Table 2 Summary of callosal malformations in select developmental disabilities that are diagnosed solely by behavior patterns
Condition | Structural variations | Functional impact of callosal variation | |||
|---|---|---|---|---|---|
Total CC | Anterior (rostrum and genu) | Midbody | Posterior (isthmus and splenium) | ||
Developmental language delay | No significant findings | Low FA in genu (Kim et al. 2006) | No significant findings | Slightly smaller splenium (Preis et al. 2000) | Sensory-motor deficits during IHT task in children (Fabbro et al. 2002) |
Dyslexia | No significant findings | No significant findings | No significant findings | Enlarged splenium (Duara et al. 1991; Rumsey et al. 1996; Kilian et al. 2008) | Phonological processing skill correlates with IHT of tactile info in dyslexic adults (Moore et al. 1996); in families with reading disorder, total CC area and area of CC body correlated positively with oral reading skill, even when controlling for gender and IQ (Fine et al. 2007); in hildren with a range of reading skill, FA of splenium correlated negatively correlated with reading skill (Dougherty et al. 2007; Odegard et al. 2009) |
ADHD | Case reports involving callosal dysgenesis and ADHD (Roessner et al. 2004); Small area (Hynd et al. 1991; Hill et al. 2003) | Small rostral body in males (Hutchinson et al. 2008) | No significant findings | Smaller splenium in mixed-gender sample but no difference from controls in male-only studies (Hutchinson et al. 2008; Valera et al. 2007); Splenium area did not differ from controls when comorbid conditions were excluded (Hill et al. 2003; Semrud-Clikeman et al. 1994; Lyoo et al. 1996) | Reduced left to right transcallosally mediated motor inhibition in children with ADHD (Buchmann et al. 2003; Gilbert et al. 2004; Moll et al. 2000); Slower right-to-left transfer in adults with inattentive-type ADHD and faster left-to-right transfer in adults with combined-type ADHD (Rolfe et al. 2007); rostrum area was negatively correlated with hyperactivity and impulsivity in males children with ADHD (Giedd et al. 1994) |
Autism | Small area (Alexander et al. 2007; Egaas et al. 1995; Manes et al. 1999; Boger-Megiddo et al. 2006); Low FA (Alexander et al. 2007) | Small anterior area (Manes et al. 1999; Kilian et al. 2008; Hardan et al. 2000; Chung et al. 2004; Vidal et al. 2006; Just et al. 2007); Low FA of genu (Alexander et al. 2007; Barnea-Goraly et al. 2004; Keller et al. 2007) | Low FA in body (Barnea-Goraly et al. 2004) and posterior midbody (Keller et al. 2007) | Small posterior area (Piven et al. 1997; Egaas et al. 1995; Haas et al. 1996; Waiter et al. 2005; Just et al. 2007; Vidal et al. 2006); Low FA in splenium (Alexander et al. 2007) | Genu area positively correlated with fronto-parietal connectivity (Just et al. 2007) |
Tourette’s | Small area and low FA for entire CC (Plessen et al. 2006) | No significant findings | No significant findings | No significant findings | Non-significant positive correlation between tic severity and both area and FA of the anterior callosal sections (Plessen et al. 2006) |