**1. Introduction**

Motor imagery (MI) comprises imagining a movement without executing it to optimize motor skills [1]. It is a specific cognitive process in which the planning of a movement is carried out without executing it through actual physical movement [2], and it is observed to have the same components and involve the same brain areas as when a real movement is performed [2,3]. This process can also be explained thanks to the existence of the psychoneuromuscular theory, whose foundations support the idea that MI improves motor learning based on the role played by mirror neurons when these are activated during the visualization of a movement in mental practice [2]. In turn, the motor schema involved in the actual activity is reinforced during MI so that the processes occurring during imagery aid performance, reinforcing coordination patterns for motor skill development [2].

Therefore, MI practice is a technique that is increasingly used in the therapeutic context to improve the performance of specific motor skills, and whenever possible, it is

**Citation:** Suárez Rozo, M.E.; Trapero-Asenjo, S.; Pecos-Martín, D.; Fernández-Carnero, S.; Gallego-Izquierdo, T.; Jiménez Rejano, J.J.; Nunez-Nagy, S. Reliability of the Spanish Version of the Movement Imagery Questionnaire-3 (MIQ-3) and Characteristics of Motor Imagery in Institutionalized Elderly People. *J. Clin. Med.* **2022**, *11*, 6076. https:// doi.org/10.3390/jcm11206076

Academic Editor: Gianluca Testa

Received: 13 September 2022 Accepted: 8 October 2022 Published: 14 October 2022

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**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

combined with physical practice [2,4,5]. Thus, MI practice has been studied in healthy subjects, athletes [6–12], as well as in multiple neurological conditions [13–16] and pain conditions [17–20], among others. It has also been used in combination with virtual reality using brain–computer-interface-based systems in people with neurological sequelae [20,21].

A recent systematic review showed improved balance, mobility, and gait speed among the therapeutic benefits of MI training in older people without neurological conditions [22]. For an MI training program to be effective, the ability to generate imagery needs to be assessed [23]. However, there are few studies on MI capacity in the elderly, specifically in institutionalized elderly people. As is well-known, the institutionalization of elderly people in nursing homes is one of the best options when they can no longer live at home. This change entails social, affective, self-esteem, and motivation losses, increasing hopelessness about old age and suffering from chronic diseases and/or disabilities [24]. Among the latter are those caused by injuries to the locomotor system, as most institutionalized older people are below average in terms of lower- and upper-limb muscle strength, which is associated with a low level of physical activity [24]. High physical activity levels have been associated with a greater capacity to generate motor mental images [20], and MI capacity must be trained in older people to obtain positive results [22].

Imagery capacity can be assessed in different ways. Studies on the elderly have pointed out that MI capacity should be carefully assessed, where MI capacity questionnaires and mental chronometry would be very appropriate, among others [25]. Thus, MI can be assessed in terms of vividness through self-reported questionnaires such as the Movement Imagery Questionnaire-3 (MIQ-3) and temporal characteristics through temporal congruency through mental chronometry. Both forms of MI assessment are complementary, as each assesses different aspects of MI.

The MIQ-3 is an instrument validated in Spanish, consisting of 12 items grouped into three subscales. It is a multidimensional measure that has been used to measure the capacity for internal, external, and kinesthetic imagery and whose psychometric properties have shown good internal consistency as well as internal reliability and predictive validity, suggesting that it is a suitable instrument for assessing MI abilities in healthy and young people of both sexes [26,27]. It is important to consider the age of the subject, as it has been shown that the capacity for imagery decreases progressively with age, affecting the development of motor skills [22]. Furthermore, scientific evidence suggests that the MI capacity of some movements is modified due to some age-related alterations, indicating that aging produces selective effects on mental imagery [28]. Nevertheless, the reliability of the MIQ-3 for use in the elderly has not been tested so far, nor have similar questionnaires been validated for use in the elderly. A recent systematic review of MI assessments suggests that more studies are needed in this context, including older populations [29].

On the other hand, temporal congruence is considered the time course of mental operations between simulated and real movements [25]. It is measured through mental chronometry, measuring the time it takes the subject to execute a movement and the time it takes to imagine that movement.

Liu et al. [30] compared MI ability among populations distributed by gender and in three age ranges. They concluded that temporal congruency is preserved with age for simple and usual movements and is impaired for limited and unusual movements. They also observed a lower capacity for internal visual and kinesthetic imagery in people over 60 years of age relative to younger people. Regarding gender, MI ability was found to be better in men than in women. However, some studies have found no significant gender differences in this population [31]. Another study found that women may overestimate the imagined task relative to actual practice, while men underestimate it [32].

Therefore, more studies are needed to support the use of the MIQ-3 and mental chronometry to assess MI ability for these groups of elderly people, paying attention to differences according to age and gender.

This study's main objective was to determine whether the Spanish version of the MIQ-3 is a reliable instrument for measuring motor imagery ability in institutionalized elderly people. The secondary objectives were to explore MI ability as a function of this population's age range, gender, and temporal characteristics (through temporal congruence). As hypotheses, it was established that the Spanish version of the MIQ-3 is a reliable instrument to measure MI capacity in this population and that MI capacity measured by this questionnaire is higher in males than in females and decreases as the age range increases. It is expected that temporal congruency is better preserved in males than in females, and it similarly decreases with age.

#### **2. Materials and Methods**

The design adopted corresponded to reliability studies. A repeated-measures crosssectional design was carried out on the subjects in the sample. In addition, the recommendations established in the Guidelines for Reporting Reliability and Agreement Studies (GRRAS) [33] were followed.

#### *2.1. Participants*

The study sample comprised 60 institutionalized elderly people: 27 men (45%) and 33 women (55%). The 60 subjects were divided into groups according to three age ranges. The first group consisted of 16 people (26.67%) aged between 70 and 79 years (mean (M) = 72.6; standard deviation (SD) = 1.86). The second group consisted of 26 persons (43.33%) aged 80–89 years (M = 84; SD = 1.92), and the third group consisted of 18 persons (30%) aged 90–100 years (M = 92.5; SD = 2.0) (Table 1).

#### **Table 1.** Sociodemographic characteristics of the sample.


*n*, sample size; M, mean; SD, standard deviation.

The inclusion criteria for the study were: Spanish-speaking, aged 70–100 years, of both genders, and without cognitive impairment or dementia as measured by Pfeiffer's Short-Portable Mental State Questionnaire (SPMSQ) [34,35] and Yesavage's Geriatric Depression Scale [36]. The exclusion criteria were having suffered traumatic processes in the last 6 months and being under treatment with central nervous system suppressant drugs. Participants were recruited from the "Residencia de mayores Amavir" social-health center in Torrejón de Ardoz after the center's medical committee granted permission. Participation was voluntary after signing the informed consent form.

#### *2.2. Data Collection Instrument*

The MIQ-3 is composed of 12 items grouped into three subscales (internal visual imagery, external visual imagery, and kinesthetic imagery), which allow for the assessment of MI in both genders about four movements involving knee elevation, jumping, arm movement, and leaning forward at the waist, all repeated in three subscales [26,27]. These movements are described in each statement to be performed under instructions that indicate the initial position, the action, the mental task, and the score using a seven-point Likert scale, indicating the difficulty or ease of "seeing" and "feeling" the movements [26]. It has been validated in different languages and different populations [27].

#### *2.3. Variables*

Gender and age were considered independent and controlled sociodemographic variables in the study. In addition, MI, measured through the MIQ-3, and temporal congruence, measured through mental chronometry, were considered dependent variables. Three movements were performed to measure mental chronometry: elbow flexion-extension, knee flexion-extension, and getting up and sitting down from a chair.

### *2.4. Procedure*

The same researcher oversaw carrying out the two data collection sessions. To homogenize the conditions, the verbal orders given to the subjects during the sessions were standardized before the sessions and carried out in the same room and under the same environmental conditions.

In the first session, the MIQ-3 was administered, and time congruency was measured by mental chronometry of elbow flexion-extension, knee flexion-extension, and getting up and sitting down from a chair. Before performing the mental chronometry task, the experimenter gave a physical demonstration of the movements to be performed. Afterward, using previously standardized commands, they were asked to perform the different movements and then try to imagine them. The execution and imagination times were calculated employing a stopwatch, which was pressed by the researcher at the subjects' "start" and "stop" commands at the moments of both the actual execution of the movements and the imagined execution. Each movement was performed and imagined on three occasions, and each movement's mean mental chronometry value was then calculated.

In the second session (after one week), the MIQ-3 was administered again for the study of retest reliability.

#### *2.5. Statistical Analysis*

Statistical analysis was carried out using SPSS, version 26.0 for Windows (International Business Machines Corporation (IBM), Armonk, NY, USA).

First, the descriptive analysis of the results obtained in the two measurements made with the questionnaire (test and retest) was carried out as well as the mean and the difference between the measurements.

Subsequently, internal consistency was assessed by calculating Cronbach's alpha coefficient. Interpretation was based on the following values: very low (0 to 0.2); low (0.2 to 0.4); moderate (0.4 to 0.6); good (0.6 to 0.8); and high (0.8 to 1). Adequate internal consistency was between 0.7 and 0.939 since excessively high values could indicate redundant items within the questionnaire [37].

The test-retest reliability of each questionnaire item was analyzed by calculating the value of the weighted kappa coefficient, following Cicchetti's method. The weighted kappa coefficient values were interpreted following the classification established by Landis and Koch [38]. Agreement was no agreement if the Kappa index took a value of 0.00; negligible if it was between 0.01 and 0.20; medium if it was between 0.21 and 0.40; moderate between 0.41 and 0.60; substantial between 0.61 and 0.80; and near perfect between 0.81 and 1.00 [39,40]. These analyses were carried out with the statistical program Epidat 4.2. (Consellería de Sanidade, Xunta de Galicia, Spain; Pan American Health Organization (PAHO); CES University, Medellin, Colombia).

The test-retest reliability of each subscale was analyzed by calculating the intraclass correlation coefficient (ICC) using a two-factor model with mixed effects and absolute agreement. The 95% confidence interval for the ICC values was also calculated. The Weir criteria [41] were followed to interpret the ICC values, where values of 0.50 to 0.69 are considered moderate, values of 0.70 to 0.89 as high, and values of 0.90 and above as excellent.

The analysis of differences in MI ability measured by the MIQ-3 was carried out according to sex and age considering that the sample was distributed into three age groups. Two mixed factorial analysis of variances (ANOVAs) were used for this purpose. This

design was used to determine whether the differences analyzed were because of the intersubject factor (either sex or age range). In this sense, in the first mixed factorial analysis of variance (ANOVA), the inter-subject factor was the sex of the subjects, while in the second one, the age range was considered. The hypothesis of interest was the inter-subject factor interaction by time, with an a priori alpha level of 0.05. In addition, the effect size of the observed differences was estimated by calculating the partial eta-squared coefficient (η<sup>p</sup> 2). The assumption of the sphericity hypothesis was tested using Mauchly's test. In those cases where the assumption of sphericity was not met, the Greenhouse–Geisser correction was used. In addition, the analysis was completed by employing multiple comparison tests, using the Bonferroni correction, and determining the effect size, and Cohen's d was calculated.

The data analysis for time congruence was carried out using a mixed factorial ANOVA with respect to sex and age. For differences that conformed to the normal and were homoscedastic, the Mann–Whitney U test was used for those differences that did not conform to the normal, and the effect size was determined by calculating Rosenthal's r with the formula: r = Z/√N [42,43]. Kruskal–Wallis ANOVA was performed for comparison according to age range.

#### **3. Results**

#### *3.1. Descriptive Analysis*

The descriptive analysis of the scores obtained in each subscale of the MIQ-3 showed that in the second session, the values in the three subscales were higher than those obtained in the first session. In this regard, the differences obtained between the means between the two sessions were −2.50 in the external visual subscale, followed by −2.25 in the internal visual subscale and −2.00 in the kinesthetic scale (Table 2).


**Table 2.** Results of the descriptive analysis in each subscale.

IVS, Internal Visual Subscale; EVS, External Visual Subscale; KS, Kinesthetic Subscale; 1st S, first session; 2nd S, second session; CI, confidence interval; SD, standard deviation.

#### *3.2. Analysis of Internal Consistency*

The Cronbach's alpha analysis showed values that allowed us to establish a high internal consistency in the case of the questionnaire. The internal and external visual subscales showed good internal consistency, while the kinesthetic subscale showed moderate consistency (Table 3).

**Table 3.** Results of the analysis of internal consistency and test-retest reliability of Movement Imagery Questionnaire-3 (MIQ-3).



No, item number in MIQ-3; KW, kappa value; CI, confidence interval; *p*, statistical significance; IVS, Internal Visual Subscale; EVS, External Visual Subscale; KS, Kinesthetic Subscale; ICC, intraclass correlation.

#### *3.3. Analysis of the Test-Retest Reliability*

The analysis using the weighted kappa coefficient established that, of the 12 items, 8 showed a medium degree of agreement, 1 item showed a moderate degree of agreement, and 3 items showed substantial agreement (Table 3). The analysis corresponding to the test-retest reliability of each subscale by calculating the ICC made it possible to establish good reliability values (Table 3). These results are confirmed by the visual distributions of the Bland–Altman plots for the test-retest comparison of the three subscales of the MIQ-3 (Figures 1–3).

**Figure 1.** Bland–Altman plot of the internal visual subscale of the MIQ-3.

**Figure 2.** Bland–Altman plot of the external visual subscale of the MIQ-3.

**Figure 3.** Bland–Altman plot of the kinesthetic subscale of the MIQ-3.
