The Coefficient of Variation of Step Time Can Overestimate Gait Abnormality: Test-Retest Reliability of Gait-Related Parameters Obtained with a Tri-Axial Accelerometer in Healthy Subjects

Abstract

The aim of this study was to investigate whether variation in gait-related parameters among healthy participants could help detect gait abnormalities. In total, 36 participants (21 men, 15 women; mean age, 35.7 ± 9.9 years) performed a 10-m walk six times while wearing a tri-axial accelerometer fixed at the L3 level. A second walk was performed ≥1 month after the first (mean interval, 49.6 ± 7.6 days). From each 10-m data set, the following nine gait-related parameters were automatically calculated: assessment time, number of steps, stride time, cadence, ground force reaction, step time, coefficient of variation (CV) of step time, velocity, and step length. Six repeated measurement values were averaged for each gait parameter. In addition, for each gait parameter, the difference between the first and second assessments was statistically examined, and the intraclass correlation coefficient (ICC) was calculated with the level of significance set at p < 0.05. Only the CV of step time showed a significant difference between the first and second assessments (p = 0.0188). The CV of step time also showed the lowest ICC, at <0.50 (0.425), among all parameters. Test–retest results of gait assessment using a tri-axial accelerometer showed sufficient reproducibility in terms of the clinical evaluation of all parameters except the CV of step time.

Investigating Gait, Movement, and Coordination in Children with Neurodevelopmental Disorders: Is There a Role for Motor Abnormalities in Atypical Neurodevelopment?

“…When assessing gait outcome, step time was considered of particular interest, as it is one of the most investigated measures in neurodevelopment [ 34 ] and evidence suggests it to be a specific indicator of gait patterning [ 36 ], while other measures may be more useful when assessing functional performance (e.g., velocity) [ 40 ] or equilibrium (e.g., support phases) [ 41 ]. Moreover, along with cadence, step time has been recently suggested to be the most robust parameter in terms of reproducibility, showing good intraclass correlation coefficient, and yielding a false positive in terms of gait deficits less likely [ 35 ]. By contrast, other parameters (e.g., velocity, step length) may change depending on the condition and/or intention of the subjects participating in the gait measurement, significantly increasing the chances of yielding a false-positive result [ 35 ].…”

“…Moreover, along with cadence, step time has been recently suggested to be the most robust parameter in terms of reproducibility, showing good intraclass correlation coefficient, and yielding a false positive in terms of gait deficits less likely [ 35 ]. By contrast, other parameters (e.g., velocity, step length) may change depending on the condition and/or intention of the subjects participating in the gait measurement, significantly increasing the chances of yielding a false-positive result [ 35 ].…”

“…In light of the lack of empirical studies systematically examining motor function across different neuropsychiatric conditions, especially NDD, the present study attempted to fill this gap by conducting a comprehensive assessment of motor abilities across different domains such as gait, movement, and coordination, in a group of young individuals with NDD as compared to a group of healthy controls. We hypothesized that NDD individuals would present with poorer motor functioning than healthy controls in terms of (i) less proficient spatiotemporal gait organization, indexed by an increased step time as the most investigated [ 34 ] and reliable [ 35 ] measure of less efficient gait patterning [ 36 ]; (ii) less proficient motor skills, indexed by a lower total score at the Movement Assessment Battery for Children, 2nd edition (M-ABC-2) [ 37 ]; and (iii) less proficient coordination, indexed by a lower total score at the Developmental Coordination Disorder Questionnaire, as revised in 2007 (DCDQ’07) [ 38 ]. Furthermore, we conducted exploratory analyses in order to investigate whether any socio-demographic or clinical characteristics would concur with anomalies in motor functioning to distinguish NDD individuals from healthy controls, especially male gender and dysfunctional neurocognition which are known to play a key role in atypical development [ 13 ].…”

Comparison of Subjective and Objective Assessments on Improvement in Gait Function after Carotid Endarterectomy

“…), who was blinded to postoperative subjective assessments of gait, objectively and quantitatively assessed gait function using a tri-axial accelerometer (MG-M1110-HW; LSI Medience, Tokyo, Japan) in the same manner as described previously [ 19 ]. This accelerometer can measure tri-axial (vertical, anteroposterior, and mediolateral) acceleration by detecting limb and trunk movements at a sampling rate of 100 Hz during step-in and kick-off motions [ 19 ]. For each patient, the accelerometer was fixed at the L3 level of the spine with a nylon belt.…”

“…These devices have now been applied in clinical studies [ 13 , 14 , 15 , 16 , 17 , 18 ]. In addition, the reliability of gait-related parameters obtained from tri-axial accelerometers has been confirmed with test-retest measurements [ 19 ].…”