Table of Contents

Locator Record

Title: Balance (BAX_C )
Contact Number: 1-866-441-NCHS
Years of Content: 2003 - 2004
First Published: December, 2005
Revised: NA
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject:Balance
Record Source: NHANES 2003 - 2004
Survey Methodology: NHANES 2003 - 2004 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, who are an increasing segment of the U.S. general population. For example, balance disorders are thought to be causally related to some 200,000 hip fractures that occur annually in Americans over the age of 65. The objectives of the Balance Component are

The NHANES 2003–2004 Balance Component consists of 2 parts:

  1. A pre-exam screening questionnaire. This is a series of questions that 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; and
  2. Balance Testing, consisting of a modified Romberg Test of Standing Balance on Firm and Complaint Support Surfaces.

Eligible Sample

The 2003–2004 Balance Component tested a full sample of U.S. adults 40 years of age and older. There were five principal exclusion criteria applied in the Balance testing protocol. These were:

  1. at the time of the exam, an examinee felt unable to stand on his or her own;
  2. at the time of the exam, an examinee was currently having dizziness sufficient to cause unsteadiness;
  3. weight over 275 lbs;
  4. an examinee needed a leg brace in order to stand unassisted;
  5. an examinee 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, as were those who had a waist circumference either too small or too large to accommodate proper fitting of any standard sized safety gait belt. Also, the Mobile Examination Center (MEC) physician could exclude subjects if it was considered medically contraindicated to perform testing.

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 Test Condition 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 his 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 and 4 conducted for 30 seconds each. Test failure was defined as:

In the standard Balance Testing protocol, each subject is eligible for an initial test and one re-test 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.

For the procedures relevant to this component, please refer to the Survey Operations Manual, Consent Documents, Brochures on the NHANES website.

Quality Assurance & Quality Control

All data from each of the sections of the Balance Component were directly entered by MEC technicians into ISIS, a computerized database information system. Technicians selected for the Mobile Examination Centers 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) and contractor staff provided performance monitoring of each Technician on a regular, periodic basis. Additionally, NCHS staff visited the MECs approximately twice per year to observe the Balance examinations and verify that standard testing procedures were being strictly followed by technicians. All MEC Balance technicians also received annual retraining and updates by the NIOSH consultants. Finally, exclusion rates and outcome statistics were continually monitored by NCHS statisticians according to technician and MEC, and retraining was conducted as necessary to maintain test quality.

For details on the QA/QC process for this component, please refer to the Interviewer Procedure Manuals on the NHANES website.

Data Processing and Editing

As mentioned previously, all data were captured in ISIS, a computerized database. NCHS statisticians performed data reviews on an ongoing basis using a computerized data editing program 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 where errors were detected. The 2003–2004 Balance Examination data were re-reviewed for errors and logical consistency and verified against the primary examination data database prior to public release.

Analytic Notes

Because the NHANES 2003–2004 Balance examination was administered in the MEC, the full sample MEC examination sample weight should be used for data analysis. For information on the use of sample weights in NHANES data analysis, refer to the NHANES 1999–2000 Addendum to the NHANES III Analytic Guidelines. Analysts who wish to combine Balance data from NHANES 1999–2000 with the NHANES 2001–2002 or 2003–2004 Balance examination data should be aware that the sampling frame for NHANES 1999–2000 Balance Examination data differed from that for the 2001–2004 Balance data. Specifically, NHANES 1999–2000 Balance data were collected for a one-half sample of U.S. adults ages 40–69 years, whereas NHANES 2001–2004 Balance was collected for a full sample of U.S. adults ages 40 and older. Special half-sample weights are available on the NHANES 1999–2000 Balance data set and are to be used when analyzing the data for those years. For combined 1999–2000 and 2001–2002 data analysis, special 4-year Balance subsample weights are provided (WTSBA4YR) on the 2001-2002 Balance dataset. Six-year data analysis (1999–2004) is performed by combining the 4-year Balance subsample weights with the 2003–2004 MEC examination weights according to the NHANES Analytic Guidelines.

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 and 2; 30 seconds for Conditions 3 and 4) may need to be taken into account for the analysis. The variable BAAEXCMT provides coded data summarizing the reasons that an examination was incomplete (partial) or not done.

Please refer to the Analytic Guidelines for further details on the use of sample weights and other analytic issues at http://www.cdc.gov/nchs/nhanes/survey_methods.htm.

No data related to this component are in the Research Data Center.

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

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 2429 2429
2 Partial 74 2503
3 Not done 583 3086
. Missing 0 3086

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 279 279
2 SP refusal 145 424
3 No time 6 430
4 Physical limitation 66 496
5 Communication problem 3 499
7 SP ill/emergency 8 507
72 Error (technician/software/supply) 1 508
84 SP With Child 12 520
99 Other, specify 137 657
. Missing 2429 3086

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 2650 2650
2 No 40 2690
. Missing 396 3086

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 16 16
2 No 2634 2650
. Missing 436 3086

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 131 131
2 No 2503 2634
. Missing 452 3086

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 2476 2476 BAXPFC21
2 Dnp(did not pass) 11 2487
. Missing 599 3086

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
2 to 13 Range of Values 11 11
. Missing 3075 3086

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 8 8 BAXPFC21
2 Dnp(did not pass) 3 11
. Missing 3075 3086

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 7 Range of Values 3 3
. Missing 3083 3086

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 2287 2287 BAXPFC31
2 Dnp(did not pass) 193 2480
. Missing 606 3086

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
1 to 14 Range of Values 193 193
. Missing 2893 3086

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 105 105 BAXPFC31
2 Dnp(did not pass) 88 193
. Missing 2893 3086

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
1 to 14 Range of Values 88 88
. Missing 2998 3086

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 2277 2277 BAXPFC41
2 Dnp(did not pass) 94 2371
. Missing 715 3086

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 28 Range of Values 93 93
. Missing 2993 3086

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 36 36 BAXPFC41
2 Dnp(did not pass) 47 83
. Missing 3003 3086

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 28 Range of Values 44 44
. Missing 3042 3086

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 884 884 End of Section
2 Dnp(did not pass) 1426 2310
. Missing 776 3086

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
0 to 29 Range of Values 1425 1425
. Missing 1661 3086

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 318 318 End of Section
2 Dnp(did not pass) 1095 1413
. Missing 1673 3086

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 1094 1094
. Missing 1992 3086