Falls due to deteriorating balance control are a major cause of disability and death in older people. Sporadic cerebral small vessel disease (cSVD) – as the commonest acquired brain disease – is a potentially preventable cause of this decline. Despite the importance of cSVD, the effects on balance control in those with mild and moderate disease burdens are difficult to detect.

cSVD usually progresses either asymptomatically, or with non-specific symptoms such as dizziness. A lack of balance-specific symptoms may relate to protective (reserve) factors, and compensatory increases in balance-related brain activity. Large studies have found that clinical measures of standing balance (as distinct from other measures of lower limb performance), and common measures of body sway are insensitive to the effects of cSVD on balance control. Better measures are therefore needed to identify those at risk of balance control decline, to enable treatment to be targeted in the earlier stages of cSVD.

Recent studies have shown functional measures of balance-relevant brain activation are sensitive to compensatory changes in brain activation which occur with ageing (and thus potentially in cSVD). Small vessel disease pathology is also known to affect other parts of the nervous system – such as the spinal cord – potentially also relevant to balance, but this has so far not been measured in life.

My research seeks to pilot the use of modern methods to determine if:

- balance-correcting responses and balance-related prefrontal cortical activity are sensitive to the effects of cSVD on balance control;

- state-of-the-art structural MRI methods can detect the sequelae of small vessel disease in the spinal cord.

My work thus seeks to advance our ability to detect the effects of small vessel disease relevant to balance control. Success would enable future work targeting treatments to high-risk individuals to prevent falls.

Perturbation protocol, predicted effects of SVD on balance-related prefrontal cortical activity, and pilot functional near-infrared spectroscopy data. A - Perturbation protocol: (i) the trunk is perturbed forwards or backwards using motorised pulleys; image adapted from St. George et al. (St George, R. J. et al. J. Physiol. 598, 1929–1941 (2020)); (ii) example stimulus. B – Pilot data I collected from a young adult who received 13 backward pulls over 4 minutes of large (orange) or small (blue) amplitude; top – stimulus; bottom – summary convolved prefrontal cortical oxyhaemoglobin (ΔHbO2) response, revealing amplitude-sensitive activity; head image adapted from Al-Yahya et al (36 Al-Yahya, E. et al. Neurorehabil. Neural Repair 30, 591–599 (2016)); C – Models of brain ageing predict higher prefrontal activation responses and a steeper balance demand-response gradient in early cSVD (green box); image adapted from Reuter-Lorenz & Cappell (Reuter-Lorenz, P. A. et al. Curr. Dir. Psychol. Sci. 17, 177–182 (2008)) .

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