Left-right differences in the proximal femur's strength of post-menopausal women: a multicentric finite element study.

UNLABELLED: The strength of both femurs was estimated in 198 post-menopausal women through subject-specific finite element models. Important random differences between contralateral femurs were found in a significant number of subjects, pointing to the usefulness of further studies to understand if strength-based classification of patients at risk of fracture can be affected by laterality issues. INTRODUCTION: Significant, although small, differences exist in mineral density and anatomy of contralateral proximal femurs. These differences, and their combined effect, may result in a side difference in femurs' strength. However, this has never been tested on a large sample of a homogenous population. METHODS: The strength of both femurs was estimated in 198 post-menopausal women through CT-derived finite element models, built using a validated procedure, in sideways fall conditions. The impact of the resulting asymmetry on the classification of subjects at risk of fracture was analysed. RESULTS: The small difference observed between sides (the right femur on average 4 % stronger than the left) was statistically significant but mechanically negligible. In contrast, higher random differences (absolute difference between sides with respect to mean value) were found: on average close to 15 % (compared to 9.2 % for areal bone mineral density (aBMD) alone), with high scatter among the subjects. When using a threshold-based classification, the right and left femurs were discordant up to over 20 % of cases (K always lower than 0.60) but the left femur was concordant (mean K = 0.84) with the minimum strength between right and left. CONCLUSION: Considering both femurs may be important when trying to classify subjects at risk of failure with strength estimates. Future studies including fracture assessment would be necessary to quantify the real impact.

Mechanography performance tests and their association with sarcopenia, falls and impairment in the activities of daily living - a pilot cross-sectional study in 293 older adults.

OBJECTIVES: Muscle mass and muscle power considerably decline with aging. The aim of the present study was to determine the association between muscular function using mechanography and sarcopenia, falls and impairment in the activities of daily living (ADL) in a sample of 293 community-dwelling women and men aged 60-85 years in Berlin, Germany. METHODS: Muscle function was determined by muscle power per body mass in vertical countermovement jumps (2LJPrel) and the chair rising test (CRTPrel) on a force plate. Sarcopenia status was assessed by estimating appendicular muscle mass with dual-X-ray absorptiometry. Self-reported ADL impairment and falls in the last 12 months were determined. RESULTS: ADL impairment was significantly correlated with all performance tests but not with muscle mass. The 2LJPrel (OR 0.88, 95%-CI 0.79-0.98), the Esslinger Fitness Index (EFI) (OR 0.97, 95%-CI 0.94-1.00) and the maximal velocity of the CRT (OR 0.70, 95%-CI 0.53-0.93) remained significant correlates for sarcopenia independent of age in men but not in women. The EFI could differentiate female individuals who had past fall events (OR 0.96, 95%-CI 0.93-0.98). CONCLUSION: The results of the present study highlight the importance of assessing muscle power in older individuals as a relevant correlate for functional decline.

Identification of functional parameters for the classification of older female fallers and prediction of 'first-time' fallers.

Falls remain a challenge for ageing societies. Strong evidence indicates that a previous fall is the strongest single screening indicator for a subsequent fall and the need for assessing fall risk without accounting for fall history is therefore imperative. Testing in three functional domains (using a total 92 measures) were completed in 84 older women (60-85 years of age), including muscular control, standing balance, and mean and variability of gait. Participants were retrospectively classified as fallers (n = 38) or non-fallers (n = 42) and additionally in a prospective manner to identify first-time fallers (FTFs) (n = 6) within a 12-month follow-up period. Principal component analysis revealed that seven components derived from the 92 functional measures are sufficient to depict the spectrum of functional performance. Inclusion of only three components, related to mean and temporal variability of walking, allowed classification of fallers and non-fallers with a sensitivity and specificity of 74% and 76%, respectively. Furthermore, the results indicate that FTFs show a tendency towards the performance of fallers, even before their first fall occurs. This study suggests that temporal variability and mean spatial parameters of gait are the only functional components among the 92 measures tested that differentiate fallers from non-fallers, and could therefore show efficacy in clinical screening programmes for assessing risk of first-time falling.

Cross-sectional assessment of neuromuscular function using mechanography in women and men aged 20-85 years.

OBJECTIVES: The aim of this cross-sectional study was to examine the influence of age and sex on neuromuscular function of the lower limbs using mechanography. 704 adults aged 20-85 years from Germany participated in this study. METHODS: Ground reaction force and power were assessed with countermovement jumps and the chair rising test on a ground reactions force plate. RESULTS: While ground reaction force per unit body mass declined by about 20% from the third to the ninth decade, the decline of power per unit body mass was much greater, varying between 40-50%. Men and women are affected equally by the decline. Age and sex explained the variability of the power parameters to a much greater extent (R(2)=0.54 to R(2)=0.70) than the force parameters (R(2)=0.18 to R(2)=0.36). CONCLUSIONS: Our reference values can help to identify those who might be affected by the development of sarcopenia. Preventive exercise programs should focus on preserving muscle power in addition to the training of muscle force.

Assumptions in borderline personality disorder: specificity, stability and relationship with etiological factors.

The specificity and stability of a set of assumptions hypothesized to be characteristic of Borderline Personality Disorder (BPD) was investigated. BPD patients (n = 16) were compared to cluster-C personality disorder patients (n = 12) and to normal controls (n = 15). All subjects were female and diagnosed with SCID-I and -II. Subjects rated a short version of the Personality Disorder Beliefs Questionnaire (PDBQ), with six sets of 20 assumptions each, hypothesized to be characteristic of avoidant, dependent, obsessive-compulsive, paranoid, histrionic and borderline personality disorder. The BPD assumptions (Cronbach alpha = 0.95) proved to be the most specific to BPD patients. Subjects rated the shortened PDBQ again after viewing an emotional video fragment one week later. Despite increased negative emotions, the PDBQ ratings remained relatively stable. Confirming the cognitive hypothesis, regression analyses indicated that the BPD assumptions mediate the relationship between self-reported etiological factors from childhood (sexual abuse and emotional/physical abuse) and BPD pathology assessed with the SCID-II. It is suggested that a set of assumptions is characteristic of BPD, and is relatively stable despite the instability of the behaviour of people diagnosed as having BPD.