Altered brain activity in patients with strabismus and amblyopia detected by analysis of regional homogeneity: A resting‑state functional magnetic resonance imaging study

Abstract

Previous studies have demonstrated that strabismus or amblyopia can result in marked brain function and anatomical alterations. However, differences in spontaneous brain activity in strabismus and amblyopia (SA) patients as compared with control individuals remain unclear. The present study aimed to analyze the potential brain activity changes in SA patients and their association with behavioral performance. In total, 16 patients with SA (10 women and 6 men) and 16 healthy controls (HCs; 6 men and 10 women) with matched age and sex were recruited. All subjects were examined with resting‑state functional magnetic resonance imaging (rs‑fMRI), and changes in the spontaneous brain activity of SA patients were evaluated by the regional homogeneity (ReHo) method. The diagnostic ability of the ReHo method was assessed using receiver operating characteristic (ROC) curve analysis. In addition, the association between the mean ReHo value in different brain regions and the behavioral performance was explored by correlation analysis. It was observed that the ReHo value was significantly increased in SA patients compared with HCs in the following brain regions: left lingual gyrus, right middle occipital gyrus/precuneus, bilateral anterior cingulate, left middle occipital gyrus and bilateral precentral gyrus. By contrast, the ReHo value of the left inferior frontal gyrus was significantly lower than that in HCs. ROC curve analysis indicated that the ReHo method has certain credibility for the diagnosis of SA patients. In addition, no similar changes were detected in other brain regions. These results revealed abnormal spontaneous brain activity in certain parts of the brain in adult patients with SA, which suggests the involvement of the neuropathological or compensatory mechanism in these patients, and may be beneficial for clinical treatment.

Figure 1.

Spontaneous brain activity in patients with strabismus with amblyopia. Red regions (left lingual gyrus, right middle occipital gyrus/precuneus, bilateral anterior cingulate, left middle occipital gyrus and bilateral precentral gyrus) indicate higher ReHo values, while blue regions (left inferior frontal gyrus) represent lower ReHo values (P<0.05; AlphaSim-corrected; cluster size, >40). ReHo, regional homogeneity; R, right; L, left.

Figure 2.

Mean ReHo values between the SA and HC groups in different areas of the brain. *P<0.05 vs. HC. ReHo, regional homogeneity; SA, strabismus and amblyopia; HC, healthy control; LLG, left lingual gyrus; RMOG/RP, right middle occipital gyrus/precuneus; BAC, bilateral anterior cingulate; LMOG, left middle occipital gyrus; BPG, bilateral precentral gyrus; LIFG, left inferior frontal gyrus.

Figure 3.

ROC curve analysis of the ReHo values for altered brain regions in the SA group. (A) The area under the ROC curve was 0.934 for LLG (P<0.001; 95% CI, 0.847–1.000), 0.965 for RMOG/RP (P<0.001; 95% CI, 0.911–1.000), 0.902 for BAC (P<0.001; 95% CI, 0.777–1.000), 0.938 for LMOG (P<0.001; 95% CI, 0.860–1.000) and 0.922 for BPG (P<0.001; 95% CI, 0.830–1.000). (B) Area under the ROC curve for LIFG was 0.938 (P<0.001; 95% CI: 0.859–1.000). ROC, receiver operating characteristic; ReHo, regional homogeneity; SA, strabismus and amblyopia; LLG, left lingual gyrus; RMOG, right middle occipital gyrus; RP, right precuneus; BAC, bilateral anterior cingulate; LMOG, left middle occipital gyrus; BPG, bilateral precentral gyrus; LIFG, left inferior temporal gyrus.

Figure 4.

ReHo results of brain activity in the SA group. Compared with the healthy controls, the ReHo values of regions 1–5 in SA patients were increased to various extents, while the value of region 6 was decreased. Region 1 refers the left lingual gyrus (BA 19; t=3.6987), region 2 to the right middle occipital gyrus/right precuneus (BA19; t=4.7141), region 3 to the bilateral anterior cingulate (t=3.8637), region 4 to the left middle occipital gyrus (BA 19; t=4.5112), region 5 to the bilateral precentral gyrus (BA 6; t=5.5492) and region 6 to left inferior frontal gyrus (BA9; t=−4.0693). The size of the spots denotes the degree of quantitative change. ReHo, regional homogeneity; SA, strabismus and amblyopia; BA, Brodmann area.