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Head Control Changes After Headpod Use in Children With Poor Head Control: A Feasibility Study

Brown, Julie E. PT, DPT, PhD, PCS; Thompson, Mary PT, PhD, GCS; Brizzolara, Kelli PT, PhD, OCS

Author Information
doi: 10.1097/PEP.0000000000000492
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INTRODUCTION AND PURPOSE

Cerebral palsy (CP) is the most common physical disability affecting children and results in problems with motor control, posture, coordination, and movement.1 These deficiencies limit participation, which is linked to diminished quality of life.2 Children with CP often struggle to have adequate postural control to engage in their environment. Habilitation approaches are aimed to enhance postural control so as to maximize the child's participation in the environment. While not all children with CP have poor head control, children who are classified as Gross Motor Function Classification System (GMFCS) level V, the most severely involved children, have difficulty maintaining their head and the cervical spine in an upright position. There are limited treatment options available to assist a child with poor head control.

Head control is a prerequisite skill children needed to maximize engagement in the environment and provides a solid foundation for integrating vision, oral-motor skills, trunk and arm control, and safe eating.3,4 Furthermore, vital tasks such as respiratory function can be compromised if good head and spine alignment are not achieved.5 Therefore, it is important for therapists to address poor head control. However, it is rarely addressed in severely involved children after infancy.

The typical compensatory approach to poor head control in children is the use of adaptive equipment. Examples of adaptive equipment include custom seating systems, such as a wheelchair with head support necessary to maintain optimal posture. Introduced in the United States in 2013, the Headpod (Siesta Systems, Arre, Spain) reportedly facilitates head control and enhances the child's ability to participate in the environment. The Headpod is a dynamic head support system that (1) provides assistance to maintain neutral head position, (2) restricts flexion, extension, and lateral flexion, but (3) allows full active head rotation. This device includes a suspension arm, an adjustable arc, a frontal strap, an occipital mesh, a scaled rubber strap, and various adaptors. The adjustable arc is sized for the child, and the occipital mesh and frontal strap are attached to the arc and the component donned on the child's head. The scaled rubber strap is attached to the top of the arc. With the scaled rubber strap, the arc is hung to the suspension arm, which is mounted to the adaptive device via an adaptor (Figure 1). With the variously configured adaptors, the device can mount onto almost any wheelchair, seating system, standing frame, or gait trainer. There are optional chin and anti-slip straps to accommodate children with poor head control and who may push or pull. There is only anecdotal evidence to support use of this device. Therefore, the purposes of this study were to determine whether (1) Headpod use is feasible as a home-based intervention to improve head control for children with CP (GMFCS Level V) or with other similar neurologic disorders, and (2) parents of children with poor head control perceive changes attributed to the Headpod.

Fig. 1.
Fig. 1.:
Headpod frontal schematic. Reprinted with permission from Siesta Systems S.L.

METHODS

Participants

An a priori power analysis was conducted to determine minimum sample size required to find significance with a desired level of power set at 0.80, an α level at 0.05, and a large effect size of 0.60(f) using G*Power, version 3.1.7 (Heinrich-Heine University, Dusseldorf, Germany). Since there was no literature to determine sample size, we used data from the first few participants for the a priori power analysis. Based on the G*Power output, it was determined that a minimum sample size of 7 children was required to ensure adequate power for the repeated-measures analysis of variance (ANOVA). Fourteen children (3-11 years) were enrolled because of anticipated high attrition rate due to the medically fragile nature of children with GMFCS Level V and corresponding family stress.

Children 2 to 14 years old with poor head control and a neurologic diagnosis were eligible for inclusion in the study. Poor head control was defined as the inability to hold the head upright against gravity for more than 5-minute increments and requiring adaptive seating to adequately support posture. Children were excluded from participation if they could not tolerate wearing the Headpod defined as uncontrolled crying in the device or skin irritation for greater than 20 minutes after device use or were not medically stable. All children in the study were screened over the phone by the investigator before being evaluated for the study. All children assessed were recruited for the study. Children withdrawn from the study were those who could not continue to tolerate wearing the device, had a significant change of status for more than 3 weeks, such as hospitalization, surgery, or were nonadherent with the device-wearing schedule. Participants were recruited primarily by word of mouth from treating therapists and durable medical equipment providers. Texas Woman's University Institutional Review Board approved the study.

Study Design and Outcome Measures

This study was a quasiexperimental design without comparison group with data collected at 3 time points: baseline and after 3 and 6 months of Headpod use. Head control was quantified by 2 primary outcomes and assessed via 2-dimensional video analysis. Active time was calculated by adding the time in seconds in which the child kept visual engagement on task by holding his or her head upright against gravity to participate in a motivating activity during a 5-minute video capture. Active time served as a proxy of the child's integration of cognitive, visual, and motor systems to participate in a task. Head bobs were counted using the same video captures. Head bobs were defined as uncontrolled sudden hyperflexion or hyperextension of the head and inability to maintain visual task engagement. The number of head bobs is an impairment measure and served as a proxy for the lack of adequate head control. While not specific to children with poor head control, video analysis has good test-retest6 and good intra- and intertester reliability with the use of standardized techniques.7

Secondary outcomes included (1) adherence as determined by daily recording of device use on a monthly log sheet and (2) perceived improvement via a 3-question, 15-point global rating of change (GROC) scale survey with an open-ended comment section. The GROC survey was completed at the 6-month assessment by the last 5 children to complete the study. With scores ranging from −7 to 0 (neutral) to +7, parents were asked to rate the (1) amount of their children's head control change (worse to better); (2) likelihood that the Headpod will continue to be used (never to always); and (3) number of important/useful changes seen (none to many). Researchers have used GROC scales to quantify orthopedic treatment efficacy, with the instrument shown to be quick, reliable, and easy to administer.8 However, the GROC has limitations in clinical orthopedic populations.9 It is possible that GROC scores can be biased toward discharge status, especially when the time elapsed since initiation of treatment is 6 months as in this study.

Procedures

If the investigator deemed the referred child appropriate (inclusion criteria met), she described the study to the parent by telephone who then gave verbal consent. The referring therapist/durable medical equipment provider coordinated the 30-minute visit during which the investigator screened the child for Headpod tolerance prior to enrollment. During this education and fitting session, the investigator adjusted the Headpod to the child's head dimensions and checked for fit. The child then wore the device for 5 minutes to ensure tolerance and appropriate head positioning. The angle of child's body was adjusted until some active movements were possible in the neck with activity engagement. Following successful 5-minute use of the device, the investigator worked with parents and again demonstrated correct Headpod donning/doffing procedures and body positioning while using the device. The parent/caregiver practiced donning the device and could ask questions to ensure understanding. In addition, written handouts were given to the parents to help guide donning process. The investigator explained the minimum daily use requirements and mounted the Headpod where the parent indicated. If the child had a successful Headpod fitting and the parent and the child were in agreement to participate, the consent form was signed and parents received logs to record device use. The informed consent included the investigator's telephone number in case the parent had questions or concerns. The Headpod trial was judged successful if the device stayed securely positioned on the child's head, supporting the head in an upright position against gravity for 5 minutes while the child was actively engaged in tasks without incurring skin redness or the child crying uncontrollably.

The investigator videotaped baseline head control without the Headpod and ensuring that the child was secured in his or her usual adaptive equipment in good alignment. Two grid boards were placed 2 ft behind the participant's head in both the frontal and sagittal planes to enhance later video analysis. Two video cameras on tripods, each placed 2 ft from the participant, were adjusted to nose level frontally, and at ear level sagittally. The child was videotaped in frontal and sagittal views while the child was encouraged to participate in a meaningful activity for 5 minutes.

Over the next 6 months, the parent was asked to apply the Headpod at least 3 times per day for 15 minutes each time (total of 45 minutes per day) while the child participated in an activity that was motivating to the child to ensure maximal participation. The reason for recommending these short periods of Headpod use was to avoid overfatigue of the neck muscles and to minimize disruption of family routines. The Headpod could be used during eating or any other regular daily activity that lasted about 15 minutes. The parent daily recorded Headpod use on 3 monthly log sheets and placed the log in a sealed envelope that was collected at the 3- and 6-month assessments. At each assessment session, the video recording was repeated using the same procedures and equipment setup as described at baseline. At the final 6-month assessment, parents also completed the GROC survey.

Postintervention Video Analysis

To minimize investigator bias, the investigator did not view or analyze the video captures until all data collection was complete. The investigator systematically documented the primary outcomes by viewing the slowed videos. Using the embedded video time stamps, each second of active engagement observed in each video capture was highlighted on the video analysis form time grid (300 blocks available on the time grid, 1 block per second, 300 seconds per 5-minute period) and active times were summed. Similarly, head bobs were counted. Frontal and sagittal views were analyzed separately and then averaged for statistical analysis. This postintervention analysis of video captures was repeated independently by a pediatric occupational therapist to determine interrater reliability.

Data Analysis

Data were analyzed with SPSS for Windows, version 24 (SPSS Inc, Chicago, Illinois). To test the assumption that the video analysis data (active time and head bobs) were reliable, 2 interrater reliability analyses were performed on the data collected from each rater using a 2-way random-effects model (ICC2,1). To determine whether head control improved over time, a 1-way repeated-measure Friedman ANOVA test was run on each variable (active time and head bobs). Prior to this analysis, weighted adjustments for time equivalency were made on the first 4 participants when the sagittal video data were 2 minutes rather than 5 minutes. Then, the sagittal and frontal view counts were averaged to derive the active time and head bobs data used in the 2 Friedman ANOVAs. A significant Friedman test was followed with a Wilcoxon signed ranks test to find out between what time points the differences occurred. A post hoc effect size was calculated to determine the magnitude of the improvement using an effect size calculator, G*Power, and an observed power for the P value was computed. Descriptive statistics from GROC survey were calculated, and common themes of the open-ended question were summarized to investigate whether parents perceived changes in their children's head control attributed to Headpod use over the 6-month period. Study adherence is total minutes of Headpod use as prescribed over the 6-month period.

RESULTS

A total of 14 children (mean age 7 years) with poor head control were enrolled in the Headpod study (Table 1). All participants had neurologic diagnoses as their primary impairment, but presented with multiple impairments. Each participant had global delays. All participants were severely physically involved and were classified as GMFCS level V. Twelve children had CP. One child had FOXG1 syndrome, a rare neurodevelopmental disorder caused by a gene mutation that is usually diagnosed as ataxic CP prior to genetic testing.10 Another child had Lennox-Gastaut syndrome, a severe form of epilepsy, commonly caused by perinatal hypoxia, stroke, or traumatic brain injury.11 Most patients with Lennox-Gastaut syndrome also have CP and severe intellectual disability.

TABLE 1 - Participant Characteristics and Headpod Compliance
Participant # Sex Age, y Diagnosis Study Completion Reported Total Minutesa Used (%)
1 Male 11 Cerebral palsy Complete 1515 (20.0)
2 Male 9 Cerebral palsy Complete 835 (11.0)
3 Female 3 Cerebral palsy Complete 5325 (70.4)
4 Female 8 Cerebral palsy Headpod intolerance
5 Male 9 Cerebral palsy Lost to follow-up
6 Female 7 Cerebral palsy Complete 2053 (27.2)
7 Female 5 Cerebral palsy Deceased
8 Male 10 Cerebral palsy Complete 8616 (114.0)
9 Male 3 FOXG1 syndrome Complete 6540 (86.5)
10 Male 5 Cerebral palsy Complete 2210 (29.2)
11 Female 10 Lennox-Gastaut syndrome Completeb 1873 (24.8)
12 Female 3 Cerebral palsy Complete 7000 (92.6)
13 Female 3 Cerebral palsy Headpod intolerance
14 Female 11 Cerebral palsy Lost to follow-up
aTotal prescribed Headpod time engaged in an activity = (15 minutes)(3 times/day)(28 days/month)(6 months) = 7560 minutes.
bVideo data not analyzed secondary to no Headpod use as prescribed after month 4.

Five of the 14 children dropped out of the study between baseline and 3-month assessments. Of these 5 children, 1 unexpectedly died from acute illness, leading to multiple body system failure; 2 participants, despite the initial tolerance, could not wear the device per the prescribed regimen without crying; and 2 others were lost to follow-up because parents could not be reached to schedule the 3-month assessment. One additional participant (#11) did complete all testing, but did not wear the Headpod as prescribed after 4 months due the mother's report of “busyness.” Therefore, her child's video data were not included in the primary outcome analyses. Based on the 8 participants with video analysis data, the attrition rate was 43% at 6 months. Adherence as reported on the logs appears in Table 1 by the 9 participants who completed the study. On average, parents logged 3996.3 minutes of Headpod use with the child activity engaged in a meaningful activity, or 52.9% of the prescribed 6-month dose (7560 minutes).

Interrater reliability of the primary outcome measures was excellent12 for active time with an ICC2,1 = 0.943, and good for head bobs with an ICC2,1 = 0.761. Sample head control at baseline and at 3 and 6 months of Headpod use had improvements at each follow-up time point (Table 2). Note that for head bobs, at all points in time, the standard deviation exceeded the corresponding mean. The Friedman ANOVA revealed differences in active time over the 3 assessment sessions, but not head bobs. The Wilcoxon signed ranks test indicated that active time at 6 months was significantly higher than at baseline (Z = −2.521, P = .006) and at 3 months (Z = −2.028, P = .022). The 3-month to baseline comparison was not statistically significant (Z = −5.60, P = .288). Therefore, it takes more than 3 months of 45 minutes per day Headpod use in engaging activities before change occurs. The Spearman rank correlation coefficient calculated between average active time change from baseline to 6 months and average head bob change from baseline to 6 months was moderately related and marginally significant (rs = −0.746, P = .054). As average active time increased, average head bobs decreased. There were moderate to strong nonsignificant relationships between change in outcome measures and reported total minutes of Headpod use. Children who spent more time in the Headpod tended to benefit from it in terms of change in active time (rs = −0.6, P = .120). The strength of the relationship was less (moderate rs = 0.3, P = .500) in terms of change in head bobs. The correlation coefficients inform us of the magnitude of the association between variables and are independent of sample size, whereas P values are affected by sample size and reflect the degree of confidence in the magnitude of the association. Figure 2 illustrates head control performance as measured by active time by participant.

Fig. 2.
Fig. 2.:
Head control expressed as active time during 3 assessment sessions: at baseline and after 3 and 6 months of Headpod use. No 3-month data for participant #1 secondary to video failure.
TABLE 2 - Head Control Performance by Assessment Time
Variablea Mean (SD) Median Minimum Maximumb P Value Observed Power
Active time, s .018c 0.926
Baseline 190.33 (42.31) 166.00 150 274
3 mo 204.63 (58.46) 209.50 122 288
6 mo 278.00 (24.97) 286.50 227 300
Change baseline to 6 mo 83.63 (38.07) 79.50 17 134
Head bobs, n .664 0.165
Baseline 3.13 (3.44) 3.00 0 10
3 mo 2.75 (3.11) 1.50 0 8
6 mo 1.88 (3.10) 0.50 0 9
Change baseline to 6 mo −1.43 (2.22) −1.00 −4 1
aMissing data on 1 participant at 3 months, n = 7; at baseline and 6 months, n = 8.
bMaximum possible = 300 s.
cDifferences are between baseline and 6 months (P = .006) and between 3- and 6-month assessments (P = .022).

The magnitude of the active time improvements is considered large.13,14 The 3-month active time compared with the 6-month active time had an effect size of Cohen's d = 1.476. The baseline active time compared with the 6-month active time had an effect size of Cohen's d = 2.570. Therefore, the Headpod had a large effect on increasing the active time children were able to hold their head upright to engage in an activity. This finding was supported by the GROC results from the parents of the last 5 participants to complete the study. This small subset of parents perceived their children's head control was better (median = +5, range from +2 to +7); would likely continue to use the Headpod (median = +6, range from +5 to +7); and noticed a number of important/useful changes (median = +5, range from +5 to +7). In the open-ended comment section, parents most frequently (n = 3) said that the Headpod helped with feeding and visual tracking and that the changes were apparent.

DISCUSSION

This study provides evidence that children with little to no head control who tolerate the Headpod and whose parents persist with its daily use for 6 months may show improvements in the length of time for which they are able to hold their heads upright independently.

There are several limitations in this study. Consideration of these limitations may help guide future research on the Headpod as well as guide its use in clinical practice. The home-based Headpod intervention program was designed to minimize caregiver stress by keeping the program simple and easily integrated into typical everyday activities. It is well documented that parents of children with CP experience caregiver stress in multiple domains.15 Lowes and associates' findings help explain in part the high attrition rate and adherence issues in the Headpod study. All 14 children had severe impairments that interfered with their activities and participation. Since the child is dependent on parents for all activities of daily living and participation in the study, both the parent and the child must be motivated to participate. The parent must be motivated to allow the child to participate in the study per the prescribed regimen, and the participant must be motivated to be engaged in an activity. Parents often have full schedules just performing activities of daily living for the participant. Time constraints may account for using the Headpod less often than prescribed. It is understandable why parents of children with multiple disabilities would not complete the entire 15-minute session or would discontinue the use of the device if the child cried despite an earlier successful Headpod trial. The 30-minute Headpod education and fitting session may not have been long enough to address potential parental concerns about why the child might be crying. It is possible that participants #3, 10, and 12, whose 3-month active time was similar or worse compared with their baseline performance, may have benefited from working more closely with a therapist to work through fitting challenges.

Despite the high 43% attrition rate and only 53% adherence with the prescribed dose, it appears that for children aged 3 to 11 years with CP (GMFCS level V) or with similar nonprogressive conditions the Headpod can be used as a daily home-based intervention to improve head control in terms of active time in which children are able to hold their head upright to participate in an activity over a 6-month period.

The limitations of the study should be considered when interpreting these conclusions, including device tolerance and adherence. Overall, 3 participants' discontinuation use of the Headpod was related to the treatment (2 were unable to tolerate using the device for the treatment time while 1 was too busy), 1 participant's discontinuation was unrelated to the Headpod itself (death), and 2 participants' discontinuation reasons are unknown as they were lost at follow-up. For the group of children withdrawn from the study secondary to intolerance of using the device postenrollment, additional training (verbal, written, and hands-on) for the parent/caregiver to gain more confidence on donning the device might have helped improve the participant's tolerance. Follow-up sessions along with reassurance that the device is not harming the child may be helpful for future studies. If the child tolerates the device, and both the child and the parent are motivated to actively work on head control, improvements are readily apparent, with the child better able to visually track people and objects in the environment. The large magnitude of change is counter to conventional thinking. Based on GMFCS level V reference curve predictions, minimal gross motor improvement occurs between children aged 3 and 6 years, and after age 6 years, gross motor decline is seen.16 Therefore, clinicians typically do not address head control beyond passive support of the head, and researchers typically focus their efforts on interventions for less-involved children where there is a belief that improvements can still occur. Dewar, Love, and Johnston17 published a systematic review in 2015, on exercise interventions that may improve postural control in children with CP. Of the 45 articles published between 1980 and 2013, only 2 included children with a GMFCS level V. Evidence from the Headpod study suggests not only that change in head control expressed in active time may occur, but it may be possible for some children to achieve substantial improvements. While most of the participants had been receiving ongoing habilitation since birth and school-based therapies, parents were not asked about the amount and type of therapy. Parents were told to continue their normal routine and to report changes in health status. While the seating system each child used during the study period did not change, it is possible that other factors outside of Headpod use could have contributed to the observed changes.

Nevertheless, some participants' active time changed more than others. While all participants were homogeneous with respect to their level of disability, the target population is medically fragile with severe involvement and multiple disabilities. Each participant differed in muscle tone, resting posture, and compensatory strategies used to overcome weaknesses. Individual differences in small samples may confound results and may explain why some improved more than others. Participant #9 had the highest baseline active time and improved the least (6%), possibly owning to a ceiling effect (5-minute video clip may be too short). The other participants experienced improvements of 28% to 88% from baseline to 6 months, with 2 participants (#2 and #8) able to control their head for the entire 5 minutes. Participants with a lower baseline active time improved more than those with higher active time at baseline. When comparing the mean change in active time from baseline to 6 months, participants held their head upright 1 minute 39 seconds more per 5-minute increment. This translates to a 30% increase in active time from baseline to 6 months. In addition, when comparing the mean change in head bobs from baseline to 6 months, participants demonstrated 1.2 less head bobs in a 5-minute increment from baseline to 6 months. This correlates to a 39% reduction in head bobs. The ability to engage in the environment greater than 30% more each day is a significant improvement, which could have life-changing consequences. All participants were required to tolerate wearing the device during the initial screening, prior to being enrolled in the study.

The findings of the Headpod study should be interpreted in light of its limitations that include the small sample size, lack of a control group, nonblinded video time points to raters, and equipment issues. The primary limitation is the small sample size because of difficulty in participant recruitment and retention, and a relatively small target population. Small samples may not reflect the population mean, and generalizability may be limited. In addition, there was not a control group. This feasibility study would have been stronger if we had anticipated the very small sample size and planned for an A-B single-subject design with multiple data points in each phase to compensate for lack of a control group.12 In addition, the independent video raters were not blinded to video time points for video analysis. And, raters were aware of the hypothesis of the study—that active time holding head upright to participate in an activity would increase by daily use of the Headpod over a 6-month period. These limitations prevent us from confidently attributing the observed changes to the Headpod alone.

Equipment issues included video failure leading to missing data, as mentioned earlier and Headpod issues. Since the investigator travelled to participants' homes for all measurement sessions, traveling with a spare set of video equipment would be wise for future studies. Regarding the Headpod, initially there was no grant funding, resulting in procurement time delays secondary to the health insurance approval process and caregiver cost sharing. Siesta Systems provided a grant in the form of demonstration Headpods for the last 6 participants (#9-14). There were a few essential strap durability concerns with the Headpod. This was especially seen on the participants who were “pullers.” A broken strap for participant #10 caused a few days of nonadherence that could not be controlled and may have affected study results. Since then, the manufacturer has made straps out of a more durable material.

CONCLUSIONS

This is the first study to examine use of the Headpod to change head control in children aged 3 to 11 years with severe and profound impairments and restricted activities and participation. Despite study limitations, 6 months of Headpod use, 45 minutes per day in 15-minute intervals, appears to have a large effect on active head control for children who can tolerate it and thus may merit a larger randomized controlled trial.

In addition to a randomized control trial of the Headpod as an intervention and measuring head control with the device removed, other studies should be carried out to examine the efficacy of the Headpod as an adaptive device to enhance participation. According to the manufacturer, the Headpod can be used as an adaptive device to assist the child in participating in activities such as eating, visual gazing, listening, and enhancing overall participation.

More studies beyond use of the Headpod are needed. Head control can change in children with severe neurologic involvement, but we need to determine the best way to measure head control and detect change over time. We added the GROC to capture and quantify parental perceptions and opinions for the last 5 participants because several parents of early participants expressed noted improvement of their children. However, the GROC as a measure of perceived change has not been used in studies involving children and their families beyond theses and dissertations. The GROC was developed as a patient-reported outcome measure for persons with orthopedic conditions, and it is unclear whether the measurement properties and limitations are generalizable to children and their parents. It is unknown whether perceived change is equal to “true” change9 in our target population. Nevertheless, the valuing perceptions of children and their families is one of the hallmarks of family-centered care.18 Incorporation of more automated techniques to log daily use of the device may help improve compliance. Ultimately, improvements in activity influence quality of life.

ACKNOWLEDGMENT

I would like to acknowledge my dear friend Joan Cain, OTR, for all her time spent independently viewing videos to assist in the interrater reliability component of this study.

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Keywords:

adaptive seating; cerebral palsy; motor development; motor function; seated position

© 2018 Academy of Pediatric Physical Therapy of the American Physical Therapy Association