Identification of modified dynamic gait index cutoff scores for assessing fall risk in people with Parkinson disease, stroke and multiple sclerosis

Background: Balance and gait impairments increase fall rate and injury in people with neurological disorders(PwND). The modified Dynamic Gait Index(mDGI) is a scale assessing dynamic balance during walking, however its ability in identifying Fallers and Recurrent Fallers has not been studied. Research Question: To evaluate mDGI's ability in identifying retrospective Fallers and Recurrent Fallers establishing cut-off scores for its use in clinical practice. Method: In this cross-sectional study, the number of retrospective falls and mDGI scores were collected. PwND were categorised as Non-Fallers or Fallers (falls≥1) and as Recurrent Fallers(falls≥2) or Non-Recurrent/Non-Fallers(falls<2) according to their number of retrospective falls over two months. Two generalised linear logistic models were developed using a machine learning method to detect Fallers (Model 1) and Recurrent Fallers (Model 2) based on mDGI scores. ROC curves were used to identify mDGI cut-off scores to distinguish between different fall categories. Results: 58 PwND (mean ± standard deviation age: 63.4 ± 12 years) including 28 people with Multiple Sclerosis, 15 people with Parkinson's disease and 15 people with Stroke were analysed. The mDGI score(median (IQR)) for Non-Fallers, Fallers, Recurrent Fallers and Non-Recurrent/Non-Fallers was respectively 50(22), 37(22), 26.5(20.25) and 46.5(20.5)points. The cut-off to identify Fallers from Non-Fallers was 49 points(sensitivity:100 %, specificity:50 %, post-test probability with mDGI ≤ cut-off: 53.2 %, post-test probability with mDGI > cut-off: 0%, AUC:0.68), while 29 points(sensitivity:60 %, specificity:79 %, post-test probability with mDGI ≤ cut-off:52.1 %, post-test probability with mDGI > cut-off:16.1 %, AUC:0.70) was the best cut-off to identify Recurrent Fallers. Significance: People with mDGI score>49 points have low or minimal fall risk, while people with mDGI score≤49 points should be further investigated with other scales before starting a balance-focused rehabilitation intervention. People scoring ≤29 points on the mDGI scale may need a fall prevention intervention, regardless of the results of other balance clinical measures.