Comparison of Step Length Estimators from Weareable Accelerometer Devices

Álvarez, Diego; Gonzalez, R. C.; López, Antonio M.; Álvarez, Juan C.

doi:10.1109/iembs.2006.259593

Cited by 114 publications

(54 citation statements)

References 10 publications

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“…the result from the first integration) is zero and vertical coordinate of the COM (i.e. after second integration) is the same that at the beginning of the step [73].…”

Section: Gait Parametersmentioning

confidence: 91%

“…In the deceleration stage, in turn, the decrease in body inclination leads to higher vertical accelerations [50]. As can be observed in Figure 2.21, the first valley will correspond to a heel contact and the second valley to final contact of the same foot [72,73]. After heel contact, a rapid upward acceleration is observed [71].…”

Section: Sensors Signal Analysismentioning

confidence: 93%

“…Later, in 2006, Alvarez et al (2006) conducted a study where different step length estimators using wearable devices were compared [73]. The majority of the methods described included constants that required a calibration process, which had to be performed for each individual and was time consuming.…”

Section: Gait Parametersmentioning

confidence: 99%

“…The minimums after heel strikes were considered the toe offs [73]. To detect these instants, the samples after a foot contact were evaluated.…”

Section: Toe Offs Detectionmentioning

confidence: 99%

“…Zijlstra (2004) referred the use of a 4th order zero-lag Butterworth filter in order to avoid integration drift on position data [45]. Alvarez et al (2006) refers a more tricky process in order to avoid drift, which is to force the final values of the integrals to be the desired ones, having in mind that at the time of foot-flat the velocity (i.e. the result from the first integration) is zero and vertical coordinate of the COM (i.e.…”

Section: Gait Parametersmentioning

confidence: 99%

See 4 more Smart Citations

Phone Based Fall Risk Prediction

Guimar�ães

Teixeira

Monteiro

et al. 2012

Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering

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Falls in older people can represent serious individual and socioeconomic problems. With the increasing number of older people in the population, management of falls is becoming a challenge.It is now recognized that several risk factors for falling can be identified, and specific interventions can be designed in order to reduce those risks. Several tools were then developed and are now available to screen for fall risk. However, these tools are applied with low frequency, usually requiring the use of expensive equipments that can only be manipulated by experts. This poses some constraints on the prevention of falls, since when these techniques are applied, it can be too late.In order to improve the earlier detection of risks and the application of fall prevention strategies, new community based solutions must be developed. In this project, the mobile phone was purposed as a potential instrument to perform fall risk screening. Several strategies were then evaluated to be adapted to the phone for fall risk screening purposes.Phone's inertial sensors were used to extract some parameters of gait that were related with an increased risk of falling. Foot contacts, gait phases, step length, step duration, walking velocity and variability parameters could then be determined from sensors data. Acceptable measures of step length and walking velocity could be obtained. Additionally, other risk factors were selected to be assessed by self-report, using some clinical scales/questionnaires.Results suggest that phone can be used as a major strategy to improve fall prevention, being a great value for older persons and society.i ii ResumoUma queda num idoso pode resultar em graves problemas individuais e socioeconómicos. Com o aumento do número de idosos na população, a gestão de quedas está a tornar-se um desafio.Actualmente, é possível identificar vários factores de risco para a ocorrência de quedas bem como reduzir esses riscos, através da aplicação da aplicação de intervenções especí-ficas. Nesse sentido, há já algumas ferramentas actualmente disponíveis para avaliar o risco de queda. Estas ferramentas no entanto usadas com baixa frequência, exigindo o uso de equipamentos caros que apenas podem ser manipulados por pessoas qualificadas. Muitas vezes, estas técnicas podem já ser aplicadas tarde demais.Para que a detecção dos riscos e a aplicação de estratégias de prevenção de quedas possa ser feita mais precocemente, é necessário o desenvolvimento de novas soluções dirigidas à população. Neste projecto, foi proposto o uso do telemóvel para a detecção do risco de queda nos idosos.Os sinais dos sensores do telemóvel foram utilizados para extrair parâmetros da marcha relacionados com um risco de queda aumentado. A partir deles, os contactos do pé com o chão, as fases da marcha, o tamanho e duração dos passos, a velocidade e parâmetros que quantificam a variabilidade da marcha puderam ser determinados. Medidas aceitáveis do tamanho dos passos e da velocidade foram obtidas. Adicionalmente, outros factores de risco foram sele...

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“…the result from the first integration) is zero and vertical coordinate of the COM (i.e. after second integration) is the same that at the beginning of the step [73].…”

Section: Gait Parametersmentioning

confidence: 91%

Section: Sensors Signal Analysismentioning

confidence: 93%