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Cuenca-Martínez et al. | Journal of Clinical and Translational Research 2024; 10(1): 52-61 53
but quantitatively less than, the action actually being performed [3]. Physical training has been widely used in respiratory
Regarding the neurophysiology behind these neurosensory-motor rehabilitation. In fact, some systematic reviews have shown
training tools, there appears to be an overlap in the activity of some that respiratory muscle training improves several pulmonary
brain areas during MI, AO, and actual performance [4]. Hardwick function parameters and maximal static pressures in some clinical
et al. [4] found that MI and AO training recruited similar premotor- populations such as patients with chronic obstructive pulmonary
parietal cortical networks but, while MI recruited a subcortical disease [26], lung cancer survivors [27], asthma [28], obstructive
network similar to that found during actual movement execution, sleep apnea [29], or tobacco smokers [30,31]. Therefore, we
AO training showed no activity in any subcortical area. believe that the addition of mental practice along with the
In addition, AO training and MI generation processes can be performance of respiratory muscle training could have an
carried out in different modalities. Both methods of movement impact on these clinical populations. However, it is too early to
representation can be implemented in two perspectives. First, be certain of this statement. To date, we believe that there is no
there is the first-person perspective, where the person observes study that has evaluated the effect of MI and AO on pulmonary
or imagines him/herself showing his/her own point of view. function parameters and maximal static pressures. There are a
On the other hand, based on the third-person perspective, the few studies that have evaluated the effect of MI on breath-holding
person observes or imagines him/herself from the outside, as an performance [32,33]. Therefore, we set out the following pilot
external observer. Both forms have been described and studied study with the aim to evaluate the effect of MI and AO training in
in the scientific literature [5-11]. In addition to the first-person isolation to see if it had any impact on maximal static respiratory
or third-person perspective, also called internal or external pressures and several pulmonary function parameters. The
perspective, respectively, MI is specifically subclassified into two authors hypothesize that mental practice in isolation may have a
other modalities, namely visual MI and kinesthetic MI [12,13]. significant impact on these variables and in future studies, it could
Theoretically, the differences between these two modalities of be combined with respiratory muscle training to see if it increases
construction and generation of MI lie in their execution. On the its clinical effect.
one hand, in kinesthetic MI, the ability to feel is incorporated Because there are currently no studies that aim to assess the
at the same time as the MI task is performed, causing, at the impact of movement representation techniques in isolation on
neurophysiological level, some differences with respect to pulmonary function, the main aim of this pilot study was to assess
visual MI [14]. For example, during kinesthetic MI, there is a the effects of MI and AO in isolation on respiratory function in
greater increase in electromyographic activity than in the visual mild smokers.
modality [15]. These findings were also found in the stimulation
of the corticospinal system evaluated by neuroimaging [16]. Even 2. Methods
at the level of neurovegetative system activity, the kinesthetic 2.1. Study design
modality has also been found to elicit higher levels of heart rate,
respiratory rate, skin conductance, etc. [17,18]. Visual MI refers to This study was a randomized, single-blind, placebo-controlled
creating a motor image being, therefore, a representation devoid pilot trial, which was planned and conducted in accordance
of any stimulation of the somatosensory system [12,14]. with Consolidated Standards of Reporting Trials (CONSORT)
Interest in the study of the effects of MI and AO training on requirements and was approved by The Ethics Committee of
some sensorimotor variables has grown in recent years. For Research in Humans of the Ethics Commission in Experimental
example, Cuenca-Martínez et al. [19] found that adding MI to Research of University of Valencia (number: 2301127). This study
an usual treatment improved active range of motion in patients was registered in the United States Randomized Trials Registry
subjected to immobilization. Furthermore, they also showed on clinicaltrial.gov (trial registry number: NCT05662072). All
that MI maintained significantly greater strength and speed the participants were briefed on the study procedures, which
in patients undergoing surgery [19]. In addition to this, it has were planned according to the ethical standards of the Helsinki
been found that adding MI to an usual treatment improved pain Declaration.
intensity and strength to a greater degree than usual treatment 2.2. Participants
alone in patients undergoing a total knee arthroplasty [20]. Both
techniques have been shown to improve the motor learning All data were collected at the University of Valencia (between
process both in isolation [21,22] and in combination with physical November 2022 and February 2023) by email and social networks.
exercise [23]. Losana-Ferrer et al. [24] found that both AO and All participants were currently smokers aged >18 years and had a
MI, in combination with actual practice, elicited higher levels pack per year index of <5 (mild smoking index). This population
of strength as well as electromyographic activity than physical was chosen because we were looking for a population as close as
practice in isolation. This increase in strength has also been found possible to healthy subjects but with room for improvement in
when AO and MI training were combined in isolation, without the the assessment tests. This study excluded those who presented a
presence of actual practice [25]. It seems therefore that MI and respiratory pathology, cardiac, systematic (hypertension, diabetes,
AO training, both in isolation and in combination with physical viral infections, etc.), or metabolic disease, history of recent
practice, leads to improvements in some clinical variables of surgery (in the last year), vertebral fracture, or osteoarticular
interest. disorders of the spine area.
DOI: http://doi.org/10.36922/jctr.00117