The Neural Activity Changes Of The Visual Cortex In The Cervical Spondylotic Myelopathy Patients-a Resting-state FMRI Study

Purpose We sought to investigate visual cortex neural activity alterations in cervical spondylotic myelopathy(CSM)patients using resting-state f MRI(rs-f MRI)and to explore the relationships of these alterations with visual disorder.Methods Subject: Twenty-seven CSM patients and 11 healthy controls were recruited as the study and control groups.A total of 27 right-handed CSM patients(15 male/12 female;age = 57.9±9.1 years;education years = 10.8 ± 2.7 years)were recruited continuously from May 2016 to December 2016 at Tianjin Medical University General Hospital(Tianjin,China).Eleven healthy subjects of similar age,gender,and education years(6 male/5 female;age = 54.8±8.4 years,education years = 11.6 ± 2.5 years)were also recruited.This study was approved by the local Institutional Review Board of Tianjin Medical University General Hospital(Tianjin,China).Informed written consent was obtained from all participants before each procedure.Data acquisition: All MR data were acquired using a 3.0-T magnetic resonance scanner(Discovery MR750,General Electric).Earplugs were placed inside the subjects’ ears to minimize noise.The subjects were instructed to keep their head still during the scanning,and a sponge pad was used to fix the patient’s head to minimize unconscious activity.The subjects were instructed to keep their eyes closed but remain awake and without specific or strong ideological activities.The functional images and structural images were both collected.The best-corrected visual acuity of the study group were measured with the Early Treatment Diabetic Retinopathy Study(ETDRS)chart before and 6 months after surgery.Data processing: MR data were preprocessed with the Data Processing Assistant for rsf MRI toolbox(DPARSF;http://www.restfmri.net/forum/DPARSF).The amplitude of low-frequency fluctuations(ALFF)and regional homogeneity(Re Ho)values were calculated to represent neural activity,and the outcomes were compared between groups with the SPM12(Statistical Parametric Mapping;http://www.fil.ion.ucl.ac.uk/spm/software/spm12/).The preoperative best-corrected visual acuity and the postoperative best-corrected visual acuity of study groups were measured.Correlation analyses of the ALFF/Re Ho values with the preoperative and postoperative best-corrected visual acuity were performed.Correlations of the bilateral best-corrected visual acuity with the ipsilateral and contralateral visual cortex neural activities were performed.Results The study group exhibited significantly decreased ALFF values in the occipital lobe(bilateral precuneus and left calcarine)and an increase in the cerebellar posterior lobe(P < 0.05).Moreover,significantly decreased Re Ho values were observed in the occipital lobe(bilateral cuneus,bilateral calcarine,and bilateral precuneus),and an increase was found in the bilateral cerebellar posterior lobe(P < 0.05).Postoperatively,the best-corrected visual acuities were ameliorated in 22 oculi dexter(ODs)and 20 oculi sinister(OSs)in the study group.Positive correlations between neural activity in the visual cortex and the preoperative and postoperative best-corrected visual acuities were detected in the study group.The bilateral best-corrected visual acuities were positively correlated with either the ipsilateral or contralateral visual cortex neural activity.Conclusion Both ALFF/Re Ho value changes and positive correlations of these changes with bestcorrected visual acuities were demonstrated in CSM.This study provided new insight into the alterations of neural activity in CSM patients and further confirmed the symptom of blurred vision in CSM.