Categorisation of falls in an incident cohort of Parkinson's disease and effect of ambulatory activity on falls

Abstract

Objective: 1) Prospectively quantify and describe falls over a 12 month period in an incident cohort of Parkinson's disease (PD) with respect to frequency and event related activity which triggered the fall; and 2) examine the relationship between falls and baseline ambulatory activity. Background: Few studies have categorised falls in early PD and little is known about falls incidence and evolution. Furthermore while fall incidence and frequency are reported to be 'U' shaped with respect to disease severity, this is also likely to be influenced by time spent engaged in ambulatory activities which mediate potential risk. Methods: Participants were recruited from an ongoing longitudinal study (ICICLE-PD). Daily activity was measured via accelerometry (ActivPalTM) for 7 days. Fall events were collected over 12 months using a monthly diary and follow-up phone calls. Falls were categorised by fall frequency (non-faller, single fall, recurrent falls) and with respect to the activity which triggered the event (1) engaged in high risk activity; (2) walking; and (3) during postural transitions). ANCOVA was used to compare non-fallers, single and recurrent fallers at 12 months and Students t test to compare fallers according to event related activity (high risk+walking combined vs. postural transitions). Results: At baseline 27 (22.6%) of the full cohort (N=122) had fallen. Twelve month data for 111 participants (median age 68.7 years) were analysed. There were no significant differences in baseline ambulatory activity outcomes between non-fallers (63.1%), single fallers (15.3%) and recurrent fallers (21.6%) although recurrent fallers had significantly higher baseline Hoehn & Yahr and UPDRS II scores (P 50.01 and P=0.01 respectively). Participants who fell during postural transitions were significantly older than other fallers: 73.0 years vs. 65.0 years (P 50.02), and spent less time walking 3.6% vs. 5.6% (P 50.01). Conclusions: Falls are more common than recognised in newly diagnosed PD. Age and reduced daily activity are potential markers for patients at risk of the 'classic PD' postural-transition fall. Classification methods that take event related activity into account may be more useful to identify significant correlates and understand the heterogeneity of this complex problem.