Mental practice of lingual resistance and cortical plasticity in older adults: An exploratory fNIRS study

Purpose: Mental practice using motor imagery (MP) improves motor strength andcoordination in the upper and lower extremities in clinical patient populations. Itseffectiveness as a rehabilitation tool for patients with lingual weakness is not yetwell understood, nor are the underlying mechanisms within the context of swallow orlingual MP. Using previously published data on a lingual and MP exercise program, theobjective of this study was to explore how MP of lingual exercise affects corticalactivation in healthy older adults over time and how neural changes correlate withfunctional oral pressure outcomes. Method: A prospective randomized controlled study waspreviously completed; older healthy participants were randomized to one of fourtreatment groups receiving lingual MP, lingual physical practice, a combination of both,and a sham control. This paper reports descriptive data on cortical activation duringboth the physical and mental forms of lingual resistance in a subgroup of 13participants using functional near-infrared spectroscopy at baseline and after 6 weeksof the assigned exercise regimen. Results: Aggregated data indicates that participantswho completed 6 weeks of lingual exercise, either in physical or in MP form, haddecreased oxygenated hemoglobin when completing a maximal lingual pressure task.Conclusions: Some participants in a lingual resistance MP program demonstrated trendssimilar to those seen after strength training. Combining MP with physical training maylead to greater changes in oxygenation compared to a physical or mental training programalone, although given the small number of participants, it is important not tooverinterpret the results. MP is a promising, innovative approach that may enhancetraditional exercise-based swallowing rehabilitation.