Foot and Ankle Somatosensory Deficits Affect Balance and Motor Function in Children With Cerebral Palsy

Anastasia Zarkou; Samuel C K Lee; Laura A Prosser; John J Jeka

doi:10.3389/fnhum.2020.00045

Foot and Ankle Somatosensory Deficits Affect Balance and Motor Function in Children With Cerebral Palsy

Front Hum Neurosci. 2020 Feb 26:14:45. doi: 10.3389/fnhum.2020.00045. eCollection 2020.

Authors

Anastasia Zarkou¹, Samuel C K Lee^{2

3}, Laura A Prosser⁴, John J Jeka⁵

Affiliations

¹ Spinal Cord Injury Research Laboratory, Crawford Research Institute, Shepherd Center, Atlanta, GA, United States.
² Department of Physical Therapy and Interdisciplinary Graduate Program in Biomechanics and Movement Science, University of Delaware, Newark, DE, United States.
³ Research Department, Shriners Hospital for Children, Philadelphia, PA, United States.
⁴ Department of Pediatrics, University of Pennsylvania & The Children's Hospital of Philadelphia, Philadelphia, PA, United States.
⁵ Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States.

Abstract

Sensory dysfunction is prevalent in cerebral palsy (CP). Evidence suggests that sensory deficits can contribute to manual ability impairments in children with CP, yet it is still unclear how they contribute to balance and motor performance. Therefore, the objective of this study was to investigate the relationship between lower extremity (LE) somatosensation and functional performance in children with CP. Ten participants with spastic diplegia (Gross Motor Function Classification Scale: I-III) and who were able to stand independently completed the study. Threshold of light touch pressure, two-point discriminatory ability of the plantar side of the foot, duration of cutaneous vibration sensation, and error in the joint position sense of the ankle were assessed to quantify somatosensory function. The balance was tested by the Balance Evaluation System Test (BESTest) and postural sway measures during a standing task. Motor performance was evaluated by using a battery of clinical assessments: (1) Gross Motor Function Measure (GMFM-66-IS) to test gross motor ability; (2) spatiotemporal gait characteristics (velocity, step length) to evaluate walking ability; (3) Timed Up and Go (TUG) and 6 Min Walk (6MWT) tests to assess functional mobility; and (4) an isokinetic dynamometer was used to test the Maximum Volitional Isometric Contraction (MVIC) of the plantar flexor muscles. The results showed that the light touch pressure measure was strongly associated only with the 6MWT. Vibration and two-point discrimination were strongly related to balance performance. Further, the vibration sensation of the first metatarsal head demonstrated a significantly strong relationship with motor performance as measured by GMFM-66-IS, spatiotemporal gait parameters, TUG, and ankle plantar flexors strength test. The joint position sense of the ankle was only related to one subdomain of the BESTest (Postural Responses). This study provides preliminary evidence that LE sensory deficits can possibly contribute to the pronounced balance and motor impairments in CP. The findings emphasize the importance of developing a thorough LE sensory test battery that can guide traditional treatment protocols toward a more holistic therapeutic approach by combining both motor and sensory rehabilitative strategies to improve motor function in CP.

Keywords: balance; cerebral palsy; motor function; postural control; sensory function; somatosensation.