Friday, May 21, 2010
Franklin Hall B Level 4 (Philadelphia Marriott Downtown)
2:00 PM
Background: While music and language are known to recruit overlapping neural systems in healthy subjects, music processing is often preserved and may even be enhanced in ASD despite impairments in language. This divergence raises the question of how these two systems are organized in ASD.
Objectives: We combined functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) to investigate the functional and structural organization of language and music in ASD and to determine whether music in ASD recruits areas that overlap with typical language pathways.
Methods: Speech and music stimuli (with and without vocals) were presented passively during fMRI to investigate functional neural responses to language and music. fMRI scans were acquired from 12 ASD children (mean age=12.40, SD=4.69) and 12 age-matched controls (mean age=12.06, SD=4.03). DTI scans were acquired from 16 ASD children (mean=11.02, SD=3.72) and 16 age-matched controls (mean age=11.17, SD=4.39). DTI tractography was used to identify white-matter pathways originating from the auditory cortex. To determine if pathways typically associated with language are “miswired” or attenuated in ASD, we compared the termination points and integrity (mean fractional anisotropy (FA)) of isolated tracts between control and ASD groups. To investigate the involvement of specific tracts with language or music function, we used covariation analyses to determine relationships between functional activity and structural integrity.
Results: During speech presentation, ASD children showed decreased activation in Broca’s area relative to control children. In contrast, music stimuli (with and without vocals) engaged Broca’s area in ASD children corresponding to regions activated for speech in controls. Tractography analyses isolated dorsal and ventral projections originating from the auditory cortex for both ASD and controls. Dorsal pathways correspond to the arcuate fasciculus and ventral pathways to the inferior occipitofrontal fasciculus, both of which are implicated in normal language functioning. These pathways terminated within the same areas in the inferior frontal gyrus for both groups, indicating that these connections were not “miswired” in ASD. However, comparisons of the integrity (mean FA) of the tracts showed an attenuated left dorsal pathway in ASD relative to controls (p<0.05). In ASD, Broca’s activity during music conditions overlapped with terminations of dorsal pathways and also correlated with the integrity of the attenuated dorsal path. However, during speech stimulation the integrity of the dorsal path did not correlate with activation in Broca’s area.
Conclusions: We demonstrate that music engages Broca’s area to a greater extent than language in low-functioning ASD children via impaired left dorsal projections typically associated with language processing. Findings of music-specific access to impaired language pathways suggests neurobiological validity for music therapies in children with ASD and may guide the development of future treatments for language disabilities in general.
Objectives: We combined functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) to investigate the functional and structural organization of language and music in ASD and to determine whether music in ASD recruits areas that overlap with typical language pathways.
Methods: Speech and music stimuli (with and without vocals) were presented passively during fMRI to investigate functional neural responses to language and music. fMRI scans were acquired from 12 ASD children (mean age=12.40, SD=4.69) and 12 age-matched controls (mean age=12.06, SD=4.03). DTI scans were acquired from 16 ASD children (mean=11.02, SD=3.72) and 16 age-matched controls (mean age=11.17, SD=4.39). DTI tractography was used to identify white-matter pathways originating from the auditory cortex. To determine if pathways typically associated with language are “miswired” or attenuated in ASD, we compared the termination points and integrity (mean fractional anisotropy (FA)) of isolated tracts between control and ASD groups. To investigate the involvement of specific tracts with language or music function, we used covariation analyses to determine relationships between functional activity and structural integrity.
Results: During speech presentation, ASD children showed decreased activation in Broca’s area relative to control children. In contrast, music stimuli (with and without vocals) engaged Broca’s area in ASD children corresponding to regions activated for speech in controls. Tractography analyses isolated dorsal and ventral projections originating from the auditory cortex for both ASD and controls. Dorsal pathways correspond to the arcuate fasciculus and ventral pathways to the inferior occipitofrontal fasciculus, both of which are implicated in normal language functioning. These pathways terminated within the same areas in the inferior frontal gyrus for both groups, indicating that these connections were not “miswired” in ASD. However, comparisons of the integrity (mean FA) of the tracts showed an attenuated left dorsal pathway in ASD relative to controls (p<0.05). In ASD, Broca’s activity during music conditions overlapped with terminations of dorsal pathways and also correlated with the integrity of the attenuated dorsal path. However, during speech stimulation the integrity of the dorsal path did not correlate with activation in Broca’s area.
Conclusions: We demonstrate that music engages Broca’s area to a greater extent than language in low-functioning ASD children via impaired left dorsal projections typically associated with language processing. Findings of music-specific access to impaired language pathways suggests neurobiological validity for music therapies in children with ASD and may guide the development of future treatments for language disabilities in general.