Validity and reliability of Eforto®, a system to (self-)monitor grip strength and muscle fatigability in older persons.

INTRODUCTION: We developed Eforto®, an innovative system for (self-)monitoring of grip strength (GS) and muscle fatigability (Fatigue Resistance (FR = time until GS decreased to 50% of maximum during sustained contraction) and grip work (GW = area under the strength-time curve)). The Eforto® system consists of a rubber bulb that is wirelessly connected to a smartphone-based application, and a telemonitoring platform. The aim was to evaluate the validity and reliability of Eforto® to measure muscle fatigability. METHODS: Community-dwelling older persons (n = 61), geriatric inpatients (n = 26) and hip fracture patients (n = 25) were evaluated for GS and muscle fatigability. In community dwellers fatigability was tested twice in the clinic (once with Eforto®, once with Martin Vigorimeter (MV), standard analog handgrip system) and for six consecutive days as a self-assessment at home with Eforto®. In hospitalized participants, fatigability was tested twice using Eforto®, once by a researcher and once by a health professional. RESULTS: Criterion validity was supported by good to excellent correlations between Eforto® and MV for GS (r = 0.95) and muscle fatigability (FR r = 0.81 and GW r = 0.73), and no significant differences in measurements between both systems. Inter-rater and intra-rater reliability for GW were moderate to excellent (intra-class correlation: 0.59-0.94). The standard error of measurement for GW was small for geriatric inpatients and hip fracture patients (224.5 and 386.5 kPa*s) and higher for community-dwellers (661.5 kPa*s). DISCUSSION/CONCLUSION: We established the criterion validity and reliability of Eforto® in older community-dwelling persons and hospitalized patients, supporting the implementation of Eforto® for (self-)monitoring of muscle fatigability.

The reliability of a frailty index may depend on the deficits included.

PURPOSE: Recently, a short version of the TOPICS-MDS questionnaire, the Short Form (SF) was developed. The aim of this study was to assess the validity and reliability of two versions of a frailty index (FI) based on this SF: with or without information on present diseases included. METHODS: This was a clinical, prospective study of geriatric patients. An FI based on the TOPICS-SF items alone (SF-FI) and an FI with the disease information as additional deficits (MDS-FI) were calculated. Criterion and construct validity and reliability were assessed. RESULTS: 95 patients were included. A strong correlation was found between SF-FI and MDS-FI scores (Pearson's r = 0.92). Data supported four out of six hypotheses for the construct validity. However, a Bland-Altman plot and a regression analysis showed that the SF-FI was generally higher than the MDS-FI. CONCLUSION: This study indicates that the reliability of the TOPICS-SF-FI depends on the presence of disease information.