in more advanced stages of the disease. Further, we did not test a control group. However, the KVIQ and MIQ-R data for non-disabled control subjects have been reported previously.19 Finally, because we administered the MIQ-R in the second session for all participants, it is possible that we induced an order effect. However, we believe that this had a minimal impact on data because we noted a high correlation between KVIQ and MIQ (rho = 0.93).
CONCLUSIONS AND CLINICAL IMPLICATIONS
Our results demonstrate that the KVIQ can be used in future work to reliably index initial MI ability and/or shifts in MI capability that may occur over the course of practice during rehabilitation or motor learning in individuals with PD. We recommend the KVIQ as a tool to index MI ability because it is (1) reliable and valid, (2) relatively short (20 minutes to complete), (3) contains movements that are safe and appropriate for individuals with neuropathology, and (4) is not self-administered but scored by a tester. When compared with the MIQ-R, the movements required by the KVIQ are more appropriate for individuals with neuropathology. Because the KVIQ now has known reliability and validity, we suggest that it is a good choice for clinicians who may wish to index MI ability in people with PD before implementing imagery as an adjunct therapy. Further, we believe that establishing the reliability and validity of the KVIQ for people with PD may facilitate its use in trials that seek to determine whether MI ability can be changed by experimental or clinical interventions.
1. Guillot A, Collet C. Contribution from neurophysiological and psychological methods to the study of motor imagery. Brain Res Brain Res Rev. 2005; 50:387–397.
2. Solodkin A, Hlustik P, Chen EE, Small SL. Fine modulation in network activation during motor execution and motor imagery. Cereb Cortex. 2004; 14:1246–1255.
3. Dickstein R, Deutsch JE. Motor imagery in physical therapist practice. Phys Ther. 2007; 87:942–953.
4. Jeannerod M, Decety J. Mental motor imagery: a window into the representational stages of action. Curr Opin Neurobiol. 1995; 5:727–732.
5. Braun SM, Beurskens AJ, Borm PJ, Schack T, Wade DT. The effects of mental practice in stroke rehabilitation: a systematic review. Arch Phys Med Rehabil. 2006; 87:842–852.
6. Muller K, Butefisch CM, Seitz RJ, Homberg V. Mental practice improves hand function after hemiparetic stroke. Restor Neurol Neurosci. 2007; 25:501–511.
7. Simmons L, Sharma N, Baron JC, Pomeroy VM. Motor imagery to enhance recovery after subcortical stroke: who might benefit, daily dose, and potential effects. Neurorehabil Neural Repair. 2008; 22:458–467.
8. Verbunt JA, Seelen HA, Ramos FP, Michielsen BH, Wetzelaer WL, Moennekens M. Mental practice-based rehabilitation training to improve arm function and daily activity performance in stroke patients: a randomized clinical trial. BMC Neurol. 2008; 8:7.
9. Alkadhi H, Brugger P, Boendermaker SH, et al. What disconnection tells about motor imagery: evidence from paraplegic patients. Cereb Cortex. 2005; 15:131–140.
10. Cramer SC, Orr EL, Cohen MJ, Lacourse MG. Effects of motor imagery training after chronic, complete spinal cord injury. Exp Brain Res. 2007; 177:233–242.
11. Thobois S, Dominey PF, Decety J, et al. Motor imagery in normal subjects and in asymmetrical Parkinson's disease: a PET study. Neurology. 2000; 55:996–1002.
12. Gerardin E, Sirigu A, Lehericy S, et al. Partially overlapping neural networks for real and imagined hand movements. Cereb Cortex. 2000; 10:1093–1104.
13. Li CR. Impairment of motor imagery in putamen lesions in humans. Neurosci Lett. 2000; 287:13–16.
14. Yaguez L, Canavan AG, Lange HW, Homberg V. Motor learning by imagery is differentially affected in Parkinson's and Huntington's diseases. Behav Brain Res. 1999; 102:115–127.
15. Tamir R, Dickstein R, Huberman M. Integration of motor imagery and physical practice in group treatment applied to subjects with parkinson's disease. Neurorehabil Neural Repair. 2007; 21:68–75.
16. Hall CR, Pongrac J. Movement Imagery Questionnaire. London, Ontario, Canada: The University of Western Ontario, Faculty of Physical Education; 1983.
17. Hall CR, Martin KA. Measuring movement imagery abilities: a revision of the movement imagery questionnaire. J Ment Imagery. 1997; 21:143–154.
18. Isaac A, Marks DF, Russell DG. An instrument for assessing imagery of movement: the vividness of movement imagery questionnaire (VMIQ). J Ment Imagery. 1986; 10:23–30.
19. Malouin F, Richards CL, Jackson PL, Lafleur MF, Durand A, Doyon J. The kinesthetic and visual imagery questionnaire (KVIQ) for assessing motor imagery in persons with physical disabilities: a reliability and construct validity study. J Neurol Phys Ther. 2007; 31:20–29.
20. Lorant J, Nicholas A. Validation de la traduction francaise du movement imagery questionnaire-revised (MIQ-R). Sci Motricite. 2004; 53:57–68.
21. Helmich RC, de Lange FP, Bloem BR, Toni I. Cerebral compensation during motor imagery in Parkinson's disease. Neuropsychologia. 2007; 45:2201–2215.
22. Campos A, Perez MJ. A factor analysis study of two measures of mental imagery. Percept Mot Skills. 1990; 71:995–1001.
23. Hong M, Perlmutter JS, Earhart GM. A kinematic and electromyographic analysis of turning in people with Parkinson disease. Neurorehabil Neural Repair. 2009; 23:166–176.
24. Lundy-Ekman L. Neuroscience: Fundamentals for Rehabilitation. Philadelphia, PA: WB Saunders; 1998.
25. Malouin F, Richards CL, Durand A, Doyon J. Clinical assessment of motor imagery after stroke. Neurorehabil Neural Repair. 2008; 22:330–340.
26. Harris SR, Daniels LE. Reliability and validity of the Harris infant neuromotor test. J Pediatr. 2001; 139:249–253.
27. Anastasi A. Psychological Testing. New York, NY: MacMillan Publishing Company; 1988.
28. Nagumo K, Hirayama K. A study on truncal rigidity in parkinsonism—evaluation of diagnostic test and electrophysiological study. Rinsho Shinkeigaku. 1993; 33:27–35.
29. Nagumo K, Hirayama K. Axial (neck and trunk) rigidity in Parkinson's disease, striatonigral degeneration and progressive supranuclear palsy. Rinsho Shinkeigaku. 1996; 36:1129–1135.
30. Wright WG, Gurfinkel V, Nutt J, Horak FB, Cordo PJ. Axial hypertonicity in Parkinson's disease: direct measurements of trunk and hip torque. Exp Neurol. 2007; 208:38–46.
31. Bergui M, Lopiano L, Paglia G, Quattrocolo G, Scarzella L, Bergamasco B. Stretch reflex of quadriceps femoris and its relation to rigidity in Parkinson's disease. Acta Neurol Scand. 1992; 86:226–229.
32. Lee RG. Pathophysiology of rigidity and akinesia in Parkinson's disease. Eur Neurol. 1989; 29 (suppl 1):13–18.
33. Portney L, Watkins M. Foundations of Clinical Research: Applications to Practice. 2nd ed. Upper Saddle River, NJ: Prentice-Hall Inc.; 2000.
motor imagery; Parkinson disease; motor imagery questionnaire; test-retest reliability