| Alien limb phenomenon | The affected hand appears to act independently of the patient's will, with involuntary grasping, manipulation, or avoidance behaviors[^3] |
| Impaired bimanual coordination | Inability to coordinate purposeful movements between the two hands, despite intact individual limb function |
| Callosal apraxia | Specific deficits in executing learned motor sequences when using the contralesional hand to command from the ipsilesional side |
| Tactile agnosia | Inability to recognize familiar objects by touch despite intact primary somatosensory function |
| Astereognosis | Loss of stereognosis—identifying objects by their weight, texture, and three-dimensional properties |
| Graphesthesia impairment | Inability to recognize letters or numbers drawn on the skin |
| Callosal thinning | Particularly in the anterior and midbody regions, with mean thickness reduction of 30-40% compared to healthy controls |
| Hyperintense signal | Focal T2 hyperintensity within the callosal body reflecting vacuolation and demyelination |
| "Hot cross bun" sign | May be present in CBS with pontine involvement, though more characteristic of multiple system atrophy[^4] |
| Reduced fractional anisotropy | Indicative of disrupted fiber integrity within callosal pathways |
| Increased mean diffusivity | Reflecting axonal loss and vacuolation |
| Reduced streamline count | Demonstrating loss of transcallosal fiber bundles |
| Databases | OMIMOrphanetClinicalTrialsPubMed |