Is somatosensory temporal discrimination threshold a biomarker of disease progression in multiple sclerosis?

Temporal processing of tactile information can be neurophysiologically investigated by measuring the somatosensory temporal discrimination threshold (STDT), i.e. the shortest interval needed to recognize two consecutive stimuli as distinct in time. STDT depends on cortico-subcortical grey matter structures interplay, with a pivotal role of the primary somatosensory cortex and thalamus (Conte et al., 2020). We previously observed that STDT was impaired in multiple sclerosis (MS) patients (Rocchi et al., 2016) and that this abnormality was present even in patients with low disability and normal somatosensory evoked potentials latencies (Conte et al., 2020). In addition, we found that STDT correlated with clinical disability in MS patients and with thalamic volume as tested by magnetic resonance imaging (Conte et al., 2020). However, it is unknown whether STDT abnormalities in MS reflect a static phenomenon or parallel disease progression. The aim of the presen