NCS Assessments of the Motor, Sensory, and Physical Health Domains

As part of the National Children's Study (NCS) comprehensive and longitudinal assessment of the health status of the whole child, scientific teams were convened to recommend assessment measures for the NCS. This manuscript documents the work of three scientific teams who focused on the motor, sensory, or the physical health aspects of this assessment. Each domain team offered a value proposition for the importance of their domain to the health outcomes of the developing infant and child. Constructs within each domain were identified and measures of these constructs proposed. Where available extant assessments were identified. Those constructs that were in need of revised or new assessment instruments were identified and described. Recommendations also were made for the age when the assessments should take place.

Vestibular Rehabilitation for Children

This article focuses on vestibular rehabilitation (VR) for children. Reports of the presence of vestibular dysfunction in infants, young children, and adolescents have increased over the past decade. In addition to being a comorbidity of sensorineural hearing loss, vestibular dysfunction has been noted in children with cytomegalovirus, late prematurity, and concussion, to name a few. Despite ample evidence and reports of VR for adults, the selection and provision of exercises to be included in the VR protocol for children vary, depending on the nature of the lesion, impairments identified, age at the time of lesion, and developmental factors such as critical periods of development and intermodality interdependence. Unlike adults, children with loss of function or hypofunction of the vestibular apparatus since or shortly after birth present with a developmental delay that is progressive. Very young children may not be able to describe symptoms but rather only avoid activities or cry. This report provides a review of vestibular-related impairments in children, determinants of the symptoms and functional impairments of vestibular dysfunction, the mechanisms of recovery in children, the challenges of VR for children, and a summary of research on the efficacy for VR for children.

Normative Scores for the NIH Toolbox Dynamic Visual Acuity Test from 3 to 85 Years

As part of the National Institutes of Health Toolbox initiative, a computerized test of dynamic visual acuity (cDVA) was developed and validated as an easy-to-administer, cost- and time-efficient test of vestibular and visual function. To establish normative reference values, 3,992 individuals, aged 3–85 years, without vestibular pathology underwent cDVA testing at multiple clinical research testing facilities across the United States. Test scores were stratified by sociodemographic characteristics. cDVA was worse in males (p < 0.001) and those subjects 50 years or older, while there was no difference in dynamic visual acuity across age groups binned from 3 to 49 years. Furthermore, we used these normative cDVA data as a criterion reference to compare both the long (validated) and short versions of the test. Both versions can distinguish between those with and without vestibular pathology (p = 0.0002 long; p = 0.0025 short). The intraclass correlation coefficient between long- and short-cDVA tests was 0.86.

Motor assessment using the NIH Toolbox

Motor function involves complex physiologic processes and requires the integration of multiple systems, including neuromuscular, musculoskeletal, and cardiopulmonary, and neural motor and sensory-perceptual systems. Motor-functional status is indicative of current physical health status, burden of disease, and long-term health outcomes, and is integrally related to daily functioning and quality of life. Given its importance to overall neurologic health and function, motor function was identified as a key domain for inclusion in the NIH Toolbox for Assessment of Neurological and Behavioral Function (NIH Toolbox). We engaged in a 3-stage developmental process to: 1) identify key subdomains and candidate measures for inclusion in the NIH Toolbox, 2) pretest candidate measures for feasibility across the age span of people aged 3 to 85 years, and 3) validate candidate measures against criterion measures in a sample of healthy individuals aged 3 to 85 years (n = 340). Based on extensive literature review and input from content experts, the 5 subdomains of dexterity, strength, balance, locomotion, and endurance were recommended for inclusion in the NIH Toolbox motor battery. Based on our validation testing, valid and reliable measures that are simultaneously low-cost and portable have been recommended to assess each subdomain, including the 9-hole peg board for dexterity, grip dynamometry for upper-extremity strength, standing balance test, 4-m walk test for gait speed, and a 2-minute walk test for endurance.

New portable tool to screen vestibular and visual function--National Institutes of Health Toolbox initiative

As part of the National Institutes of Health Toolbox initiative, we developed a low-cost, easy-to-administer, and time-efficient test of vestibular and visual function. A computerized test of dynamic visual acuity (cDVA) was used to measure the difference in visual acuity between head still and moving in yaw. Participants included 318 individuals, aged 3 to 85 years (301 without and 17 with vestibular pathology). Adults used Early Treatment of Diabetic Retinopathy Study (ETDRS) optotypes; children used ETDRS, Lea, and HOTV optotypes. Bithermal calorics, rotational chair, and light box testing were used to validate the cDVA. Analysis revealed that the cDVA test is reliable for static (intraclass correlation coefficient [ICC] >/= 0.64) and dynamic (ICC >/= 0.43-0.75) visual acuity. Children younger than 6 years old were more likely to complete cDVA with Lea optotypes, but reliability and correlation with ETDRS was better using HOTV optotypes. The high correlation between static acuity and light box test scores (r = 0.795), significant difference of cDVA scores between those with and without pathology (p </= 0.04), and the good to excellent sensitivity (73%) and specificity (69%) establish that the cDVA is a valid and reliable measure of visual acuity when the head is still and moving, as well as a good proxy of vestibular function to yaw rotation.

Preliminary evidence of improved gaze stability following exercise in two children with vestibular hypofunction

Despite impaired gaze stability and reading in children with sensorineural hearing loss (SNHL) and vestibular hypofunction (VH), there are no reports of intervention. We examined the effect of visual-vestibular exercises in two children on dynamic visual acuity (DVA), critical print size (CPS) and reading acuity (RA) using an ABA design. Improvement in CPS and RA was seen in both subjects. DVA improved only in the subject with acquired versus congenital VH. These results suggest that although exercise improves reading acuity, age at the time of lesion affects the improvement of DVA in children with SNHL and BVH.

Evidence that vestibular hypofunction affects reading acuity in children

OBJECTIVE

Despite reported gaze stability deficits in children with hearing impairment and concurrent vestibular hypofunction, the reading difficulties reported in this population have not been linked to the gaze instability. The purpose of this study was to develop a modified version of the MNREAD chart that enabled responses orally or using sign language.

METHODS

Seventy-two typically developing children and 14 children with sensorineural hearing loss with and without vestibular hypofunction participated. We examined: (1) reliability and age related changes in reading acuity scores, (2) the effect of vestibular hypofunction on reading acuity scores, and (3) the relationship between these scores and a test of dynamic visual acuity.

RESULTS

The test was reliable (ICC (3,2)>or=0.86). Reading acuity scores were significantly worse in children with vestibular hypofunction (p<or=0.002). Furthermore, reading acuity scores correlated with dynamic not static visual acuity scores (r=0.55, p<0.001).

CONCLUSIONS

These results imply that the gaze instability due to vestibular hypofunction affects reading ability in young children.

Central somatosensory changes and altered muscle synergies in subjects with anterior cruciate ligament deficiency

To clarify the mechanisms of compensation in subjects with anterior cruciate ligament deficiency (ACL-D), we examined proprioception, quadriceps strength, somatosensory evoked potentials (SEPs) and muscle responses during gait in varied combinations of speed and incline. Seventeen subjects with ACL-D were grouped by functional level and report of giving way. Seven subjects without ACL-D served as a control sample for muscle response measures. ACL-D subjects with quadriceps weakness experienced giving way and could not resume sport activities. Those without weakness fell into one of two groups: (1) copers, who had full return to previous activity and no giving way despite proprioceptive loss and altered SEPs, and (2) adapters, who were unable to return to previous activity level and experienced giving way despite neither proprioceptive loss or altered SEPs. The unique muscle pattern in copers during inclined fast walking included larger and earlier hamstring activation. These results suggest that in individuals with ACL-D without a strength deficit, altered SEPs and altered neuromuscular patterns are the factors that enable resumption of pre-injury functional levels. Loss of proprioception may drive the central changes, which in turn drives the development of altered muscle patterns.

Improvement of motor development and postural control following intervention in children with sensorineural hearing loss and vestibular impairment

OBJECTIVE

The purpose of this study was to determine the effect of exercise intervention on the progressive motor development delay and postural control impairments in children with sensorineural hearing loss and concurrent vestibular impairment.

METHODS

Twenty-one children with sensorineural hearing loss and vestibular impairment were randomly assigned to two groups (exercise and placebo) matched for age and gross motor development level. Exercise intervention consisted of compensatory training, emphasizing enhancement of visual and somatosensory function, and balance training. Placebo intervention focused on language development activities. Each intervention was administered three times weekly for 12 weeks. Motor development and posturography testing was completed pre- and post-intervention. To examine the mechanisms of change, somatosensory, visual and vestibular functional effectiveness ratios were calculated from posturography stability scores. Children in the placebo group later participated in exercise intervention, and a second post-test completed. Data were analyzed by group, as well as merged once all had received exercise intervention.

RESULTS

Post-intervention, motor development scores significantly improved in the exercise, not the placebo group (P=0.004). Although not significant, improvement in posturography scores were evident in the exercise group. Once the post-exercise data from both groups were merged (n=21), improvements in these scores were significant (< or =0.02). The difference from the normative sample was eliminated.

CONCLUSIONS

Exercise intervention focused on the enhancement of sensory integrative postural control abilities is effective for the arrest of the progressive motor development delay in children with sensorineural hearing loss and vestibular impairment.

A clinical test of dynamic visual acuity for children

OBJECTIVE

Children with sensorineural hearing impairment (SNHI) and concomitant vestibular hypofunction demonstrate deficits in gaze stability that may affect reading. The objective of this study was to develop a reliable, valid clinical test of dynamic visual acuity (DVA) for children.

METHODS

Seventy-six typically developing children, 26 adults and 11 children with sensorineural hearing impairment participated. Visual acuity was tested under three conditions: (1) head stable (static acuity), (2) head tipped forward 30 degrees and passively rotated 30 degrees in the yaw plane at 2 Hz (horizontal dynamic acuity) and (3) head passively moved in the pitch plane 30 degrees at 2 Hz (vertical dynamic acuity, vDVA). The difference, in number of chart lines, between static dynamic acuity was calculated (dynamic acuity score). Based on normative data collected, results were scored as: (1) pass < or =2S.D. from the normative mean and (2) fail > or =2S.D. from normative mean. Children were grouped by age to enable examination of the effect of age on scores.

RESULTS

We found excellent test-retest and inter-tester reliability (ICC(2,2)=0.94 and ICC(3,2)=0.84) for the horizontal dynamic acuity (hDVA) test. Sensitivity, specificity, positive and negative predictive values were 100% to identify children with bilateral vestibular hypofunction (BVH). Although a statistical difference was found, the difference was not clinically significant (all achieved DVA scores <2 lines). The vertical dynamic acuity test was not tolerated by most children, precluding its usefulness.

CONCLUSIONS

The clinical test of horizontal dynamic acuity is a reliable test for children as young as 3 years. It is simple and inexpensive, and will enable identification of those for whom more extensive testing is warranted.

Evidence of progressive delay of motor development in children with sensorineural hearing loss and concurrent vestibular dysfunction

Gross motor development, and the effect of age, sex and vestibular function on it, was examined in 39 24- to 83-mo.-old children with sensorineural hearing impairment. Repeated testing was completed on 18 children. Delayed gross motor development was evident regardless of age, but only children less than 5 years of age had developmental balance deficits on initial testing. Both gross motor and balance development scores were lower on repeated testing. Furthermore, vestibular function scores facilitated identification of those children with a deficit in balance development as well as those with a progressive delay in motor or balance development. Implications for practice are discussed.

Visual-Vestibular Habituation and Balance Training for Motion Sickness

Background and Purpose. This case report describes physical therapy for motion sickness in a 34-year-old woman. The purpose of the report is twofold: (1) to provide an overview of the literature regarding motion sickness syndrome, causal factors, and rationale for treatment and (2) to describe the evaluation and treatment of a patient with motion sickness. Case Description and Outcomes. The patient initially had moderate to severe visually induced motion sickness, which affected her functional abilities and prevented her from working. Following 10 weeks of a primarily home-based program of visual-vestibular habituation and balance training, her symptoms were alleviated and she could resume all work-related activities. Discussion. Although motion sickness affects nearly one third of all people who travel by land, sea, or air, little documentation exists regarding prevention or management.

Extraretinal eye position signals determine perceived target location when they conflict with visual cues

To examine the role of extraretinal eye position information (EEPI) in visual perception of target location in normal room illumination, subjects participated in experiments in which EEPI was manipulated using the eye press maneuver with either monocular or binocular viewing. The viewing condition and eye press caused EEPI and retinal information about target location to conflict. Pointing responses in eye press trials were all in the direction of EEPI showing that EEPI is the dominant source of information in egocentric visual space perception. In binocular viewing, version and vergence occur in response to the eye press to maintain fusion and EEPI based on these movements also determine perceived location. An unanticipated finding was that the eye press was variable in its effectiveness in rotating the eye, which contributed to large variability in pointing errors and suggested the method would be a poor choice for future work.

Head and trunk movement responses in healthy children to induced versus self-induced lateral tilt

The purpose of our study was to determine head and trunk movement responses that occur in healthy 7-year-old children during induced and self-induced lateral tilt. Twenty subjects, while tailor sitting on a tiltboard, participated in three trials of both induced and self-induced left and right lateral displacements. Measurements of neck and trunk lateral flexion; trunk counterrotation; and neck, trunk, and body anterior-posterior movement were obtained from slide transparencies made at three stages of tilt (original position, initial tilt, and full tilt). For each subject in the two test conditions, changes in these measurements between the stages of tilt were determined and compared. Based on the results of multivariate analysis of variance procedures, we concluded that 1) a significant difference in trunk counterrotation existed between the two types of tilt, with the greatest degree of counterrotation occurring with induced displacement; 2) no significant difference existed in neck or trunk lateral flexion; and 3) no significant differences existed in neck, trunk, or body anterior-posterior movement between tilts. We also found that a wide variability of response existed among the children over the three testing trials. Clinical application of our results suggests that different and unique motor programs exist for automatic and willed balance responses. These differences should be considered when planning treatment strategies.