Motor imagery for pain and motor function after spinal cord injury: a systematic review

Imagining motor acts is a cognitive task that engages parts of the executive motor system. While motor imagery has been intensively studied using neuroimaging techniques, most studies lack behavioral observations. Here, we used functional MRI to compare the functional neuroanatomy of motor execution and imagery using a task that objectively assesses imagery performance. With surface electromyographic monitoring within a scanner, 10 healthy subjects performed sequential finger-tapping movements according to visually presented number stimuli in either a movement or an imagery mode of performance. We also examined effects of varied and fixed stimulus types that differ in stimulus dependency of the task. Statistical parametric mapping revealed movement-predominant activity, imagery-predominant activity, and activity common to both movement and imagery modes of performance (movement-and-imagery activity). The movement-predominant activity included the primary sensory and motor areas, parietal operculum, and anterior cerebellum that had little imagery-related activity (-0.1 ~ 0.1%), and the caudal premotor areas and area 5 that had mild-to-moderate imagery-related activity (0.2 ~ 0.7%). Many frontoparietal areas and posterior cerebellum demonstrated movement-and-imagery activity. Imagery-predominant areas included the precentral sulcus at the level of middle frontal gyrus and the posterior superior parietal cortex/precuneus. Moreover, activity of the superior precentral sulcus and intraparietal sulcus areas, predominantly on the left, was associated with accuracy of the imagery task performance. Activity of the inferior precentral sulcus (area 6/44) showed stimulus-type effect particularly for the imagery mode. A time-course analysis of activity suggested a functional gradient, which was characterized by a more "executive" or more "imaginative" property in many areas related to movement and/or imagery. The results from the present study provide new insights into the functional neuroanatomy of motor imagery, including the effects of imagery performance and stimulus-dependency on brain activity.

To benefit from mental practice training after stroke, one must be able to engage in motor imagery, and thus reliable motor imagery assessment tools tailored to persons with sensorimotor impairments are needed. The aims of this study were to (1) examine the test-retest reliability of the Kinesthetic and Visual Imagery Questionnaire (KVIQ-20) and its short version (the KVIQ-10) in healthy subjects and subjects with stroke, (2) investigate the internal consistency of both KVIQ versions, and (3) explore the factorial structure of the two KVIQ versions. The KVIQ assesses on a five-point ordinal scale the clarity of the image (visual: V subscale) and the intensity of the sensations (kinesthetic: K subscale) that the subjects are able to imagine from the first-person perspective. Nineteen persons who had sustained a stroke (CVA group) and 46 healthy persons (CTL group) including an age-matched (aCTL: n = 19) control group were assessed twice by the same examiner 10 to 14 days apart. The test-retest reliability was assessed using intraclass correlation coef- ficients (ICCs). The internal consistency (Cronbach alpha) and the factorial structure of both KVIQ versions were studied in a sample of 131 subjects. In the CVA group, the ICCs ranged from 0.81 to 0.90, from 0.73 to 0.86 in the aCTL group, and from 0.72 to 0.81 in the CTL group. When imagining movements of the affected and unaffected limbs (upper and lower limbs combined) ICCs in the CVA group ranged, respectively, from 0.71 to.87 and from 0.86 to 0.94. Likewise, when imagining movement of the dominant and nondominant limbs, ICCs in the aCTL group ranged, respectively, from 0.75 to 0.89 and from 0.81 to.92. Cronbach a values were, respectively, 0.94 (V) and 0.92 (K) for the KVIQ-20 and 0.89 (V) and 0.87(K) for the KVIQ-10. The factorial analyses indicated that two factors explained 63.4% and 67.7% of total variance, respectively. Both versions of the KVIQ present similar psychometric properties that support their use in healthy individuals and in persons post-stroke. Because the KVIQ-10 can be administered in half the time, however, it is a good choice when assessing persons with physical disabilities.

Background The literature suggests a beneficial effect of motor imagery (MI) if combined with physical practice, but detailed descriptions of MI training session (MITS) elements and temporal parameters are lacking. The aim of this review was to identify the characteristics of a successful MITS and compare these for different disciplines, MI session types, task focus, age, gender and MI modification during intervention. Methods An extended systematic literature search using 24 databases was performed for five disciplines: Education, Medicine, Music, Psychology and Sports. References that described an MI intervention that focused on motor skills, performance or strength improvement were included. Information describing 17 MITS elements was extracted based on the PETTLEP (physical, environment, timing, task, learning, emotion, perspective) approach. Seven elements describing the MITS temporal parameters were calculated: study duration, intervention duration, MITS duration, total MITS count, MITS per week, MI trials per MITS and total MI training time. Results Both independent reviewers found 96% congruity, which was tested on a random sample of 20% of all references. After selection, 133 studies reporting 141 MI interventions were included. The locations of the MITS and position of the participants during MI were task-specific. Participants received acoustic detailed MI instructions, which were mostly standardised and live. During MI practice, participants kept their eyes closed. MI training was performed from an internal perspective with a kinaesthetic mode. Changes in MI content, duration and dosage were reported in 31 MI interventions. Familiarisation sessions before the start of the MI intervention were mentioned in 17 reports. MI interventions focused with decreasing relevance on motor-, cognitive- and strength-focused tasks. Average study intervention lasted 34 days, with participants practicing MI on average three times per week for 17 minutes, with 34 MI trials. Average total MI time was 178 minutes including 13 MITS. Reporting rate varied between 25.5% and 95.5%. Conclusions MITS elements of successful interventions were individual, supervised and non-directed sessions, added after physical practice. Successful design characteristics were dominant in the Psychology literature, in interventions focusing on motor and strength-related tasks, in interventions with participants aged 20 to 29 years old, and in MI interventions including participants of both genders. Systematic searching of the MI literature was constrained by the lack of a defined MeSH term.