Relationship between tic symptom severity and amplitude of low frequency fluctuation of resting-state functional magnetic resonance imaging of Tourette syndrome

Abstract

To examine the relationship between tic symptom severity and amplitude of low frequency fluctuation (ALFF) brain functioning of the first-episode Tourette syndrome through resting-state functional magnetic resonance imaging (fMRI). Sixteen subjects were all recruited from the outpatient department of pediatrics, Beijing Anding Hospital, Capital Medical University and were all first-episode Tourette syndrome patients [male: 13, female: 3; age: 6-16 years; mean age: (11.00 ± 2.92) years]; mean education time: (5.06 ± 2.86) years; course: 14-104 months; mean (48.44 ± 25.00) months; scores of YGTSS at baseline: tic severity score: 37.88 ± 5.39; global damage score: 25.63 ± 12.63. All the subjects experienced resting-state fMRI scans and ALFF were calculated in three frequency ranges: 0.01-0.1 Hz, 0.01-0.027 Hz and 0.027-0.073 Hz. First-episode Tourette syndrome patients and 16 gender, age, and education-matched normal controls experienced resting-state fMRI scans. Correlation analysis was performed in between the amplitude of low frequency fluctuation (ALFF) and the severity of tic symptom. P < 0.05 and k value ≥ 10 were considered to be of significance. In tic symptom patients, tic severity (total tic scores of YGTSS) was positively correlated with the ALFF values in the orbital part of left superior frontal gyrus (0.01-0.1 Hz:r = 0.83,0.027-0.073 Hz:r = 0.91, P < 0.05, respectively), right middle frontal gyrus (0.01-0.027 Hz:r = 0.85,0.027-0.073 Hz:r = 0.57, P < 0.05, respectively ) and orbital part of left middle frontal gyrus (0.01-0.027 Hz:r = 0.64, P < 0.05). Tic severity was negatively correlated with the ALFF values in the right calcarine fissure and surrounding cortex (0.01-0.1 Hz:r = -0.65,0.01-0.027 Hz:r = -0.69, P < 0.05, respectively ) and the left calcarine fissure and surrounding cortex (0.027-0.073 Hz:r = -0.81, P < 0.05). Tic symptom severity of the first-episode Tourette syndrome is associated with abnormal brain activity patterns of specific brain areas.