Purpose: Difficulty turning (DT) is common in Parkinson's disease (PD). We set out to answer the questions: (1) do people who do and do not report DT differ in postural stability, heel strike, the use of support and step count when performing functional turns during everyday tasks, (2) is the structured observation of functional tasks an ecologically valid way of assessing an individual's ability to turn and (3) does a history of DT predict freezing and/or falls.
Method: At home, 75 people (median age 75 years; PD duration 7 years) answered questions about DT, freezing and falls and completed a standard 180 degrees turn test and an everyday task necessitating spontaneous turns, later rated from video by blinded assessors.
Results: Forty-two people reported DT, of whom 86% reported frequent freezing and/or falls. Twenty-six people with DT and 15 without completed the functional task. Greater proportions of the former appeared Unstable (12 vs 1; P = 0.014), lacked Heel Strike (25 vs 9; P = 0.006) and Used Support (7 vs 0; P = 0.035): the former took more Turning Steps (medians 6 vs 4; P = 0.001). The 95% limits of agreement between step counts (functional vs standard turns) ran from -6.3 to 3.6 steps. Of 49 people with a history of freezing and/or falls, 36 (73%) reported frequent DT.
Conclusions: People who report DT turn differently to those who report no problems. Standard turn tests poorly reflect step count during real-life turning, whereas unobtrusive structured observation reveals the turning strategies people use, so can guide rehabilitation. Reported DT is a sensitive indicator of freezing and/or falling, both indicators for physiotherapy.