RELATING MUSCLE MRI WITH GAIT PARAMETERS AND EXPLORING THE EFFECT OF ANKLE FOOT ORTHOSES IN PEOPLE WITH HEREDITARY MOTOR NEUROPATHY

A. Alangary^1,2, C.-C. Chou¹, J. Morrow¹, M. Laura¹, A. Rossor¹, M.M. Reilly¹, G. Ramdharry¹

¹UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square Centre for Neuromuscular Diseases, London, United Kingdom, ²King Saud University, Riyadh, Saudi Arabia

Background: Distal Hereditary Motor Neuropathy (DHMN) is an inherited neuromuscular disorder characterised by distal weakness. It is a disabling condition and eventually many patients need aids to walk. Research is needed to understand the muscle impairments that lead to altered gait patterns, and to develop interventions to correct walking gait conservatively. The data presented here focuses on relationships between intramuscular fat fraction, muscle strength, and kinematics of gait. We also explored bilateral carbon fibre ankle foot orthoses (CFAFO) on people with DHMN.

Methods: Eleven DHMN adult participants underwent lower limbs MRI scan, isokinetic and isometric dynamometer, and 3D gait analysis. To explore the effect of CFAFOs, they underwent an additional gait analysis wearing them.

Results: The primary analysis showed:

• MRI T1-weighted cross-sectional scan at the calves' level showed involvement of calves’ muscles mostly at the posterior compartment (plantar flexors).
• The stride length has a moderate to strong correlation with the Soleus Muscle fat infiltration; 0.601(P= 0.1153) and 0.715 (P= 0.0461) for the right and left sides respectively. However, the correlation with other plantar flexor muscles was weak to very weak (<0.5). The correlation of stride length with plantar flexors isometric torque values was higher than the isokinetic.
• The gait significantly improved with using AFO in speed (P=0.0266). Step length (P=0.0032), stride length (P=0.0031), and the stance phase (P=0.0395). However, this improvement was shown on the right side only and this is probably due to the visibility issue of the left side and the lab settings.

Conclusions: We present a DHMN cohort showing greater plantar flexor muscle weakness. This was associated with reduced ankle torque and stride length. Variation existed between cases, however, with differences in ankle strength and MRI findings, indicating that this is not a homogenous group of diseases. The study's preliminary results showed that carbon fibre ankle foot orthoses can compensate for calf weakness and improve the gait of people with DHMN. Results also showed that 3D gait analysis is a valuable tool for research to measure gait spatiotemporal parameters.

Implications: By evaluating the impact of the disease on function, the results will provide guidance for health practitioners and clinical experts on how to improve patient care and improve their outcomes in terms of walking and mobility. The data provides information to conduct a sample size calculation for a larger trial.

Funding acknowledgements: Alangary is funded by SaudiArabian Cultural Bureau in UK. This research was supported by the NIHR UCLH Biomedical Research Centre.

Keywords:
Gait analysis
MRI
DHMN

Topics:
Neurology
Disability & rehabilitation

Did this work require ethics approval? Yes

Institution: NHS

Committee: Research Ethics Committee

Ethics number: 20/LO/0519