The Universities of Tübingenü and Kiel Investigate how Fear of Falling Influences Parkinson’s Patients’ Turning Strategies

Decreases in skeletal muscle mass and strength are a natural part of the aging process. Functional decline over time makes static and dynamic balance a more challenging task and makes elderly people more prone to falls. Falls are of grave concern to an aging population as they can result in a hip fracture that reduces mobility and requires a long period of recovery. Combine aging with a chronic, neurodegenerative disease and the likelihood of falling increases substantially. Up to 68% of patients with Parkinson’s disease (PD) fall at least once a year, many of them suffering injuries like hip fractures that greatly reduce their quality of life [Voss et al., 2012].

What is Parkinson’s Disease?

Parkinson’s disease is a chronic, degenerative neurological disorder that tends to affect individuals over 60, although some people are diagnosed at 40 or younger. Parkinson’s disease is a disorder of the central nervous system resulting in a loss of function of the substantia nigra, which is the part of the brain responsible for producing dopamine. In order for neurons to fire normally, they rely on dopamine for transmitting signals related to movement coordination. A loss of dopamine results in a loss of normal motor control [MJF Foundation for Parkinson’s Research].

Slow for the Turn

Studies have shown that Parkinson’s patients tend to turn slower, with more steps, and at a reduced turning angle than their healthy counterparts [El-Gohary et al., 2013]. A normal adult would turn by first rotating their head, then the thorax, and lastly the pelvis. Parkinson’s patients exhibit axial rigidity that causes their head, thorax, and pelvis to rotate simultaneously thereby increasing their instability while turning. Recent studies have indicated that fear of falling and a positive history of falls contribute to future falls in Parkinson’s patients [Bryant et al., 2014].

Fear of Falling

A team of researchers at the Hertie-Institute for Clinical Brain Research in Tübingenü and the Center of Neurology in Kiel, Germany wanted to evaluate the impact of a positive fall history and the presence of fear of falling on the turning strategy of Parkinson’s patients. Linda Haertner and her colleagues assessed 55 Parkinson’s disease patients using a standardized assessment in the lab and tracked natural turns in the home. Each participant wore an Opal wearable sensor positioned at the top of the sacrum to track movement data while performing two instrumented Timed Up and Go (iTUG) trials in the laboratory. The iTUG trial began with the subject seated, standing to walk a distance of 7 meters, turning 180o, walking back to the chair, turning 180o, and sitting down again. Data was collected using the Mobility Lab software and the results for turn duration, turn angle, and angular velocities throughout the turn are based on [Pham et al., 2017]. In the home, approximately 10,000 turns were identified per person over a 12-day period of continuous monitoring using another inertial measurement unit.

The Study Results

The researchers at the Universities of Tübingenü and Kiel found that

Fear of falling, but not a positive history of falls, induces changes of turning parameters in Parkinson’s patients, regardless of history of previous falls and whether the turns were evaluated in the lab or at home.

Interestingly, some turn parameters differed substantially, depending on whether the patients were assessed in the clinic or at home. In the clinic, among the participants with a positive fall history, those with a fear of falling showed longer turn durations and lower middle angular velocities of turns compared with those who do not fear falling. In the home, these patients showed shorter turn durations and lower angular velocities. As fear of falling contributes substantially to unstable turning, evaluating this fear in newly diagnosed Parkinson’s patients (in both the clinic and home) could provide an opportunity for early and specific intervention and fall prevention [Haertner et al., 2018].

Aiding Fall-Risk Assessments

APDM Wearable Technologies offers sensor-based solutions for quantifying human movement. Independently validated and trusted by thousands of researchers worldwide, APDM’s digital health solutions are used to analyze full-body kinematics, gait, and balance. Applications range from neurological assessments, rehabilitation research, clinical trials, fall-risk, continuous monitoring, and more. To learn more about incorporating APDM’s technology into your upcoming research study and to view recent publications please visit


  1. Voss, T. S., Elm, J. J., Wielinski, C. L., Aminoff, M. J., Bandyopadhyay, D., Chou, K. L., et al. (2012). Fall frequency and risk assessment in early Parkinson’s disease. Parkinsonism Relat. Disord. 18, 837–841. doi: 10.1016/j.parkreldis.2012.04.004
  3. El-Gohary, M., Pearson, S., McNames, J., Mancini, M., Horak, F., Mellone, S., et al. (2013). Continuous monitoring of turning in patients with movement disability. Sensors 14, 356–369. doi: 10.3390/s140100356
  4. Bryant, M. S., Rintala, D. H., Hou, J.-G., and Protas, E. J. (2014). Influence of fear of falling on gait and balance in Parkinson’s disease. Disabil. Rehabil. 36, 744–748. doi: 10.3109/09638288.2013.814722
  5. Pham MH., Elshehabi M., Haertner L., Del Din S., Srulijes K., Heger T., et al. (2017). Validation of a Step Detection Algorithm during Straight Walking and Turning in Patients with Parkinson’s Disease and Older Adults Using an Inertial Measurement Unit at the Lower Back. Front. Neurol. 8:457. doi: 10.3389/fneur.2017.00457
  6. Haertner L, Elshehabi M, Zaunbrecher L, Pham MH, Maetzler C, van Uem JMT, et al. (2018) Effect of Fear of Falling on Turning Performance in Parkinson’s Disease in the Lab and at Home. Front. Aging Neurosci. 10:78. doi: 10.3389/fnagi.2018.00078
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