Differentiation of Speech Delay and Global Developmental Delay in Children Using DTI Tractography-Based Connectome

BACKGROUND AND PURPOSE: Pure speech delay is a common developmental disorder which, according to some estimates, affects 5%-8% of the population. Speech delay may not only be an isolated condition but also can be part of a broader condition such as global developmental delay. The present study investigated whether diffusion tensor imaging tractography-based connectome can differentiate global developmental delay from speech delay in young children. MATERIALS AND METHODS: Twelve children with pure speech delay (39.1 +/- 20.9 months of age, 9 boys), 14 children with global developmental delay (39.3 +/- 18.2 months of age, 12 boys), and 10 children with typical development (38.5 +/- 20.5 months of age, 7 boys) underwent 3T DTI. For each subject, whole-brain connectome analysis was performed by using 116 cortical ROls. The following network metrics were measured at individual regions: strength (number of the shortest paths), efficiency (measures of global and local integration), cluster coefficient (a measure of local aggregation), and betweeness (a measure of centrality). RESULTS: Compared with typical development, global and local efficiency were significantly reduced in both global developmental delay and speech delay (P < .0001). The nodal strength of the cognitive network is reduced in global developmental delay, whereas the nodal strength of the language network is reduced in speech delay. This finding resulted in a high accuracy of >83% 4% to discriminate global developmental delay from speech delay. CONCLUSIONS: The network abnormalities identified in the present study may underlie the neurocognitive and behavioral consequences commonly identified in children with global developmental-delay and speech delay. Further validation studies in larger samples are required.