Research Roundup: May 2021
May 28, 2021
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Age-Related Reduction in Motor Adaptation
Wolpe N, Ingram J, Tsvetanov K, et al. (2020). Age-related reduction in motor adaptation: brain structural correlates and the role of explicit memory. Neurobiology of Aging 90: 13-23.
The authors of this study examined the differences in the brain structure and cognition underlying motor adaptation in a population-based cohort. Results support the hypothesis that sensorimotor adaptation is a composite of multiple learning strategies, which are differentially affected by age, and the authors conclude that "that across the lifespan, motor adaptation declines with age as a result of the deteriorating explicit learning system".
Key Points: Motor Adaptation and Age Related Changes
- Adaptation of movement to environmental changes varies across the lifespan.
- Motor adaptation is related to individual differences in visuospatial working memory.
- The degree of motor adaptation is typically reduced with age,1 although visuomotor adaptation does not necessarily change with age.2
- In the classical interpretation of sensorimotor adaptation, an internal forward model predicts the sensory outcome of one’s movement.
- Updating of the internal forward model is made possible by a discrepancy between the sensorimotor prediction and sensory feedback.
- The medial temporal lobe and hippocampus contribute to motor adaptation. The degree of motor adaptation is related to changes in mean diffusivity of white matter within the medial temporal lobe.
- This implies that young healthy individuals who show increased white matter integrity can adapt more in a visuomotor learning task.
- The hippocampus contributes to the acquisition of motor sequences via connections with higher cortical regions, and may be essential for consolidating motor memories via their interactions with the cerebellum and striatum.
- There is evidence that implicit motor adaptation is preserved in older age, while explicit adaptation deteriorates:
- When an experimental visual perturbation is small and gradual, emphasizing implicit processes, older adults adapt their movement as well as younger adults.3
- When young and old participants are matched by explicit knowledge of the perturbation, age-related differences largely dissipate.4
- Recently, there has been a dissociation between the contribution of implicit and explicit learning to age-related decline in motor adaptation.5
- Age-related reduction in grey matter volume in the bilateral premotor and lateral prefrontal cortex is related to reduced adaptation.
- These clusters overlap with regions that have been suggested to mediate spatial working memory capacity, which is important for motor adaptation.
- In humans, striatal activation has been demonstrated during a motor adaption task,6 and is implicated in tasks involving motor sequence learning.
- The striatum and basal ganglia complement sensory prediction error-based learning by reinforcing movements that lead to rewarding outcomes, thus contributing to overall adaptation.
- It is this learning strategy that is impaired in older age.
- The sensorimotor system is capable of adapting to external changes that occur in the environment as well as internal changes in neuronal and musculoskeletal dynamics.
- This adaptive ability of the sensorimotor system is critical for learning new skills and also adjusting to previously learned movements when presented with new tasks.
- Effects of age on motor adaption are explained by the optimal control theory, which proposes that the central nervous system continuously stimulates an individual’s interaction with the environment during the execution of a voluntary movement.
- The decline in motor adaptation with age is independent of implicit learning and results from deterioration in explicit learning processes.
- The reduction in motor adaptation with age is tightly coupled with the reduction in explicit learning.
- However, age may not affect cerebellar-based learning mechanisms despite a degree of cerebellar degeneration.
- Researchers found that reduction in grey matter volume in the prefrontal cortex and striatum - but not in the cerebellum - was related to adaptation differences with age.
- Differences in the medial temporal lobe, including the hippocampus, were also strongly associated with motor adaptation with age.
- The anterior hippocampus supports the learning of new environmental layouts.
- The medial temporal and anterior hippocampus contribute to the consolidation of motor memories by encoding performance error signals that are critical for the explicit component of motor adaptation.
- This degeneration with age makes older people prone to motor learning deficits.
- Motor adaptation is more positively related to long-term memory scores with age.
- However, motor adaptation relates to short-term memory measures regardless of age.
Clinically: Pilates in Practice
- Consider age when designing rehabilitation programs - at what stage of the lifespan is your client, and how does this affect their explicit learning systems?
- Conscious problem-solving (explicit learning) becomes more difficult with age, therefore look to provide more sensory input for learning feedback:
- Closed kinetic chain exercises.
- Joint approximation for proprioception.
- Visualizations and imagery.
- Verbal and tactile cueing.
1. King, B.R., Fogel, S.M., Albouy, G., Doyon, J., 2013. Neural correlates of the age-related changes in motor sequence learning and motor adaptation in older adults. Front. Hum. Neurosci. 7, 142.
2. Heuer, H., Hegele, M., 2008a. Adaptation to direction-dependent visuo-motor rotations and its decay in younger and older adults. Acta Psychol. (Amst) 127, 369e381.
3. Buch, E.R., Young, S., Contreras-Vidal, J.L., 2003. Visuomotor adaptation in normal aging. Learn Mem. 10, 55e63
4. Heuer, H., Hegele, M., 2008b. Adaptation to visuomotor rotations in younger and older adults. Psychol. Aging 23, 190e202.
5. Vandevoorde, K., Orban de Xivry, J.-J., 2019. Internal model recalibration does not deteriorate with age while motor adaptation does. Neurobiol. Aging 80,138e153
6. Seidler, R.D., Noll, D.C., Chintalapati, P., 2006. Bilateral basal ganglia activation associated with sensorimotor adaptation. Exp. Brain Res. 175, 544e555
Kiss ‘Goodbye’ to the Kissing Knees
Agnethe Nilstad, Erich Petushek, Kam-Ming Mok, Roald Bahr & Tron Krosshaug (2021): Kiss goodbye to the ‘kissing knees’: no association between frontal plane inward knee motion and risk of future non-contact ACL injury in elite female athletes, Sports Biomechanics, DOI: 10.1080/14763141.2021.1903541
The authors of this prospective cohort study hypothesized that greater frontal plane projection angles, medial knee displacement and lateral pelvic tilt, as well as greater leg asymmetry, would be associated with increased risk of ACL injury.
The study found no association between frontal plane hip and knee kinematics in single-leg squats or vertical drop jumps with overhead target and ACL injury risk in elite athletes.
- The long-term consequences of ACL injury can be severe, with a high risk of early osteoarthritis, pain, and reduced knee function.
- Excessive knee valgus motion seems to be a consistent feature of non-contact ACL injury situations, thus making it necessary to assess frontal plane hip and knee motion in different movement tasks.
- A screening test serves an important role in identifying potential risk factors related to movement characteristics.
- Two-dimensional analysis assessing frontal plane projection angle represents a valid and reliable method to quantify knee-valgus motion during screening tasks (such as drop jump landings, single-leg landings, single-leg squats, side-steps, and side jump manoeuvres).
- Although 3D analysis is the gold standard research tool, surface markers can introduce significant errors in valgus measurements due to landmark identification and soft tissue artefacts.
- A previous systematic review of evidence concluded that frontal plane kinematics cannot be used to screen for ACL injury risk.1
- A single leg squat test can detect poor knee control in athletes who demonstrate good control during a vertical drop jump test.
- However, results from this study shoe that a single-leg test cannot detect injury-related movement characteristics.
- Previous studies show that single-leg drop jumps are better suited to detect movement-related risk factors for non-contact ACL injuries.2
- A one-leg drop jump may be a more appropriate task than two-leg drop jumps or single-leg squats to identify injury-related movement characteristics.
Clinically: Pilates in Practice
- Most Pilates exercises are performed in a slow and controlled manner, but it is important to assess and support dynamic movements as they relate to functional task requirements.
- This includes ensuring that movements are practiced in an upright position, to train movement loads against gravity.
- Begin to use the Jumpboard to assess and practice double leg and single leg landing biomechanics: progress to alternating leg "hops"/jumping.
- Side lying jumping with the Footbar or Jumpboard on the Reformer is useful to strengthen alignment in the frontal plane (work to "un-kiss" those knees!).
- Progress to upright jumping/hopping/running tasks.
1. Cronström, A., Creaby, M. W., & Ageberg, E. (2020, August 20). Do knee abduction kinematics and kinetics predict future anterior cruciate ligament injury risk? A systematic review and meta-analysis of prospective studies. BMC Musculoskeletal Disorders, 21(1), 563. PMID: 32819327; PMCID: PMC7441716. https://doi.org/10.1186/s12891-020-03552-3
2. Numata, H., Nakase, J., Kitaoka, K., Shima, Y., Oshima, T., Takata, Y., Shimozaki, K., & Tsuchiya, H. (2018). Two-dimensional motion analysis of dynamic knee valgus identifies female high school athletes at risk of non-contact anterior cruciate ligament injury. Knee Surgery, Sports Traumatology, Arthroscopy: Official Journal of the ESSKA, 26(2), 442–447. https://doi. org/10.1007/s00167-017-4681-9
Radiographic Femoroacetabular Impingement Morphology in Adolescent Spine Patients
Nabi, Vugar, Halil Demirkiran, Bulent Atilla, Mazhar Tokgozoglu, and Omur Caglar. "The prevalence of radiographic femoroacetabular impingement morphology in adolescent spine patients." Medicine Science | International Medical Journal 10, no. 2 (2021), 524. doi:10.5455/medscience.2021.04.108
This study compared spinopelvic parameters in asymptomatic scoliosis and asymptomatic patients with radiographic evidence of femoroacetabular impingement.
230 hips of 115 patients with adolescent idiopathic scoliosis were evaluated in this study, with radiographic images analysed for anteroposterior alpha angle, center-edge angle, Tonnis angle, crossover sign, lumbar lordosis, sacral slope, pelvic tilt, pelvic incidence, coxa profunda, and ischial spine sign.
Results from this study suggest that there is a significant association between between spinal deformity and the presence of femoroacetabular impingement morphology. However, there was no relationship between femoroacetabular impingement morphology and spinopelvic parameters.
Radiographic measurements related to femoracetabular impingement morphology (Nabi et al, 2021); a) Radiograph showing an example of alpha angle measurement on Antero-posterior pelvic imaging. b) Tonnis angle. c) Measurement of LCEA. d) Crossover sign and Ischial spine sign evaluation. e) The assessment of coxa profunda. f) The evaluation of spinopelvic parameters
- Abnormal morphology or biomechanics in the pelvis or spine inherently affect each other by way of the lumbosacral junction.
- Changes in spinal alignment alter hip biomechanics and may also predispose an individual to hip pathologies.
- Sagittal balance about the lumbo-sacral pelvic junction plays an important role in hip disorders.
- Changes in pelvic tilt alter acetabular coverage in terms of lateral centre-edge angle, acetabular crossover, or Tonnis angle.
- Femoroacetabular impingement is a potential cause of acetabular chondrolabral damage as well as a causative factor in the development of osteoarthritis.
- In this study, hips with signs of femoracetabular impingement showed a higher alpha angle (p=0.001), Tonnis angle (p=0.001), centre-edge angle, cross-over sign, coxa profunda, and ischial spine sign (p=0.001).
Clinically: Pilates in Practice
- Femoral, sacropelvic, and lumbar spine movements cannot be decoupled: observe for subtle changes in alignment and assess how these impact dissociated and functional movements.
- Pelvic Clocks, Pelvic Press, Bent Knee Fall Outs, Mermaid Prep, and Side to Side are good pre-Pilates exercises to use as movement assessments for hip/pelvis/lumbar pathologies.