Machine learning for exploring neurophysiological functionality in multiple sclerosis based on trigeminal and hand blink reflexes

Abstract

Brainstem dysfunctions are very common in Multiple Sclerosis (MS) and are a critical predictive factor for future disability. Brainstem functionality can be explored with blink reflexes, subcortical responses consisting in a blink following a peripheral stimulation. Some reflexes are already employed in clinical practice, such as Trigeminal Blink Reflex (TBR). Here we propose for the first time in MS the exploration of Hand Blink Reflex (HBR), which size is modulated by the proximity of the stimulated hand to the face, reflecting the extension of the peripersonal space. The aim of this work is to test whether Machine Learning (ML) techniques could be used in combination with neurophysiological measurements such as TBR and HBR to improve their clinical information and potentially favour the early detection of brainstem dysfunctionality. HBR and TBR were recorded from a group of People with MS (PwMS) with Relapsing-Remitting form and from a healthy control group. Two AdaBoost classifiers were trained with TBR and HBR features each, for a binary classification task between PwMS and Controls. Both classifiers were able to identify PwMS with an accuracy comparable and even higher than clinicians. Our results indicate that ML techniques could represent a tool for clinicians for investigating brainstem functionality in MS. Also, HBR could be promising when applied in clinical practice, providing additional information about the integrity of brainstem circuits potentially favouring early diagnosis.

“Surrounded, detached”: the relationship between defensive peripersonal space and personality

“…Defensive peripersonal space (DPPS) has been defined as the part of the PPS where there is increased physiological reactivity to stimuli that are potentially harmful to the body (4,5). The DPPS can be investigated using the Hand Blink Reflex (HBR) task (6)(7)(8) which measures the changes in orbicularis oculi muscles contraction in response to an electrical stimulation of the median nerve when the arm is placed in different positions with respect to the head. In particular, in a static position of the arm, the HBR is modulated by the hand position in space: the response dramatically increases when the stimulated hand is located close to the face, inside the DPPS (8).…”