Papel de la marcha y equilibrio en sujetos ancianos (70-79 años) y muy ancianos (>80 años)

Abstract

Gait and balance in the elderly are two basic examinations that each day have more impact on the comprehensive geriatric assessment and, therefore, on the care of the elderly. Especially gait speed, considered one of the examinations with the greatest predictive power of adverse events as an independent element. Despite this, there are many knowledge gaps on this subject and a great paucity of studies, particularly on healthy people, which prevents establishing reference parameters. In this sense, we did not find Spanish studies that analyze gait and balance in people over 70 years old, and studies from other countries differ greatly both in their results and in their selection criteria for what they consider to be a healthy sample. We also did not find posturography studies on people over 80 years old, so data from younger populations must be extrapolated. In addition, most studies select a sample considered normal by extrapolating exclusion criteria from young people instead of taking into account other typical of older people criteria, such as frailty and falls. On the other hand, the evaluation of gait and balance, as we have mentioned, can help to detect different aging trajectories and predict adverse events. The main objective of this work is to establish normality criteria in the temporospatial parameters of gait, balance and posture in older people with visually normal gait (defined as the absence of pathological gait diagnosed by an expert evaluator). The secondary objectives are to analyze whether the exclusion and inclusion criteria currently used to select a sample to explore the parameters of normal gait are adequate in the elderly, as well as to analyze possible aging trajectories after two years of follow-up and possible influential factors. To answer these questions, an observational, longitudinal study was designed in a noninstitutionalized population that included an initial assessment and a follow-up after two years. The results show significant differences in all gait temporospatial parameters that prevent extrapolating the data from younger people. Taking into accountthe differences we found among countries in the first part of this thesis (bibliographic review), can be explained through the different morphology of the participants, it would be more appropriate to use Spanish parameters instead of international references. In order to extrapolate these results to different populations, this work has generated a formula for personalized determination of normality values for each subject with visually normal gait and for each variable of the march considered and proposes using a confidence interval with our data and the aforementioned formula, whenever possible. In the case of posturography, with the exception of the symmetries load test and most of the rhythm control and directional control items, there is also evidence of its relationship with age. In the available literature there are no data from studies in people over 79 years old, so we propose reference values. Although they have less statistical power, they are the first to be reported. On the other hand, we have found that, even if our sample had a visually normal gait, there are pathological factors (such as frailty and falls) that can modify the normal parameters and may be present in individuals with visually normal gait. Frail and faller subjects with visually normal gait have a higher risk of presenting alterations in gait parameters that increase their risk of suffering adverse consequences in their evolution and, therefore, should be systematically evaluated in this subgroup of patients. For all these reasons, we conclude that it is not correct to extrapolate neither data nor selection criteria from young people to older people, not even the usually accepted average values. With this work we provide both parameters and formulas that can be used in the Spanish population, especially for gait. The possibility of determining normal values for each individual may have great clinical relevance, given the great heterogeneity of these values in the larger population. Thus, we fill a diagnostic gap in clinical practice. In addition, we propose the use of posturography and Gait Rite as diagnostic screening for frailty and falls. On the one hand, it can help to detect them before already validated screening scales such as the SPPB and gait speed and before gait alterations are visually detected. The classical variables in the different logistic models and in most cases do not allow the construction of models with great explanatory capacity, which supports their multicausality and the difficulty in a systematized approach, both from the diagnostic and therapeutic point of view. Even so, examination by posturography and Gait Rite may serve to detect aging trajectories independently of frailty and falls (factors already proven predictors of trajectories) in participants considered healthy. With this, this work can contribute to reduce the knowledge gaps in the subject and to improve the daily clinical practice of the elderly.