Developing Proprioceptive Countermeasures to Mitigate Postural and Locomotor Control Deficits After Long-Duration Spaceflight

Astronauts experience post-flight disturbances in postural and locomotor control due to sensorimotor adaptations during spaceflight. These alterations may have adverse consequences if a rapid egress is required after landing. Although current exercise protocols can effectively mitigate cardiovascular and muscular deconditioning, the benefits to post-flight sensorimotor dysfunction are limited. Furthermore, some exercise capabilities like treadmill running are currently not feasible on exploration spaceflight vehicles. Thus, new in-flight operational countermeasures are needed to mitigate postural and locomotor control deficits after exploration missions. Data from spaceflight and from analog studies collectively suggest that body unloading decreases the utilization of proprioceptive input, and this adaptation strongly contributes to balance dysfunction after spaceflight. For example, on return to Earth, an astronaut’s vestibular input may be compromised by adaptation to microgravity, but their proprioceptive input is compromised by body unloading. Since proprioceptive and tactile input are important for maintaining postural control, keeping these systems tuned to respond to upright balance challenges during flight may improve functional task performance after flight through dynamic reweighting of sensory input. Novel approaches are needed to compensate for the challenges of balance training in microgravity and must be tested in a body unloading environment such as head down bed rest. Here, we review insights from the literature and provide observations from our laboratory that could inform the development of an in-flight proprioceptive countermeasure.

Proprioception Impairment and Treatment Approaches in Pediatrics

In children problems like trauma and injuries are quite obvious. Other problems related to sensory system dysfunction are identified at the later stages of the child due to lack of awareness of the sensory integration problems which is not obvious. Some children have behavioral problems and some are poor at the school which is related to each other finally cause trouble to perform their daily routine. Early identification and intervention play a major role in improving the ability and development of the proprioceptive senses. Hence this chapter will introduce the new aspect of proprioception sense and its dysfunction. It would enhance you to identify the problems and understand the challenges that the child come across due to increase or decrease in proprioceptive input. We will be able to help them to overcome these challenges and frame a treatment strategy and help them to lead a successful life.

A static sound source can improve postural stability during walking

BACKGROUND: During walking, postural stability is controlled by visual, vestibular and proprioceptive input. The auditory system uses acoustic input to localize sound sources. For some static balance conditions, the auditory influence on posture was already proven. Little is known about the impact of auditory inputs on balance in dynamic conditions. OBJECTIVE: This study is aimed at investigating postural stability of walking tasks in silence and sound on condition to better understand the impact of auditory input on balance in movement. METHODS: Thirty participants performed: walking (eyes open), tandem steps, walking with turning head and walking over barriers. During each task, acoustic condition changed between silence and presented noise through an earth-fixed loudspeaker located at the end of the walking distance. Body sway velocity was recorded close to the body’s center of gravity. RESULTS: A decreased body sway velocity was significant for walking (eyes open), tandem steps and walking over barriers when noise was presented. Those auditory stimuli did not affect sway velocity while walking with turning head. The posture has probably improved due to the localization ability when walking with the head facing forward, while the localization ability was impaired when turning the head. CONCLUSIONS: The localization ability of a fixed sound source through the auditory system has a significant but limited impact on posture while walking.

Spinal neuronal dysfunction after deprivation of supraspinal input

A central nervous system lesion can lead to remote structural and functional changes which may limit functional recovery. For example, after a spinal cord injury (SCI) structural and functional alterations of spinal neuronal networks take place: in the first weeks after an SCI, neither locomotor nor spinal reflex (SR) activity can be evoked. Once spinal shock has resolved, an early SR component can be re-evoked and locomotor electromyography (EMG) activity re-appears when appropriate proprioceptive input is provided. In a more chronic stage of SCI alterations in SR components are accompanied by a decline of EMG amplitude in the leg muscles during assisted locomotion. According to rodent experiments it is assumed that the deprivation of supraspinal input and the lack of meaningful proprioceptive input to spinal neuronal networks account for such alterations. A critical combination of sensory cues through physiological training strategies might prevent the development of an undirected neural plasticity.

Botulinum Toxin Effects on Sensorimotor Integration in Focal Dystonias

(1) Background: In dystonia, the somatosensory temporal discrimination threshold (STDT) is abnormally increased at rest and higher and longer-lasting during movement execution in comparison with healthy subjects (HS), suggesting an abnormal sensorimotor integration. These abnormalities are thought to depend on abnormal proprioceptive input coming from dystonic muscles. Since Botulinum toxin-A (BT-A) reduces proprioceptive input in the injected muscles, our study investigated the effects of BT-A on STDT tested at rest and during voluntary movement execution in patients with focal dystonia. (2) Methods: We enrolled 35 patients with focal dystonia: 14 patients with cervical dystonia (CD), 11 patients with blepharospasm (BSP), and 10 patients with focal hand dystonia (FHD); and 12 age-matched HS. STDT tested by delivering paired stimuli was measured in all subjects at rest and during index finger abductions. (3) Results: Patients with dystonia had higher STDT values at rest and during movement execution than HS. While BT-A did not modify STDT at rest, it reduced the abnormal values of STDT during movement in CD and FHD patients, but not in BSP patients. (4) Conclusions: BT-A improved abnormal sensorimotor integration in CD and FHD, most likely by decreasing the overflow of proprioceptive signaling from muscle dystonic activity to the thalamus.

Applying Osteopathic Manipulative Treatment to Postconcussion Syndrome: A Case Report

Concussions are a form of mild traumatic brain injury, which are caused by trauma to the head or body. Symptoms of concussion can include headaches, dizziness, imbalance, and difficulty with concentration, which can persist for weeks, months, or even years after the event. This case report details the treatment of a 17-year-old girl suffering from postconcussion symptoms, which prevented her from full participation in school for 2 months after the injury. The patient’s symptoms greatly improved with the application of osteopathic manipulative treatment (OMT). Treatment focused on balancing and restoring proper proprioceptive input, addressing musculoskeletal restrictions, and improving circulatory and lymphatic flow. Posttreatment, the patient was able to return to full activities at school. This case demonstrates the positive effect of integrating OMT into a case of postconcussion syndrome.

Cervicogenic dizziness

Cervical muscles have numerous connections with vestibular, visual and higher centres, and their interactions can produce effective proprioceptive input. Dysfunction of the cervical proprioception because of various neck problems can alter orientation in space and cause a sensation of disequilibrium. Cervicogenic dizziness (CGD) is a clinical syndrome characterized by the presence of dizziness and associated neck pain in patients with cervical pathology. Here, we report a 24-year-old female, who was diagnosed with CGD based on the correlating episodes of neck pain and dizziness. Both symptoms improved with targeted chiropractic adjustment and ultrasound therapy. CGD is a seemingly simple complaint for patients, but tends to be a controversial diagnosis because there are no specific tests to confirm its causality. For CGD to be considered, an appropriate management for the neck pain should not be denied any patient.

The disappearing hand: vestibular stimulation does not improve hand localisation

Background Bodily self-consciousness depends on the coherent integration of sensory information. In addition to visual and somatosensory information processing, vestibular contributions have been proposed and investigated. Vestibular information seems especially important for self-location, but remains difficult to study. Methods This randomised controlled experiment used the MIRAGE multisensory illusion box to induce a conflict between the visually- and proprioceptively-encoded position of one hand. Over time, the perceived location of the hand slowly shifts, due to the fact that proprioceptive input is progressively weighted more heavily than the visual input. We hypothesised that left cold caloric vestibular stimulation (CVS) augments this shift in hand localisation. Results The results from 24 healthy participants do not support our hypothesis: CVS had no effect on the estimations with which the perceived position of the hand shifted from the visually- to the proprioceptively-encoded position. Participants were more likely to report that their hand was ‘no longer there’ after CVS. Taken together, neither the physical nor the subjective data provide evidence for vestibular enhanced self-location.