Increased thalamic intrinsic oscillation amplitude in relapsing-remitting multiple sclerosis associated with the slowed cognitive processing

Abstract

Objective: To investigate the relationship between the amplitude of thalamic intrinsic neuronal activity, structural imaging indices, and the clinical neurological scales in relapsing-remitting multiple sclerosis (RRMS).

Methods: Twenty-three patients with RRMS and 23 healthy controls were examined by resting-state fMRI (rs-fMRI) scan. Thalamic intrinsic oscillation amplitude was calculated by amplitude of low frequency fluctuation (ALFF) of rs-fMRI, as well as its correlations with clinical and structural imaging indices.

Results: Compared with the healthy controls, RRMS patients showed significantly increased ALFF values in bilateral thalami (P<.05, corrected). In the patient group, positive correlation was found between bilateral ALFF values and paced auditory serial addition test (left: P=.033; right: P=.016). Significant correlation was detected between the ALFF values and fractional anisotropy (FA) values in the left thalamus (r=0.550, P=.007); only tendency increased correlation was detected between the ALFF values and FA values in the right thalamus (P=.114). No correlation was observed between bilateral thalamic ALFF values and disease duration, expanded disability status scale score, brain parenchymal fraction, or total white matter lesion loads (P>.05).

Conclusion: The increased thalamic intrinsic oscillation amplitude as an ineffective reorganization was responded to microstructural damage in the RRMS patients, as well as it was associated with the slowed cognitive processing in relatively minimally disabled stage.

Keywords: Amplitude of low frequency fluctuation; Cognitive dysfunction; Relapsing–Remitting multiple sclerosis; Resting-state, functional MRI; Thalami.