The objective for this section is to review key issues to consider in conducting studies of TBI outcomes in children and youth.

Meeting participants had a wide range of experiences in obtaining information from children with TBI, their families and schools. These sections document participants’ ideas about the challenges of designing and implementing a study of outcomes of TBI in children and youth and how they should be managed.

Considerations for Defining the Study Population

Meeting participants discussed how representative the study population would be if children were selected for follow-up using the same approach used in CDC follow-up studies of older adolescents and adults. That approach, which identifies cases from surveillance systems using hospital discharge data sets, has some important limitations:

• It may underestimate problem outcomes because those who can still be identified and followed after one-year post-hospital discharge tend to have more resources and more stable lives (for adults followed in the Colorado follow-up system, about 35% are lost to follow-up within one year).
• It probably does not include an adequate subsample of children from low-income families.
• It does not include children seen in the emergency department (ED) but not admitted to hospital. The majority of children with TBI are seen only in the ED.

Sampling Frame

Participants discussed an appropriate sampling frame for selecting cases for follow-up studies of children. They determined that the sampling frame should include both children treated and released from the ED and children discharged from the hospital. The population should then be stratified by severity before selecting the sample.

Participants also discussed whether the study should collect information from parents / caregivers or schools:

• A study should include assessments of both the parent (caregiver) and older children (age 8 to 10 or older). Parents and children may differ in reporting, especially about the social experiences of the child, with the parent reporting that the child has more friends and fewer problems with peer interactions than the child reports.

• A study should incorporate school assessments of the child’s abilities, if possible.

• Parents’ and teachers’ understanding of the child’s individual educational plan (IEP) may differ, so getting both perspectives is important.
• Parents tend to rate their child's school performance higher than do school personnel. The more time that has elapsed since the injury, the higher parents tend to rate pre-injury performance (including school performance).
• Interviews of teachers could yield some valuable information, especially for younger children who have one teacher only.
• Information from school records may also be useful; however, school records may not be complete, and schools are inconsistent in classifying children’s disability. For example, a child with a brain injury may be classified as having a learning disability, not a TBI. School records may not be a thorough source of information about grade retention and services received, but these areas are important, so a study should obtain information about them using other methods if necessary.
• Other school-related information of interest includes drop-out rates, achievement on statewide standardized tests and transfers to alternative schools.
• Whether obtaining information requires IRB approval from each school might vary by location, so researchers should check before beginning the study.

Appropriateness of Telephone Interviews for Children / Youth Follow-up Studies

Instead of using in-person interviewing, which is very expensive, CDC has used telephone interviewing to collect information in its follow-up studies of older adolescents and adults. Meeting participants discussed the appropriateness of this approach for studies among children and youth.

Before beginning telephone interviewing, researchers should investigate telephone coverage among the proposed study population because low-income families may not have telephones. Researchers might also consider newer alternatives such as Internet administration, but Internet coverage among low-income families is likely to be even lower than for telephones.

Studies show that responses vary according to mode of administration (telephone vs. in-person and, for in-person interviews, whether the interview is conducted by a doctor/nurse or other type of interviewer). People tend to report fewer impairments when they are interviewed in-person than when they are interviewed by telephone. Therefore, researchers might need to compare responses from in-person and phone interviews in a sample of participants to evaluate reliability.

Interviewing Children by Telephone

Studies suggest that interviewing by telephone may not be appropriate for children and youth younger than age 13. TBI-related deficits and problems such as fatigue and limited attention span may make phone interviews with young people more difficult.

• Pilot the questionnaire and revise based on results and experience before beginning the main study.
• Consider mailing the parent questionnaire before the interview to give them time to think about their answers.

Appropriate Interview Length

• Questionnaires for use with children and youth with TBI should be as short as possible to minimize fatigue among participants. Questionnaires for use with their parents may be longer but should also be kept as short as possible.
• Interviews should not exceed 45 minutes for adolescents while approximately 60 minutes is appropriate for parents. Meeting participants suggested that questionnaires for use with children should be pilot tested to determine the appropriate interview length.
• Meeting participants also suggested pilot testing a longer version for use with adolescents or parents to see how they respond. Families of children with TBI may be very invested in outcomes and often like to have someone to talk with. Some meeting participants reported surprise at the willingness of parents to be interviewed for longer than 60 minutes.

Effective Follow-up Interviews

Longitudinal studies of TBI outcomes involve an initial interview sometime after TBI, then tracking participants and re-interviewing them periodically, often at one-year intervals. Of particular concern is the potential for loss to follow-up because the families move or no longer agree to be part of the study. Meeting participants offered these suggestions for follow-up with children who have TBI:

• Begin interviewing earlier than one year after the injury (optimally at 3-6 months). This approach could help decrease loss to follow-up because the family is less likely to have moved from the address found in the medical record. This approach would also provide useful information about patterns of early recovery.
• Consider beginning active surveillance and follow-up while people are still in the hospital.

Follow-up beginning at one year is not timely enough to meet the needs of people with TBI to be identified early and linked to information that can help them get the services they need. Meeting these needs requires a case management approach, even if it is cost- and resource-intensive. The principal investigator for the South Carolina follow-up study of older adolescents and adults estimates that double the funding it currently receives from CDC would be required to initiate active surveillance of TBI. To decrease the cost and improve the feasibility of conducting more active surveillance, researchers should consider limiting surveillance to the few hospitals that see the majority of child TBI cases—for example, Level I trauma centers and children’s hospitals.

• Consider alternative approaches to tracking, especially for very young children, such as early intervention tracking systems that follow very young children (younger than age 3) who have TBI or other disability (e.g., in Rhode Island).

A single year of follow-up is insufficient to document important outcomes. Ideally, a study should follow children as long as possible through as many developmental transitions as possible to try identifying late-emerging problems resulting from TBI. Based on experience with the currently funded CDC studies of outcomes in older adolescents and adults, three- to five-year follow-up is feasible considering estimated cost and loss to follow-up.

To reduce loss to follow-up, researchers should test a mechanism for routinely contacting participant families, such as sending a postcard at frequent intervals to track changes of address.

Advantages of and Selected Methods for Comparison Groups

Meeting participants strongly recommended including a comparison group as part of any follow-up study of outcomes of TBI in children to strengthen the study design and improve the usefulness of the findings. A comparison group completes the same questionnaire as the follow-up study participants, and researchers compare their responses with those of the children with TBI. The comparison group need not be the same size as the group of children with TBI. Methods of selecting a comparison group vary. Meeting participants discussed the pros and cons of each method, as summarized below:

This approach entails selecting a population of children who were injured but did not have a TBI, matched by age and sex with the TBI children. The approach helps control for risk factors for injury that are similar between the two groups. The comparison group should be matched by socio-economic status to the TBI group.

• Researchers should consider the length of time following the trauma in selecting the comparison group. If the concern is adjusting for pre-injury risk factors only, selecting children who have recovered from the trauma may be more appropriate.
• Keeping non-TBI trauma controls involved in the study requires much effort, especially if they will be interviewed more than once, because they are not as invested in it as family members.
• Meeting participants strongly recommended this approach.

This approach involves selecting one similar-aged friend for each child with a TBI. The "friend control" completes the questionnaire. The approach helps control for social environment and school context, but friend controls might not have the same pre-injury risk factors.

• Defining "friend" may be difficult for very young children. Also, many children lose their friends after the TBI, so identifying a friend control may be difficult.
• Keeping friends involved in the study requires effort because they are not as invested in it as family members.
• Meeting participants recommended this approach as useful but with several limitations.

This approach involves selecting a brother or sister of the child with TBI to serve in the comparison group. The approach helps control for family environment factors, but matching on age and sex may be impossible or there may not be any siblings.

• Siblings may not be a good comparison group because, as part of the family of the child with TBI, they also feel effects of the trauma.

• Meeting participants did not recommend this approach.

This approach involves selecting a sample of children from the general population, matched by age and sex. The approach allows comparison of the normal developmental trajectory with the trajectory for children with TBI.

• Meeting participants recommended this approach. They also suggested that the optimal study would include both an age- and sex-matched comparison group and a non-TBI trauma comparison group.

This page last modified on September 19, 2006

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