Simple test predicts Parkinson’s risk nine years before diagnosis

A simple walking test that times how quickly people turn could flag Parkinson’s nearly nine years before diagnosis.

The finding could help spot patients in the prodromal phase – the earliest stage when brain damage starts but symptoms are subtle.

This window can last years before tremor and movement problems prompt diagnosis.

The researchers wrote: “Turning is a complex part of walking. It requires constant coordination, and modification of the locomotor trajectory while moving.

“Difficulties turning are common and highly relevant to daily life in Parkinson’s.

“Therefore, it seems intuitive that turning deficits could be observed, emphasising the need to investigate the predictive potential of turning measures in this phase.”

German neurologists analysed movement patterns of 924 people aged over 50 in the Tübingen Evaluation of Risk Factors for Early Detection of Neurodegeneration (TREND) study.

Participants repeated walking tests five times across 10 years, moving along a 20-metre hallway for one minute at their preferred pace while wearing a tracker on their lower back.

Slower turning at baseline was linked to higher risk of Parkinson’s diagnosis, with differences from healthy controls emerging almost nine years before diagnosis.

By the study’s end, 23 participants had been diagnosed, around five years after initial tests.

Using machine learning that factored in age, sex and maximum turning speed, the team identified 60 per cent of patients in early-stage Parkinson’s.

Those later diagnosed began turning more slowly at wider angles up to 8.8 years before official diagnosis.

This pattern may reflect a general slowdown or reduced balance and postural stability (control of upright stance), both common in Parkinson’s, the researchers said.

“A decline in postural stability may subconsciously incentivise patients to turn slower and adopt a safer route, using a larger arc.”

“This would mean that Parkinson’s patients—who are already in the prediagnostic phase—develop strategies for safer and more stable turning.”

Men were four times more likely than women to develop the disease, and each additional year of age raised risk by 15 per cent.

“Our results suggest that turning measures may aid in predicting the clinical Parkinson’s diagnosis and enhance a panel of prediagnostic markers for identifying high-risk individuals,” the researchers concluded.

“Using a single wearable inertial measurement unit and validated algorithms, the approach used in this study, is practical for large-scale screening for Parkinson’s.” (An inertial measurement unit is a small motion sensor.)

The authors noted limits, including a relatively small sample and assessment of only seven turning measures.

They called for larger studies to test more turning features alongside gait and balance metrics.

There is no definitive test for Parkinson’s.

Diagnosis typically relies on later-stage signs such as tremor after excluding other conditions.

Parkinson’s charities estimate more than one in four patients are initially misdiagnosed.