Gravitational insecurity: A brief introduction to a condition of life-long balance challenges identified by occupational therapists

Abstract

Background: Gravitational insecurity, first identified by A. Jean Ayres, is a condition of life-long problems with balance and movement that impact ADLs in children and adults and, as recently found, increase fall risk. This condition presents with different sets of salient co-morbidities in children and adults. Understanding of vestibular and other pathophysiological changes underlying gravitational insecurity is increasing but is still incomplete. Treatment options are effective for some clients but need to be expanded.

Methodology: This narrative review of the literature describes the presentation, prevalence and co-morbidities of GrI in children and adults based on published reports. An explanation of the likely pathophysiological causes of GrI is based on the results of collaborative neuroscientific/OT research and presented in the context of the relevant vestibular system anatomy and physiology. The rationale for important future studies of this pathophysiology is explained. Review of the current literature on vestibular rehabilitation suggests a possible new treatment modality for GrI.

Findings: Children with gravitational insecurity comprise up to 5% of clients seen by many pediatric OTs. About 2% of American adolescents and adults experience full blown gravitational insecurity while another 17% have milder balance issues. Fine and gross motor difficulties and sensory hypersensitivities are common co-morbidities in children and adults, respectively. A pathophysiological cause of gravitational insecurity may be deficiencies in a “vestibular velocity storage” circuit in the brainstem which inadequately amplifies and prolongs signals of small, slow head rotations from the semi-circular canals that are necessary for balance. Such deficiencies may be partially compensated by a greater reliance on neck muscle proprioception for determining head tilt. Galvanic vestibular stimulation is an easy to apply, non-invasive treatment that has improved balance and/or gait in healthy older adults and in patients with various neurological conditions. It is likely to help people with gravitational insecurity. Gravitational insecurity is a real condition of life-long balance problems that remains unrecognized by the larger health provider community.

Conclusions and recommendations: Considerable progress in understanding the characteristics and pathophysiological bases of GrI has been made through neuroscientific/OT collaborations. Gravitational insecurity results from deficiencies in vestibular function that undercut balance and create sensitivities to movement. This understanding can be broadened by further population-based research into the prevalence and characteristics of GrI in additional countries and by categorizing the heterogeneity of GrI presentation. Understanding can be deepened by research that assesses the relationship of tilt intolerance to VVS anomalies and measures otolith organ thresholds for head tilt. Clinically, the promising therapeutic possibilities of galvanic vestibular stimulation for GrI should be tried. Acquisition of such knowledge and development of such practice can open the door to informing the larger health provider community about gravitational insecurity, much to the credit of OTs who originally identified, and continue to treat, this curious condition.