Authors' reply

摘要

In their respective letters commenting on our paper on video capture of the circumstances of falls in elderly people residing in long-term care,1 Yingfeng Zheng and Desmond O'Neill highlight that visual impairment and gait disorders are established risk factors for falls and that neither were discussed in our paper.Although it was beyond the scope of our paper to analyse these relations, we agree that the characteristics of falls in our study were probably affected by impairments in vision, gait and balance, and the use of specific drugs.2 Additional review of our dataset indicates that these conditions were common in our study participants. Of the 32 participants with falls captured on video who provided consent for us to access their electronic medical records, 20 had adequate vision and 12 were visually impaired. Eight were classified as having "unsteady gait", and in tests of standing balance, 11 were able to maintain a stable position, five were unsteady, nine needed partial support, and seven were unable to attempt the test. The mean number of drugs per participant was nine (SD 4); 18 were taking antipsychotics, six antianxiety drugs, 17 antidepressants, six hypnotics, eight diuretics, and 19 analgesics. The cause of falls in elderly people depends on complex interactions between physiological, environmental, and situational factors.3 By presenting evidence from video capture of the biomechanical causes of imbalance and activities leading to falls in long-term care, our paper adds one piece to a complex puzzle to better understand the cause and prevention of falls in this population. However, we agree that there is certainly more to be gained, in revealing layers of causality and informing patient-based approaches to fall prevention, from larger cohort studies or case-study approaches that link real-life fall data to comorbidities, drugs, and functional status. Most people who fall present with multiple clinical risk factors, making this a challenging task.4 Furthermore, whereas in some cases the pathway between isolated clinical risk factors and falls might seem clear (eg, glaucoma causing reduced visual field and collisions, or peripheral neuropathy causing foot drop and trips), in other cases, understanding causality is more challenging (eg, for cognitive impairment or drug use). Exciting possibilities lie ahead in combining video evidence with the clinical context to reveal these mechanisms.