Carried Weight Affects Walking Speed Monitoring with the IngVaL System.

Earlier work has shown that the IngVaL pedobarography system can estimate walking speed during indoor walking using only three forefoot sensors. The aim of this study was to examine if monitoring of walking speed using data from these three forefoot sensors is affected of the weight a person carries, if the person performs a walk in a set speed on the treadmill. Shoe insoles with force sensing resistors were connected to an electronic unit for signal conditioning and sampling and then the data was sent via Bluetooth to a tablet. Fifteen test persons walked five times each carrying five different weights on the treadmill at 1 m/s. The force-time integrals for the sum of the three forefoot sensors were calculated. This study shows that the force-time integrals for the three forefoot sensors shows a linear relationship with the carried weight as long as the person is not fatigued.

Evaluation of the IngVaL Pedobarography System for Monitoring of Walking Speed.

OBJECTIVES: Walking speed is an important component of movement and is a predictor of health in the elderly. Pedobarography, the study of forces acting between the plantar surface of the foot and a supporting surface, is an approach to estimating walking speed even when no global positioning system signal is available. The developed portable system, Identifying Velocity and Load (IngVaL), is a cost effective alternative to commercially available pedobarography systems because it only uses three force sensing resistors. In this study, the IngVaL system was evaluated. The three variables investigated in this study were the sensor durability, the proportion of analyzable steps, and the linearity between the system output and the walking speed. METHODS: Data was collected from 40 participants, each of whom performed five walks at five different self-paced walking speeds. The linearity between the walking speed and step frequency measured with R2 values was compared for the walking speed obtained 'A' only using amplitude data from the force sensors, 'B' that obtained only using the step frequency, and 'C' that obtained by combining amplitude data for each of the 40 test participants. RESULTS: Improvement of the wireless data transmission increased the percentage of analyzable steps from 83.1% measured with a prototype to 96.6% for IngVaL. The linearity comparison showed that the methods A, B, and C were accurate for 2, 15, and 23 participants, respectively. CONCLUSIONS: Increased sensor durability and a higher percentage of analyzed steps indicates that IngVaL is an improvement over the prototype system. The combined strategy of amplitude and step frequency was confirmed as the most accurate method.

Walking Intensity Estimation with a Portable Pedobarography System.

The aim of this pilot study was to investigate the possibility to find a correlation between the output from a portable pedobarography system and the walking intensity expressed as walking speed. The system uses shoe insoles with force sensing resistors and wireless transmission of the data via Bluetooth. The force-time integral, at the toe-off phase of the step, for the force sensors in the forward part of the right foot was used to measure impulse data for 10 subjects performing walks in three different walking speeds. This data was then corrected by multiplication with the step frequency. This pilot study indicates that the portable pedobarography system output shows a linear relationship with the walking intensity expressed as walking speed on an individual level.

A study of hearing changes among military conscripts in the Swedish Army.

The aim of the study was to investigate the incidence and the relative risk of significant threshold shift (STS, >or=15 dB deterioration at any ear and audiometric frequency) during primary military service (7-9 months), and to investigate whether subjects with an initial slight hearing loss (thresholds>or=25 dB HL at any audiometric frequency and ear) were under increased risk. The investigation was made as a prospective audiometric study and included 747 men. An age-matched group of 138 individuals served as an unexposed control group, whose incidence of STS was 2.9%. In the exposed group the incidence was 7.9% and the relative risk 2.7 risk ratio (RR). In the subgroup of 95 persons, who already at reporting-for-training had a mild hearing loss, the incidence was 17%. The relative risk for STS in this group compared to the control group was 6.8 (RR), and compared to those with normal hearing at reporting was 3.1 (RR). In spite of hearing conservation efforts, hearing deterioration still occurs, above all in the artillery. Those who already at reporting-for-training had a mild hearing loss were at higher risk for STS compared to those with initially normal hearing.

High risk of sensorineural hearing loss in men born small for gestational age with and without obesity or height catch-up growth: a prospective longitudinal register study on birth size in 245,000 Swedish conscripts.

BACKGROUND: Several components of the metabolic syndrome coincide with those risk factors linked to sensorineural hearing loss (SNHL). According to the thrifty phenotype hypothesis, the metabolic syndrome can be caused by events during the fetal period. This study tests the thrifty phenotype hypothesis on hearing, using body size at birth and conscription as indirect markers for fetal programming and body mass index as an indicator for the metabolic syndrome. METHODS: Odds ratios were used to analyze birth data regarding body size from birth to conscription as risk factors for hearing loss in 245,092 conscripted Swedish men. FINDINGS: Compared with conscripts born short for gestational age with catch-up growth, those born short with absence of catch-up growth exhibited 134% higher risk of SNHL. Adult short stature was associated with a 50% increased risk. Compared with conscripts with average body mass index, overweight was associated with 30%, obesity with 99%, and overweight if born light for gestational age with 118% higher risk of SNHL. Conscripts born light for gestational age had a 41% increased risk, independent of the later growth pattern. CONCLUSION: The thrifty phenotype hypothesis also seems to be valid for SNHL, meaning that SNHL in adulthood may originate from events during fetal life. SNHL might be a new clinical feature of the metabolic syndrome.