Table of Contents

Locator Record

Title: Balance (BAX_B )
Contact Number: 1-866-441-NCHS
Years of Content: 2001 - 2002
First Published: February, 2005
Revised: NA
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject:Balance
Record Source: NHANES 2001 - 2002
Survey Methodology: NHANES 2001 - 2002 is a stratified multistage probability sample of the civilian non-institutionalized population of the U.S.
Medium: NHANES Web site; SAS transport files

Component Description

Balance disorders constitute a major Public Health concern, especially for older persons, an increasing segment of the U.S. general population. For example, Balance disorders are causally related to the some 200,000 hip fractures that occur annually in Americans over the age of 65. The objectives of the Balance Component are to obtain accurate prevalence data on balance problems among a sample of U.S. adults, to examine the relationship between balance problems and specific covariates such as certain medical conditions and indicators of health status, and to help characterize normal and disordered balance and spatial perception.

The NHANES 2001–2002 Balance Component consisted of two parts:

1. A pre-exam screening questionnaire: This is a series of questions to identify conditions which would constitute either practical or safety exclusions to performing Balance testing. Please note that more extensive survey questions relating to balance problems are contained in the BAQ section of the NHANES household survey questionnaire.

2. Balance Testing: This part consisted of a modified Romberg Test of Standing Balance on Firm and Complaint Support Surfaces (Weber, 1993).

Eligible Sample

The 2001–2001 Balance Component tested a full sample of U.S. adults ages 40+ years. Subjects were excluded from the Balance testing protocol if at the time of the exam, they felt unable to standon their own, were then currently having dizziness sufficient to cause unsteadiness, weighed over 275 lbs., had a waist circumference either too small or too large to accommodate proper fitting of any standard-sized safety gait belt, if they needed a leg brace in order to stand unassisted, or had an amputation of their feet or legs. In addition subjects who were totally blind or visually impaired sufficiently to require assistance in finding the exam room were disqualified.

Protocol and Procedure

The Romberg Test of Standing Balance on Firm and Compliant Support Surfaces examines the ability of the examinee to stand unassisted under four test conditions, ordered in increasing level of difficulty. In TestCondition 1, the subject stands making use of all the sensory inputs that contribute to balance— the central vestibular system, vision, and proprioception (leg muscle position sense). Test Condition 2 tests balance when only vestibular and proprioceptive information is available (the subject closes the eyes to eliminate visual input). In Test Condition 3, the subject must maintain balance on a foam-padded surface, which reduces the proprioceptive input, leaving only visual and vestibular cues. Finally, in Test Condition 4 (also using a foam pad) the eyes are again closed (visual input is removed) and the subject's ability to maintain balance is tested using only the vestibular system.

All Balance Testing was scored on a pass/fail basis, with Test Conditions 1 and 2 conducted for a total of 15 seconds, and Test Conditions 3 & 4 conducted for 30 seconds each. Test failure was defined as 1) a subject needing to open the eyes in an eyes-closed Test Condition (#2 or #4), 2) the subject moved the arms or feet in order to achieve stability, or 3) the subject began to fall or required MEC Technician intervention to maintain balance.

In the standard Balance Testing protocol, each subject is eligible for an initial test and one re-test in order to pass a specific Test Condition. Within each Test Condition, the protocol for retesting is the same as for the primary examination. Because each successive Test Condition from 1 to 4 is progressively more difficult than the Condition preceding it, the Balance Testing Component is ended whenever a subject fails to pass a Test Condition. Balance testing was conducted with the utmost consideration for subject safety. The examining MEC Technician stood immediately to the side of the participant prepared to stabilize the subject by the use of a safety gait belt should significant unsteadiness occur. Also, the examination was conducted in a small exam room, with well padded walls and floor.

The complete NHANES Balance Examination Procedures Manual is located at http://www.cdc.gov/nchs/data/nhanes/ba.pdf.

Quality Assurance & Quality Control

The NHANES Health Technicians were professionally trained in the Modified Romberg Testing protocol by an expert consultant in Balance and Vestibular disorders. In addition, audiologic consultants from the National Institute of Occupational Safety & Health (NIOSH) provided performance monitoring of each Technician on a regular basis. Also, NCHS staff visited the MECs approximately twice per year to observe the Balance examinations and verify Compliance with standard testing procedures. Finally, MEC Health Technicians received annual retraining and updates by the NIOSH consultants. Exclusion rates and outcome statistics for the examination component were continually monitored according to Technician and MEC, and retraining was conducted as necessary to maintain test quality.

Data Processing and Editing

All of the Balance Data were collected using automated data collection methods. A consulting NIOSH Audiologist performed data reviews. In addition, a computerized data review and editing process was utilized to check for logical inconsistencies in the data and technician errors, as well as to cross-check other issues affecting data quality. Back-end edits of the data were performed as necessary when errors were detected.

Analytic Notes

Data analysts should ideally be familiar with Balance and Vestibular disorders, or have a specialist available for consultation. The systematic differences in testing length (15 seconds for Conditions 1 & 2; 30 seconds for Conditions 3 & 4) may also need to be taken into account in the analysis of the data.

Analysts wishing to perform data analysis using combined data from the NHANES 1999–2000 and NHANES 2001–2002 data collection cycles should be aware of the differences in the sampling frame for Balance Examination that took place between the two survey cycles. The NHANES 1999–2000 Balance Component was a ½ sample of U.S. adults ages 40–69 years, whereas NHANES 2001–2002 was a full sample of U.S. adults ages 40+ years. For analysis of the 1999–2000 Balance data alone, the Balance Sub-Sample 2-Year MEC weights provided with that data file should be utilized. For analysis of the 2001–2002 Balance data alone, the regular full sample 2001–2002 MEC Examination weights should be used. For combined 1999–2000 and 2001–2002 data analysis, the special 4-year Balance Sub-Sample MEC weights provided with the 1999–2000 and 2001–2002 data file should be utilized. Please note that these 4-year sub-sample weights are provided only for adults ages 40 to 69 years, which is the age range common to both survey cycles.

References

Codebook and Frequencies

SEQN - Respondent sequence number

Variable Name:
SEQN
SAS Label:
Respondent sequence number
English Text:
Respondent sequence number.
Target:
Both males and females 40 YEARS - 150 YEARS

WTSBA4YR - Balance Subsample 4 Year Mec Weight

Variable Name:
WTSBA4YR
SAS Label:
Balance Subsample 4 Year Mec Weight
English Text:
Balance Subsample 4 Year Mec Weight
Target:
Both males and females 40 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1556.3775566 to 90972.569512 Range of Values 2059 2059
. Missing 1125 3184

BAAEXSTS - Status of a MEC exam

Variable Name:
BAAEXSTS
SAS Label:
Status of a MEC exam
English Text:
Status of a MEC exam
Target:
Both males and females 40 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Complete 2498 2498
2 Partial 85 2583
3 Not done 601 3184
. Missing 0 3184

BAAEXCMT - Comment code for an exam

Variable Name:
BAAEXCMT
SAS Label:
Comment code for an exam
English Text:
Comment code for an exam
Target:
Both males and females 40 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Safety exclusion 302 302
2 SP refusal 96 398
3 No time 11 409
4 Physical limitation 52 461
5 Communication problem 8 469
7 SP ill/emergency 20 489
56 Came late/left early 124 613
99 Other, specify 73 686
. Missing 2498 3184

BAQ110 - Can you stand on your own?

Variable Name:
BAQ110
SAS Label:
Can you stand on your own?
English Text:
Can you stand on your own?
Target:
Both males and females 40 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 2755 2755
2 No 60 2815
. Missing 369 3184

BAQ120 - Do you have a leg brace?

Variable Name:
BAQ120
SAS Label:
Do you have a leg brace?
English Text:
Do you have a leg brace?
Target:
Both males and females 40 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 10 10
2 No 2745 2755
. Missing 429 3184

BAQ130 - Feeling dizzy or lightheaded now?

Variable Name:
BAQ130
SAS Label:
Feeling dizzy or lightheaded now?
English Text:
Are you feeling any dizziness or lightheadedness now?
Target:
Both males and females 40 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 161 161
2 No 2584 2745
. Missing 439 3184

BAXPFC11 - Cond 1 Trial 1 Feet together eyes open

Variable Name:
BAXPFC11
SAS Label:
Cond 1 Trial 1 Feet together eyes open
English Text:
Feet together eyes open:
English Instructions:
Stand in this position with your eyes open, looking at the target for as long as you can or until I ask you to stop. Please do not talk once the test begins. "Begin now."
Target:
Females only 40 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Pass 2552 2552 BAXPFC21
2 Dnp(did not pass) 12 2564
. Missing 620 3184

BAXFTC11 - Cond 1 Trial 1 Failure Time(seconds)

Variable Name:
BAXFTC11
SAS Label:
Cond 1 Trial 1 Failure Time(seconds)
English Text:
Number of Seconds:
Target:
Both males and females 40 YEARS - 150 YEARS
Hard Edits:
0 to 14
Code or Value Value Description Count Cumulative Skip to Item
0 to 14 Range of Values 12 12
. Missing 3172 3184

BAXPFC12 - Cond 1 Trial 2 Feet together eyes open

Variable Name:
BAXPFC12
SAS Label:
Cond 1 Trial 2 Feet together eyes open
English Text:
Feet together eyes open:
Target:
Both males and females 40 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Pass 7 7 BAXPFC21
2 Dnp(did not pass) 5 12
. Missing 3172 3184

BAXFTC12 - Cond 1 Trial 2 Failure Time(seconds)

Variable Name:
BAXFTC12
SAS Label:
Cond 1 Trial 2 Failure Time(seconds)
English Text:
Number of Seconds:
Target:
Both males and females 40 YEARS - 150 YEARS
Hard Edits:
0 to 14
Code or Value Value Description Count Cumulative Skip to Item
0 to 10 Range of Values 5 5
. Missing 3179 3184

BAXPFC21 - Cond 2 Trial 1 Feet together eyes closed

Variable Name:
BAXPFC21
SAS Label:
Cond 2 Trial 1 Feet together eyes closed
English Text:
Feet together eyes closed:
English Instructions:
Stand in this position with your eyes closed, facing the target for as long as you can or until I ask you to stop. First assume this position with your eyes open, and then close your eyes. Please do not talk once the test begins. "Begin now."
Target:
Both males and females 40 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Pass 2403 2403 BAXPFC31
2 Dnp(did not pass) 153 2556
. Missing 628 3184

BAXFTC21 - Cond 2 Trial 1 Failure Time(seconds)

Variable Name:
BAXFTC21
SAS Label:
Cond 2 Trial 1 Failure Time(seconds)
English Text:
Number of Seconds:
Target:
Both males and females 40 YEARS - 150 YEARS
Hard Edits:
0 to 14
Code or Value Value Description Count Cumulative Skip to Item
0 to 14 Range of Values 153 153
. Missing 3031 3184

BAXPFC22 - Cond 2 Trial 2 Feet together eyes closed

Variable Name:
BAXPFC22
SAS Label:
Cond 2 Trial 2 Feet together eyes closed
English Text:
Feet together eyes closed:
Target:
Both males and females 40 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Pass 80 80 BAXPFC31
2 Dnp(did not pass) 71 151
. Missing 3033 3184

BAXFTC22 - Cond 2 Trial 2 Failure Time(seconds)

Variable Name:
BAXFTC22
SAS Label:
Cond 2 Trial 2 Failure Time(seconds)
English Text:
Number of Seconds:
Target:
Both males and females 40 YEARS - 150 YEARS
Hard Edits:
0 to 14
Code or Value Value Description Count Cumulative Skip to Item
0 to 13 Range of Values 71 71
. Missing 3113 3184

BAXPFC31 - Cond 3 Trial 1 Foam Pad Eyes Open

Variable Name:
BAXPFC31
SAS Label:
Cond 3 Trial 1 Foam Pad Eyes Open
English Text:
Feet together eyes open:
English Instructions:
Stand in this position with your eyes open, looking at the target for as long as you can or until I ask you to stop. Please do not talk once the test begins. "Begin now."
Target:
Both males and females 40 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Pass 2410 2410 BAXPFC41
2 Dnp(did not pass) 55 2465
. Missing 719 3184

BAXFTC31 - Cond 3 Trial 1 Failure Time(seconds)

Variable Name:
BAXFTC31
SAS Label:
Cond 3 Trial 1 Failure Time(seconds)
English Text:
Number of Seconds:
Target:
Both males and females 40 YEARS - 150 YEARS
Hard Edits:
0 to 29
Code or Value Value Description Count Cumulative Skip to Item
0 to 26 Range of Values 53 53
. Missing 3131 3184

BAXPFC32 - Cond 3 Trial 2 Foam Pad Eyes Open

Variable Name:
BAXPFC32
SAS Label:
Cond 3 Trial 2 Foam Pad Eyes Open
English Text:
Feet together eyes open:
Target:
Both males and females 40 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Pass 25 25 BAXPFC41
2 Dnp(did not pass) 26 51
. Missing 3133 3184

BAXFTC32 - Cond 3 Trial 2 Failure Time(seconds)

Variable Name:
BAXFTC32
SAS Label:
Cond 3 Trial 2 Failure Time(seconds)
English Text:
Number of Seconds:
Target:
Both males and females 40 YEARS - 150 YEARS
Hard Edits:
0 to 29
Code or Value Value Description Count Cumulative Skip to Item
0 to 24 Range of Values 26 26
. Missing 3158 3184

BAXPFC41 - Cond 4 Trial 1 Foam Pad Eyes Closed

Variable Name:
BAXPFC41
SAS Label:
Cond 4 Trial 1 Foam Pad Eyes Closed
English Text:
Feet together eyes closed:
English Instructions:
Stand in this position with your eyes closed, facing the target for as long as you can or until I ask you to stop. First assume this position with your eyes open, and then close your eyes. Please do not talk once the test begins. "Begin now."
Target:
Both males and females 40 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Pass 1144 1144 End of Section
2 Dnp(did not pass) 1289 2433
. Missing 751 3184

BAXFTC41 - Cond 4 Trial 1 Failure Time(seconds)

Variable Name:
BAXFTC41
SAS Label:
Cond 4 Trial 1 Failure Time(seconds)
English Text:
Number of Seconds:
Target:
Both males and females 40 YEARS - 150 YEARS
Hard Edits:
0 to 29
Code or Value Value Description Count Cumulative Skip to Item
1 to 29 Range of Values 1289 1289
. Missing 1895 3184

BAXPFC42 - Cond 4 Trial 2 Foam Pad Eyes Closed

Variable Name:
BAXPFC42
SAS Label:
Cond 4 Trial 2 Foam Pad Eyes Closed
English Text:
Feet together eyes closed:
Target:
Both males and females 40 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Pass 328 328 End of Section
2 Dnp(did not pass) 932 1260
. Missing 1924 3184

BAXFTC42 - Cond 4 Trial 2 Failure Time(seconds)

Variable Name:
BAXFTC42
SAS Label:
Cond 4 Trial 2 Failure Time(seconds)
English Text:
Number of Seconds:
Target:
Both males and females 40 YEARS - 150 YEARS
Hard Edits:
0 to 29
Code or Value Value Description Count Cumulative Skip to Item
0 to 29 Range of Values 926 926
. Missing 2258 3184