The French Aging Males' Symptoms (AMS) scale: Methodological review

BACKGROUND: The AMS is an internationally used health-related quality of life (HRQoL) scale. The aim of this paper is to provide evidence that the French AMS scale measures HRQoL are as valid as other language versions. We also intend to show whether the application of AMS is really limited to aging males only or not. More generally, we like to demonstrate that the AMS scale is a relevant, validated, sensitive instrument to measure HRQoL and change of symptoms in France. METHODS: We performed a representative survey in France to get data AMS scale data. The French data were compared with existing data from other European countries. Only community-based data were used for this comparison. RESULTS AND DISCUSSION: Reliability (here consistency, Cronbach' s alpha) was found to be good and almost identical with other countries. Validity: the internal structure of the AMS (factorial analysis) was sufficiently comparable with the comparison group of other countries in Europe to conclude that the scale really measures the same phenomenon. The sub-scores and total score correlations (Pearson) were high (r = 0.8–0.9) but only somewhat lower among the sub-scales (r = 0.5–0.7). This suggests that the domains are correlated. The comparison of the French AMS with the generic quality-of-life scale SF-12 showed a good correlation (Pearson r = 0.48 – 0.51) as reported from other countries. We observed also a good correlation between the AMS scale and the depression scale HAD (Pearson r = 0.62). The analysis of the AMS structure across age groups showed sufficient similarity to suggest that the AMS is also useful for younger age groups. CONCLUSION: The French AMS scale is a standardized HRQoL scale with good psychometric characteristics (reliability, validity) as shown for other international versions. We suggest that the AMS scale could be also used in age groups under 40 years to measure and compare HRQoL in males. Since the application of the AMS in younger age was not investigated before, confirmation in future studies is needed

The Aging Males' Symptoms (AMS) scale: review of its methodological characteristics

BACKGROUND: The current paper reviews data from different sources to get a closer impression on the psychometric and other methodological characteristics of the Aging Males' Symptoms (AMS) scale gathered recently. The scale was designed and standardized as self-administered scale to (a) to assess symptoms of aging (independent from those which are disease-related) between groups of males under different conditions, (b) to evaluate the severity of symptoms over time, and (c) to measure changes pre- and post androgen replacement therapy. The scale is in widespread use (14 languages). METHOD: Original data from different studies in many countries were centrally analysed to evaluate reliability and validity of the AMS. RESULTS: Reliability measures (consistency and test-retest stability) were found to be good across countries, although the sample size was sometimes small. Validity: The internal structure of the AMS in healthy and androgen deficient males, and across countries was sufficiently similar to conclude that the scale really measures the same phenomenon. The sub-scores and total score correlations were high (0.8–0.9) but lower among the sub-scales (0.5–0.7). This however suggests that the subscales are not fully independent. The comparison with other scales for aging males or screening instruments for androgen deficiency showed sufficiently good correlations, illustrating a good criterion-oriented validity. The same is true for the comparison with the generic quality-of-life scale SF36 where also high correlation coefficients have been shown. Methodological analyses of a treatment study of symptomatic males with testosterone demonstrated the ability of the AMS scale to measure treatment effect, irrespective of the severity of complaints before therapy. It was also shown that the AMS result can predict the independently generated (physician's) opinion about the individual treatment effect. CONCLUSION: The currently available methodological evidence points towards a high quality of the AMS scale to measure and to compare HRQoL of aging males over time or before/after treatment, it suggests a high reliability and high validity as far as the process of construct validation could be pressed ahead yet. But certainly more data will become available, particularly from ongoing clinical studies

The Aging Males' Symptoms (AMS) scale: Update and compilation of international versions

BACKGROUND: The interest of clinical research in aging males increased in recent years and thereby the interest to measure health-related quality of life (HRQoL) and symptoms of aging men. The Aging Males' Symptoms scale (AMS) became the most commonly used scale to measure HRQoL and symptoms in aging males in many countries worldwide. The aim of this paper is to review the current state of the instrument particularly concerning versions of the scale in different languages in the light of the quality of the translation process. AMS VERSIONS AVAILABLE: Most of the translations were performed following international methodological recommendations for linguistic & cultural adaptation of HRQoL instruments. Mainly the English version was used as source language for the translation into Dutch, Spanish, Portuguese, Italian, Swedish, and Japanese (attached as additional PDF-files). Preliminary versions that were derived only from forward translations are of secondary quality and available in Finnish, Flemish, and Russian. It is recommended to complete the translation process for the latter languages before using them in international studies. TRANSLATIONS IN PROCESS: The AMS scale is in the process of consensus finding of two existing French versions, and the versions in the Korean, Thai, and Indonesian languages have not yet been completed in the translation process. CONCLUSION: The AMS scale is obviously a valuable tool for assessing health related quality of life in aging men, because it is used worldwide. It is a standardized scale according to psychometric norms. Most of the currently available language versions were translated following international standards for linguistic and cultural translation of quality of life scales. Assistance is offered to help interested parties in the translation process

Reliable fault diagnosis for low-speed bearings using individually trained support vector machines with kernel discriminative feature analysis

This paper proposes a highly reliable fault diagnosis approach for low-speed bearings. The proposed approach first extracts wavelet-based fault features that represent diverse symptoms of multiple low-speed bearing defects. The most useful fault features for diagnosis are then selected by utilizing a genetic algorithm (GA)-based kernel discriminative feature analysis cooperating with one-against-all multicategory support vector machines (OAA MCSVMs). Finally, each support vector machine is individually trained with its own feature vector that includes the most discriminative fault features, offering the highest classification performance. In this study, the effectiveness of the proposed GA-based kernel discriminative feature analysis and the classification ability of individually trained OAA MCSVMs are addressed in terms of average classification accuracy. In addition, the proposedGA- based kernel discriminative feature analysis is compared with four other state-of-the-art feature analysis approaches. Experimental results indicate that the proposed approach is superior to other feature analysis methodologies, yielding an average classification accuracy of 98.06% and 94.49% under rotational speeds of 50 revolutions-per-minute (RPM) and 80 RPM, respectively. Furthermore, the individually trained MCSVMs with their own optimal fault features based on the proposed GA-based kernel discriminative feature analysis outperform the standard OAA MCSVMs, showing an average accuracy of 98.66% and 95.01% for bearings under rotational speeds of 50 RPM and 80 RPM, respectively

Reliable fault diagnosis for incipient low-speed bearings using fault feature analysis based on a binary bat algorithm

In this paper, we propose a highly reliable fault diagnosis scheme for incipient low-speed rolling element bearing failures. The scheme consists of fault feature calculation, discriminative fault feature analysis, and fault classification. The proposed approach first computes wavelet-based fault features, including the respective relative wavelet packet node energy and entropy, by applying a wavelet packet transform to an incoming acoustic emission signal. The most discriminative fault features are then filtered from the originally produced feature vector by using discriminative fault feature analysis based on a binary bat algorithm (BBA). Finally, the proposed approach employs one-against-all multiclass support vector machines to identify multiple low-speed rolling element bearing defects. This study compares the proposed BBA-based dimensionality reduction scheme with four other dimensionality reduction methodologies in terms of classification performance. Experimental results show that the proposed methodology is superior to other dimensionality reduction approaches, yielding an average classification accuracy of 94.9%, 95.8%, and 98.4% under bearing rotational speeds at 20 revolutions-per-minute (RPM), 80 RPM, and 140 RPM, respectively