Towards better fall prevention –:Examining the interplay between factors that influence gait in older patients.

Falling is a serious problem among older patients: it is the combination of a high fall incidence together with a high susceptibility to injuries that makes a relatively mild fall potentially dangerous to these old persons. Falling is a multifactorial problem, but postural instability during daily activities, such as walking, is suggested to be the most consistent predictor of falls. Age-related neurophysiological changes and a high prevalence of clinical diseases result in a slower and less coordinated gait in older patients. These changes in the gait pattern can be quantified by a wide variety of gait parameters, each characterizing different aspects of the gait pattern. Several studies among relatively young and healthy older adults have shown that gait characteristics, such as gait speed, stride-to-stride variability, gait asymmetry, harmonic ratios, and sample entropy, can differentiate fallers from non-fallers. However, these results of these studies cannot be extrapolated to older patients, since in these old patients there are, besides the normal age-related neurophysiological changes, additional comorbid factors present that might affect the walking pattern, and consequently increase fall risk. Therefore, in the present thesis, it was aimed to examine the association between several phenomena that occur common in geriatric patients, including osteoporosis-related factors (e.g., vertebral fractures, increased thoracic kyphosis, and a flexed posture; part I of this thesis), medication-use (e.g., fall-risk-increasing drugs, such as antidepressants, benzodiazepines and antiepileptics; part II), and frailty-related factors (e.g., muscle strength and weight loss; part III) with postural control during walking in older patients visiting a geriatric outpatient clinic. Based on the studies described in the first part of this thesis, it was concluded that patients with a flexed posture, an increased thoracic kyphosis, and/or prevalent vertebral fractures have an impaired postural control. This might be the underlying mechanism for the increased fall incidence that was found in patients with an increased thoracic kyphosis. The second part of this thesis described that postural control was impaired in healthy young and older adults when they used psychotropic drugs. These effects were not so clearly manifested in older patients, since frailty-related parameters in this population were stronger associated with impaired gait performance than the use of psychotropic medications. Since impairments in gait and balance are the main risk factors for falls, this emphasizes the need for a multifactorial approach in fall risk assessment, as described in the third part of this thesis, including gait analysis, medication review, and screening for frailty- and osteoporosis-related factors, in order to protect patients at risk for falling in an early stage and offer them an individualized intervention tailed to the identified fall risk factors