Neural organization of speech production: A lesion-based study of error patterns in connected speech

Brielle C Stark; Alexandra Basilakos; Gregory Hickok; Chris Rorden; Leonardo Bonilha; Julius Fridriksson

1B: Prior to multiple comparison correction, a comparison of left hemisphere lesion proportion damage to parcels between task groups shown on axial slices with a left hemisphere sagittal cross-slice. Parcellation was from the Johns Hopkins University atlas (Faria et al., 2012) , which contained gray-and white-matter parcels (182 in the whole brain). When comparing lesion damage to each parcel between the CS and PNT task groups, there was not a significant difference between lesion proportion damage to a parcel after multiple comparison correction (FDR; q=0.05). Prior to multiple comparison correction, six dorsal stream parcels were significantly more damaged in the PNT task group than the CS task group at p<0.05 (z>1.96); these are shown in the figure. P-values for these parcels ranged from p=0.0098 (middle frontal gyrus) to p=0.036 (underlying white matter, internal capsule. aphasia quotient], total words spoken / total items named, apraxia of speech (AOS) score from the Apraxia of Speech Rating Scale (ASRS, Strand et al., 2014) . Note that the CS task group showed significant correlations of paraphasia proportions (neologistic, phonemic, unrelated) with apraxia of speech severity, and this was why apraxia of speech severity was used as a covariate in VLSM analyses for the group. The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. It . https://doi.org/10.1101/544841 doi: bioRxiv preprint 4A: Surface rendering of the significant results of the VLSM analysis for the PNT task group (left) and CS task group (right). Both the PNT and CS task group results, which demonstrate damage significantly associated with each paraphasia type, have variance from lesion volume removed. In the far-right column, we also present results from the CS task group with variance from both lesion volume and apraxia of speech severity removed, as apraxia of speech severity was significantly correlated with neologistic, phonemic and unrelated paraphasias in this group. Lesion damage significantly associated with sound paraphasias (neologistic, phonemic) was only found for the CS task group, and demonstrated a dorsal distribution.