02964nas a2200193 4500008004100000022001400041245014000055210006900195260001600264300000700280490000600287520232100293100002302614700002102637700002902658700002002687700002802707856003502735 2005 eng d a1743-000300aToo much or too little step width variability is associated with a fall history in older persons who walk at or near normal gait speed.0 aToo much or too little step width variability is associated with c2005 Jul 26 a210 v23 a

BACKGROUND: Decreased gait speed and increased stride time, stride length, double support time, and stance time variability have consistently been associated with falling whereas step width variability has not been strongly related to falls. The purpose was to examine the linear and nonlinear associations between gait variability and fall history in older persons and to examine the influence of gait speed.

METHODS: Gait characteristics and fall history were obtained in 503 older adults (mean age = 79; 61% female) participating in the Cardiovascular Health Study who could ambulate independently. Gait characteristics were recorded from two trials on a 4 meter computerized walkway at the subject's self-selected walking speed. Gait variability was calculated as the coefficient of variation. The presence of a fall in the past 12 months was determined by interview. The nonlinear association between gait variability and fall history was examined using a simple three level classification derived from the distribution of the data and from literature based cut-points. Multivariate logistic regression was used to examine the association between step width variability (extreme or moderate) and fall history stratifying by gait speed (1.0 m/s) and controlling for age and gender.

RESULTS: Step length, stance time, and step time variability did not differ with respect to fall history (p > .33). Individuals with extreme step width variability (either low or high step width variability) were more likely to report a fall in the past year than individuals with moderate step width variability. In individuals who walked > or = 1.0 m/s (n = 281), after controlling for age, gender, and gait speed, compared to individuals with moderate step width variability individuals with either low or high step width variability were more likely to have fallen in the past year (OR and 95% CI 4.38 [1.79-10.72]). The association between step width variability and fall history was not significant in individuals who walked < 1.0 m/s (n = 224).

CONCLUSION: Extreme (either too little or too much) step width variability is associated with falls in the past year in older persons who walk at or near normal gait speed and not in older persons who walk slowly (< 1.0 m/s).

1 aBrach, Jennifer, S1 aBerlin, Jaime, E1 aVanSwearingen, Jessie, M1 aNewman, Anne, B1 aStudenski, Stephanie, A uhttps://chs-nhlbi.org/node/84702748nas a2200349 4500008004100000022001400041245010200055210006900157260001300226300001000239490000700249520177800256653000902034653002202043653001002065653001902075653001102094653000902105653003102114653001102145653000902156653002402165653002402189653001702213653001202230100002302242700002802265700002102293700002902314700002002343856003502363 2007 eng d a1079-500600aGait variability and the risk of incident mobility disability in community-dwelling older adults.0 aGait variability and the risk of incident mobility disability in c2007 Sep a983-80 v623 a

BACKGROUND: Gait speed is a strong predictor of incident walking disability. The objective was to determine if gait variability adds to the prediction of incident mobility disability independent of gait speed.

METHODS: Participants included 379 older adults (mean age = 79 years; 78% Caucasian, and 40% men) in the Cardiovascular Health Study at the Pittsburgh site. All could ambulate independently and reported no difficulty walking a half mile. Gait characteristics were determined from a 4-meter computerized walkway. For each gait parameter, variability was defined as the standard deviation from the individual steps from two passes. Incident walking disability was obtained by phone interview every 6 months for 54 months and was defined as new difficulty walking a half mile or inability to walk a half mile.

RESULTS: Of the 379 participants, 222 (58.6%) developed incident mobility disability. In unadjusted Cox proportional hazards models gait speed, mean step length, mean stance time, and stance time variability were associated with incident mobility disability. After adjusting for gait speed, demographics, chronic conditions, prescription medications, health status, and physical activity level, only stance time variability remained an important indicator of disability. In the adjusted model, an increase in stance time variability of 0.01 seconds was associated with a 13% higher incidence of mobility disability (hazard ratio 1.13, 95% confidence interval, 1.01-1.27).

CONCLUSIONS: Stance time variability is an independent predictor of future mobility disability. Future efforts are needed to determine whether interventions that decrease stance time variability will also delay mobility disability.

10aAged10aAged, 80 and over10aAging10aCohort Studies10aFemale10aGait10aGait Disorders, Neurologic10aHumans10aMale10aMobility Limitation10aProspective Studies10aRisk Factors10aWalking1 aBrach, Jennifer, S1 aStudenski, Stephanie, A1 aPerera, Subashan1 aVanSwearingen, Jessie, M1 aNewman, Anne, B uhttps://chs-nhlbi.org/node/98702954nas a2200361 4500008004100000022001400041245007400055210006900129260001300198300001200211490000700223520196300230653000902193653002002202653001402222653002802236653002202264653001102286653000902297653002502306653001802331653001102349653001802360653002502378653000902403653003302412653002002445100002302465700002402488700002402512700002002536856003602556 2008 eng d a1538-672400aDiabetes mellitus and gait dysfunction: possible explanatory factors.0 aDiabetes mellitus and gait dysfunction possible explanatory fact c2008 Nov a1365-740 v883 a

BACKGROUND AND OBJECTIVE: Gait characteristics differ in individuals with diabetes compared with those without diabetes. Limited information regarding potential explanatory factors for this association exists. This study examined the association between diabetes and gait characteristics in older adults and explored potential explanatory factors.

DESIGN: A cross-sectional, observational study design was used.

METHODS: At the 1998-1999 clinic visit, 558 ambulatory older adults (mean age=79 years) from the Pittsburgh site of the Cardiovascular Health Study had an assessment of their gait characteristics, diabetes, health status, cognition, mood, lower-extremity circulation and sensation, vision, lower-extremity strength (force-producing capacity), physical activity, and body mass index (BMI). A series of linear regression models were developed to examine the association between diabetes and gait characteristics and to examine potential explanatory factors for the associations.

RESULTS: Diabetes was related to gait speed (beta=-.06 m/s); however, the association was partially explained by health status variables, cognition, mood, lower-extremity circulation and sensation, visual impairment, lower-extremity strength, physical activity, and BMI. Health status and lower-extremity strength each explained the greatest proportion of the association (beta reduced 66% by each). Diabetes was related to step width (beta=.02 m), and the association could not be explained by the examined factors.

CONCLUSIONS: Diabetes was associated with gait alterations in older adults. Slowed gait speed appears to be secondary to the peripheral effect of the disease on other body systems. The effect of diabetes on step width was not explained in the analyses and may be related to peripheral motor nerve function or central influences of the disease, which could not be assessed in this study.

10aAged10aBody Mass Index10aCognition10aCross-Sectional Studies10aDiabetes Mellitus10aFemale10aGait10aGeriatric Assessment10aHealth Status10aHumans10aLinear Models10aLongitudinal Studies10aMale10aMulticenter Studies as Topic10aMuscle Strength1 aBrach, Jennifer, S1 aTalkowski, Jaime, B1 aStrotmeyer, Elsa, S1 aNewman, Anne, B uhttps://chs-nhlbi.org/node/105202841nas a2200385 4500008004100000022001400041245014000055210006900195260001300264300001200277490000700289520173200296653002102028653000902049653002202058653002302080653002802103653001102131653000902142653002502151653001802176653001102194653000902205653001902214653002602233653001502259653002102274653002002295653001202315100002402327700002302351700002502374700002002399856003602419 2008 eng d a1538-672400aImpact of health perception, balance perception, fall history, balance performance, and gait speed on walking activity in older adults.0 aImpact of health perception balance perception fall history bala c2008 Dec a1474-810 v883 a

BACKGROUND AND PURPOSE: Disagreement currently exists regarding the contributions of various factors to physical activity in older adults. The purpose of this cross-sectional study was to investigate the simultaneous impact of psychological (health perception and balance perception) and physiological (gait speed, fall history, and balance performance) factors on walking activity in older adults.

SUBJECTS AND METHODS: This cross-sectional secondary data analysis included 2,269 community-dwelling older adults from the Cardiovascular Health Study. A series of simultaneous linear regression models were constructed to examine the association of walking activity with health and balance perception, gait speed, fall history, and balance performance after controlling for potential confounding factors.

RESULTS: Health and balance perception and gait speed were significantly related to walking activity after controlling for potential confounding factors. Participants who perceived both their health and their balance to be good walked more blocks per week than those who reported a discordant perception, who walked more than those who perceived both their health and their balance to be poor. Participants who walked at a normal speed walked more blocks per week than those who walked at a slow speed.

DISCUSSION AND CONCLUSION: The measure of physical activity used in this study included only walking, not other low- to moderate-intensity activities that are common in older adults. Health and balance perception and gait speed were associated with walking activity more so than fall history or balance performance after controlling for potential confounding factors.

10aAccidental Falls10aAged10aAged, 80 and over10aAttitude to Health10aCross-Sectional Studies10aFemale10aGait10aGeriatric Assessment10aHealth Status10aHumans10aMale10aMotor Activity10aMultivariate Analysis10aPerception10aPostural Balance10aRisk Assessment10aWalking1 aTalkowski, Jaime, B1 aBrach, Jennifer, S1 aStudenski, Stephanie1 aNewman, Anne, B uhttps://chs-nhlbi.org/node/105803343nas a2200457 4500008004100000022001400041245012900055210006900184260001300253300001200266490000700278520198400285653003102269653000902300653002802309653001902337653001602356653002602372653001102398653000902409653002502418653001102443653002002454653000902474653002402483653003302507653003202540653002002572653001702592653001802609100002302627700001702650700002402667700002402691700002102715700002502736700002102761700002002782710004702802856003602849 2008 eng d a1532-541500aIncident physical disability in people with lower extremity peripheral arterial disease: the role of cardiovascular disease.0 aIncident physical disability in people with lower extremity peri c2008 Jun a1037-440 v563 a

OBJECTIVES: To evaluate the risk of incident physical disability and the decline in gait speed over a 6-year follow-up associated with a low ankle-arm index (AAI) in older adults.

DESIGN: Observational cohort study.

SETTING: Forsyth County, North Carolina; Sacramento County, California; Washington County, Maryland; and Allegheny County, Pennsylvania.

PARTICIPANTS: Four thousand seven hundred five older adults, 58% women and 17.6% black, participating in the Cardiovascular Health Study.

MEASUREMENTS: AAI was measured in 1992/93 (baseline). Self-reported mobility, activity of daily living (ADL), and instrumental activity of daily living (IADL) disability and gait speed were recorded at baseline and at 1-year intervals over 6 years of follow-up. Mobility disability was defined as any difficulty walking half a mile and ADL and IADL disability was defined as any difficulty with 11 specific ADL and IADL tasks. Individuals with mobility, ADL, or IADL disability at baseline were excluded from the respective incident disability analyses.

RESULTS: Lower baseline AAI values were associated with increased risk of mobility disability and ADL/IADL disability. Clinical cardiovascular disease (CVD), diabetes mellitus, and interim CVD events partially explained these associations for mobility disability and clinical CVD and diabetes mellitus partially explained these associations for ADL and IADL disability. Individuals with an AAI less than 0.9 had on average a mean decrease in gait speed of 0.02 m/s per year, or a decline of 0.12 m/s over the 6-year follow-up. Prevalent CVD partly explained this decrease but interim CVD events did not further attenuate it.

CONCLUSION: Low AAI serves as marker of future disability risk. Reduction of disability risk in patients with a low AAI should consider cardiovascular comorbidity and the prevention of additional disabling CVD events.

10aActivities of Daily Living10aAged10aCardiovascular Diseases10aCohort Studies10aComorbidity10aDisability Evaluation10aFemale10aGait10aGeriatric Assessment10aHumans10aLower Extremity10aMale10aMobility Limitation10aPeripheral Vascular Diseases10aProportional Hazards Models10aRisk Assessment10aRisk Factors10aUnited States1 aBrach, Jennifer, S1 aSolomon, Cam1 aNaydeck, Barbara, L1 aSutton-Tyrrell, Kim1 aEnright, Paul, L1 aJenny, Nancy, Swords1 aChaves, Paulo, M1 aNewman, Anne, B1 aCardiovascular Health Study Research Group uhttps://chs-nhlbi.org/node/102402434nas a2200337 4500008004100000022001400041245010100055210006900156260001300225300001100238490000700249520148300256653003101739653000901770653002801779653002601807653001301833653001101846653000901857653001801866653001101884653000901895653001701904653001901921653003101940100002301971700002101994700002502015700002002040856003602060 2008 eng d a1532-821X00aThe reliability and validity of measures of gait variability in community-dwelling older adults.0 areliability and validity of measures of gait variability in comm c2008 Dec a2293-60 v893 a

OBJECTIVE: To examine the test-retest reliability and concurrent validity of variability of gait characteristics.

DESIGN: Cross-sectional study.

SETTING: Research laboratory.

PARTICIPANTS: Older adults (N=558) from the Cardiovascular Health Study.

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: Gait characteristics were measured using a 4-m computerized walkway. SD determined from the steps recorded were used as the measures of variability. Intraclass correlation coefficients (ICC) were calculated to examine test-retest reliability of a 4-m walk and two 4-m walks. To establish concurrent validity, the measures of gait variability were compared across levels of health, functional status, and physical activity using independent t tests and analysis of variances.

RESULTS: Gait variability measures from the two 4-m walks demonstrated greater test-retest reliability than those from the single 4-m walk (ICC=.22-.48 and ICC=.40-.63, respectively). Greater step length and stance time variability were associated with poorer health, functional status and physical activity (P<.05).

CONCLUSIONS: Gait variability calculated from a limited number of steps has fair to good test-retest reliability and concurrent validity. Reliability of gait variability calculated from a greater number of steps should be assessed to determine if the consistency can be improved.

10aActivities of Daily Living10aAged10aCross-Sectional Studies10aDisability Evaluation10aExercise10aFemale10aGait10aHealth Status10aHumans10aMale10aPennsylvania10aRehabilitation10aReproducibility of Results1 aBrach, Jennifer, S1 aPerera, Subashan1 aStudenski, Stephanie1 aNewman, Anne, B uhttps://chs-nhlbi.org/node/106502899nas a2200361 4500008004100000022001400041245009800055210006900153260001300222300001000235490000700245520182900252653000902081653002202090653002802112653001102140653003102151653001102182653001802193653002502211653000902236653002902245653002102274653003102295653001702326653004102343100002302384700002502407700002102432700002902453700002002482856003502502 2008 eng d a0966-636200aStance time and step width variability have unique contributing impairments in older persons.0 aStance time and step width variability have unique contributing  c2008 Apr a431-90 v273 a

Gait variability may have multiple causes. We hypothesized that central nervous system (CNS) impairments would affect motor control and be manifested as increased stance time and step length variability, while sensory impairments would affect balance and be manifested as increased step width variability. Older adults (mean+/-standard deviation (S.D.) age=79.4+/-4.1, n=558) from the Pittsburgh site of the Cardiovascular Health Study participated. The S.D. across steps was the indicator of gait variability, determined for three gait measures, step length, stance time and step width, using a computerized walkway. Impairment measures included CNS function (modified mini-mental state examination, Trails A and B, Digit Symbol Substitution, finger tapping), sensory function (lower extremity (LE) vibration, vision), strength (grip strength, repeated chair stands), mood, and LE pain. Linear regression models were fit for the three gait variability characteristics using impairment measures as independent variables, adjusted for age, race, gender, and height. Analyses were repeated stratified by gait speed. All measures of CNS impairment were directly related to stance time variability (p<0.01), with increased CNS impairment associated with increased stance time variability. CNS impairments were not related to step length or width variability. Both sensory impairments were inversely related to step width (p<0.01) but not step length or stance time variability. CNS impairments affected stance time variability especially in slow walkers while sensory impairments affected step width variability in fast walkers. Specific patterns of gait variability may imply different underlying causes. Types of gait variability should be specified. Interventions may be targeted at specific types of gait variability.

10aAged10aAged, 80 and over10aBiomechanical Phenomena10aFemale10aGait Disorders, Neurologic10aHumans10aLinear Models10aLongitudinal Studies10aMale10aNeuropsychological Tests10aPostural Balance10aRange of Motion, Articular10aRisk Factors10aSignal Processing, Computer-Assisted1 aBrach, Jennifer, S1 aStudenski, Stephanie1 aPerera, Subashan1 aVanSwearingen, Jessie, M1 aNewman, Anne, B uhttps://chs-nhlbi.org/node/97003468nas a2200361 4500008004100000022001400041245012800055210006900183260001700252300001000269490000700279520239100286653000902677653002202686653002602708653001102734653000902745653002502754653001102779653002302790653000902813653002402822653003202846653002102878653002402899653003102923100002302954700001602977700002902993700002003022700002803042856003603070 2012 eng d a2152-089500aUse of stance time variability for predicting mobility disability in community-dwelling older persons: a prospective study.0 aUse of stance time variability for predicting mobility disabilit c2012 Jul-Sep a112-70 v353 a

BACKGROUND AND PURPOSE: Mobility disability is a serious and frequent adverse health outcome associated with aging. Early identification of individuals at risk for mobility disability is important if interventions to prevent disability are to be instituted. The objectives of this prospective study were to (1) determine the magnitude of stance time variability (STV) that discriminates individuals who currently have mobility disability (prevalent mobility disability) and (2) determine the magnitude of STV that predicts a new onset of mobility disability at 1 year (incident mobility disability).

METHODS: A total of 552 community-dwelling older adults were evaluated as part of the Cardiovascular Health Study, a longitudinal cohort study. Stance time, in milliseconds, was determined from 2 passes on a 4-m computerized walkway at self-selected walking speed, and STV was defined as the standard deviation from approximately 12 individual steps. Mobility disability was defined as self-reported difficulty walking a one-half mile. Receiver operating characteristic (ROC) curves were plotted to determine an optimal cutoff value for STV for prevalent and incident mobility disability, and the area under the receiver operating characteristic curve (AUC) was computed.

RESULTS: The optimal cutoff score for STV (maximizing sensitivity and specificity) for prevalent mobility disability was 0.037 seconds (sensitivity = 65%, specificity = 65%, AUC = 0.70) and for incident 1-year mobility disability was 0.034 seconds (sensitivity = 61%, specificity = 60%, AUC = 0.65). The use of likelihood ratios demonstrated a gradient of risk across values of STV, with mobility risk increasing as values of STV increased.

DISCUSSION AND CONCLUSION: Values of STV may be useful in identifying older adults with mobility disability and at risk for future disability. We recommend the more conservative estimate for identifying risk, STV = 0.034 seconds, which maximizes the sensitivity and minimizes false negatives. The relatively modest values on the validity indices could possibly be improved by increasing the reliability of the measurement of STV. Clinicians should interpret the cutoff values liberally and use STV in conjunction with other measures until further work is completed to validate STV as an indicator of mobility disability.

10aAged10aAged, 80 and over10aDisability Evaluation10aFemale10aGait10aGeriatric Assessment10aHumans10aIndependent Living10aMale10aMobility Limitation10aPhysical Therapy Modalities10aPostural Balance10aProspective Studies10aReproducibility of Results1 aBrach, Jennifer, S1 aWert, David1 aVanSwearingen, Jessie, M1 aNewman, Anne, B1 aStudenski, Stephanie, A uhttps://chs-nhlbi.org/node/136302568nas a2200241 4500008004100000022001400041245010600055210006900161260001600230520182300246100002202069700002402091700001702115700002102132700002302153700001602176700002002192700001802212700002102230700001802251700002102269856003602290 2024 eng d a1758-535X00aAssociations of Neurological Biomarkers in Serum with Gait Measures: The Cardiovascular Health Study.0 aAssociations of Neurological Biomarkers in Serum with Gait Measu c2024 Feb 093 a

BACKGROUND: Gait impairment leads to increased mobility decline and may have neurological contributions. This study explores how neurological biomarkers are related to gait in older adults.

METHODS: We studied participants in the Cardiovascular Health Study, a population-based cohort of older Americans, who underwent a serum biomarker assessment from samples collected in 1996-97 for neurofilament light-chain (NfL), glial fibrillary acidic protein (GFAP), ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), and total tau (n=1959, mean age=78.0 years, 60.8% female). In a subsample (n=380), cross-sectional associations with quantitative gait measures were explored. This subsample was assessed on a mat for gait speed, step length, double support time, step time, step length variability and step time variability. Gait speed was also measured over a 15-ft walkway annually from 1996-97 to 1998-99, for longitudinal analyses. Linear regression models assessed cross-sectional associations of biomarkers with gait measures, while mixed effects models assessed longitudinal gait speed change from baseline to 1998-99.

RESULTS: NfL was significantly associated with annual gait speed decline (standardized β = -0.64 m/s, 95% CI: [-1.23, -0.06]) after adjustment for demographic and health factors. Among gait mat-assessed phenotypes, NfL was also cross-sectionally associated with gait speed (β = 0.001 m/s [0.0003, 0.002]) but not with other gait measures. None of the remaining biomarkers were significantly related to gait in either longitudinal or cross-sectional analyses.

CONCLUSION: Higher NfL levels were related to greater annual gait speed decline. Gait speed decline may be related to axonal degeneration. The clinical utility of NfL should be explored.

1 aNadkarni, Abhijay1 aMukamal, Kenneth, J1 aZhu, Xiaonan1 aSiscovick, David1 aBrach, Jennifer, S1 aJacob, Mini1 aSeshadri, Sudha1 aAbe, Temidayo1 aRosano, Caterina1 aDjoussé, Luc1 aRosso, Andrea, L uhttps://chs-nhlbi.org/node/9614