Cortical motor reorganization after a single clinical attack of multiple sclerosis

Abstract

In order to evaluate whether cortical motor reorganization occurs in the earliest phase of multiple sclerosis, we studied patients after a first clinical attack of hemiparesis. From a consecutive series of 70 patients enrolled in a study of patients with clinically isolated syndrome and serial MRI findings indicative of multiple sclerosis, we retrospectively selected 10 patients with hemiparesis as the onset symptom and no further clinical episode [mean age 32 +/- 9 years, disease duration 24 +/- 14 months, median Expanded Disability Status Score (EDSS) 1.25]. Ten age-matched, healthy subjects served as controls. Each subject was submitted to two functional MRI trials (one per hand) using a 1.5 T magnet during a sequential finger-to-thumb opposition task. Image analysis was performed using SPM99 software. Movements of both the 'affected' and the 'unaffected' hand activated significantly larger areas in patients than in controls in both the contralateral and ipsilateral cortical motor areas. Patients activated a greater number of foci than controls during both the right-hand and the left-hand movement. Most of these foci were located in cortical areas which were less or not at all activated in controls, such as the lateral premotor cortex [Brodmann area (BA) 6], the insula and the inferior parietal lobule (BA 40). Between-group analysis of patients versus controls showed significant (P < 0.001) foci in these areas, principally located in the ipsilateral hemisphere during right-hand movement and in both the cerebral hemispheres during left-hand movement. Time since clinical onset showed a significant positive correlation with the extent of activation in the ipsilateral motor areas (P = 0.006) during the right-hand movement and with the extent of activation in both the ipsilateral (P = 0.02) and contralateral (P = 0.006) motor areas during the left-hand movement. The T(1) lesion load along the motor pathway showed a significant positive correlation (P = 0.007) with the extent of activation in the contralateral motor areas during right-hand movement. Our study shows functional adaptive changes that involve both the symptomatic and asymptomatic hemisphere during a simple motor task in patients who had suffered a single clinical attack of hemiparesis. The extent of these changes increased with the time elapsed since disease onset and the severity of brain damage.

Principal components of functional connectivity: A new approach to study dynamic brain connectivity during rest

“…However, we also confirmed the bilateral parahippocampal gyri, right amygdala, left thalamus and left midtemporal pole as more strongly connected in RRMS patients (Richiardi et al, 2012). Such selective increased FC has been reported by several other studies as well (Bonavita et al, 2011;Dogonowski et al, 2013;Hawellek et al, 2011;Richiardi et al, 2012;Rocca et al, 2012;Roosendaal et al, 2010) and has been interpreted as a compensatory mechanism (Bonavita et al, 2011;Roosendaal et al, 2010) because activation studies have shown increased activity in regions devoted to the task and the recruitment of additional regions in MS patients (Pantano et al, 2002;Rocca et al, 2005). It is however also possible that these increases originate from a loss of flexibility in functional interactions, rather than as a compensatory mechanism (Hawellek et al, 2011).…”

Long-term effect of early treatment with interferon beta-1b after a first clinical event suggestive of multiple sclerosis: 5-year active treatment extension of the phase 3 BENEFIT trial

“…In the early phase of multiple sclerosis, the capacity for repair and compensation of impaired CNS functions is not exhausted 27,28 and can contribute to recovery of overt neurological defi cits.…”

Compensatory cortical activation observed by fMRI during a cognitive task at the earliest stage of multiple sclerosis

“…Indeed, numerous PET and fMRI studies have provided evidence that cortical plasticity may contribute to functional recovery after stroke, tumor, or brain trauma [Cao et al, 1999;Caramia et al, 1998;Chen et al, 2002;Cramer et al, 1997;Levine et al, 2002]. Adaptive cerebral plasticity of the cortical motor system may also limit the clinical expression of tissue impairment in MS [Filippi et al, 2002a,b;Lee et al, 2000a,b;Pantano et al, 2002;Reddy et al, 2000;Rocca et al, 2002;Staffen et al, 2002;Yousry et al, 1998]. This cortical motor reorganization would be present as soon as the earliest stage of MS, in patients with clinically isolated syndrome suggestive of MS (CISSMS) [Pantano et al, 2002].…”

“…Adaptive cerebral plasticity of the cortical motor system may also limit the clinical expression of tissue impairment in MS [Filippi et al, 2002a,b;Lee et al, 2000a,b;Pantano et al, 2002;Reddy et al, 2000;Rocca et al, 2002;Staffen et al, 2002;Yousry et al, 1998]. This cortical motor reorganization would be present as soon as the earliest stage of MS, in patients with clinically isolated syndrome suggestive of MS (CISSMS) [Pantano et al, 2002]. At that stage, cerebral plasticity may contribute to maintain normal motor performance despite tissue damage [Pantano et al, 2002].…”