Background: and Purpose Nonfluent variant primary progressive aphasia (nfvPPA) is a neurodegenerative disorder characterized by the progressive deterioration of language functions that typically appears with atrophy predominating in the left peri-insular region (leftnfvPPA) on imaging. While both left-dominant and right-dominant presentations have been reported in semantic variant primary progressive aphasia, the other language presentation of frontotemporal dementia, no case series of nfvPPA with predominantly right-sided atrophy of the peri-insular region (right-nfvPPA) have been reported previously. This study explored whether such entities exist and what their clinical features might be. Methods: A retrospective review of brain imaging data obtained from an established cohort of patients diagnosed with nfvPPA was performed to identify right-nfvPPA cases, followed by detailed analyses of their clinical profiles and imaging results compared to matched typical leftnfvPPA cases and healthy control group. Results: Four of 55 individuals meeting the consensus diagnostic criteria for nfvPPA demonstrated right-nfvPPA. No significant differences were noted in their clinical and neuropsychological profiles. Detailed imaging analyses demonstrated that the individuals with right-nfvPPA did not demonstrate atrophy of the anterior cingulate gyrus, unlike those in the left-nfvPPA group. Conclusions This study has revealed several intriguing differences between right-nfvPPA and left-nfvPPA, particularly in the prevalence of impairments in motor speech and naming as well as imaging differences. These findings warrant further exploration in a larger cohort to improve our understanding of neural network organization and its dysfunction in neurodegenerative disorders.

Background: and Purpose Nonfluent variant primary progressive aphasia (nfvPPA) is a neurodegenerative disorder characterized by the progressive deterioration of language functions that typically appears with atrophy predominating in the left peri-insular region (leftnfvPPA) on imaging. While both left-dominant and right-dominant presentations have been reported in semantic variant primary progressive aphasia, the other language presentation of frontotemporal dementia, no case series of nfvPPA with predominantly right-sided atrophy of the peri-insular region (right-nfvPPA) have been reported previously. This study explored whether such entities exist and what their clinical features might be. Methods: A retrospective review of brain imaging data obtained from an established cohort of patients diagnosed with nfvPPA was performed to identify right-nfvPPA cases, followed by detailed analyses of their clinical profiles and imaging results compared to matched typical leftnfvPPA cases and healthy control group. Results: Four of 55 individuals meeting the consensus diagnostic criteria for nfvPPA demonstrated right-nfvPPA. No significant differences were noted in their clinical and neuropsychological profiles. Detailed imaging analyses demonstrated that the individuals with right-nfvPPA did not demonstrate atrophy of the anterior cingulate gyrus, unlike those in the left-nfvPPA group. Conclusions This study has revealed several intriguing differences between right-nfvPPA and left-nfvPPA, particularly in the prevalence of impairments in motor speech and naming as well as imaging differences. These findings warrant further exploration in a larger cohort to improve our understanding of neural network organization and its dysfunction in neurodegenerative disorders.

Background: and Purpose Nonfluent variant primary progressive aphasia (nfvPPA) is a neurodegenerative disorder characterized by the progressive deterioration of language functions that typically appears with atrophy predominating in the left peri-insular region (leftnfvPPA) on imaging. While both left-dominant and right-dominant presentations have been reported in semantic variant primary progressive aphasia, the other language presentation of frontotemporal dementia, no case series of nfvPPA with predominantly right-sided atrophy of the peri-insular region (right-nfvPPA) have been reported previously. This study explored whether such entities exist and what their clinical features might be. Methods: A retrospective review of brain imaging data obtained from an established cohort of patients diagnosed with nfvPPA was performed to identify right-nfvPPA cases, followed by detailed analyses of their clinical profiles and imaging results compared to matched typical leftnfvPPA cases and healthy control group. Results: Four of 55 individuals meeting the consensus diagnostic criteria for nfvPPA demonstrated right-nfvPPA. No significant differences were noted in their clinical and neuropsychological profiles. Detailed imaging analyses demonstrated that the individuals with right-nfvPPA did not demonstrate atrophy of the anterior cingulate gyrus, unlike those in the left-nfvPPA group. Conclusions This study has revealed several intriguing differences between right-nfvPPA and left-nfvPPA, particularly in the prevalence of impairments in motor speech and naming as well as imaging differences. These findings warrant further exploration in a larger cohort to improve our understanding of neural network organization and its dysfunction in neurodegenerative disorders.

BACKGROUND AND PURPOSE: This study investigated the structural and functional changes in the motor system in amyotrophic lateral sclerosis (ALS; n=25) and behavioral-variant fronto-temporal dementia (bvFTD; n=17) relative to healthy controls (n=37). METHODS: Structural changes were examined using a region-of-interest approach, applying voxel-based morphometry for gray-matter changes and diffusion tensor imaging for white-matter changes. Functional changes in the motor system were elucidated using threshold-tracking transcranial magnetic stimulation (TMS) measurements of upper motor-neuron excitability. RESULTS: The structural analyses showed that in ALS there were more white-matter changes in the corticospinal and motor-cortex regions and more gray-matter changes in the cerebellum in comparison to controls. bvFTD showed substantial gray- and white-matter changes across virtually all motor-system regions compared to controls, although the brainstem was affected less than the other regions. Direct comparisons across patient groups showed that the gray- and white-matter motor-system changes inclusive of the motor cortex were greater in bvFTD than in ALS. By contrast, the functional integrity of the motor system was more adversely affected in ALS than in bvFTD, with both patient groups showing increased excitability of upper motor neurons compared to controls. CONCLUSIONS: Cross-correlation of structural and functional data further revealed a neural dissociation of different motor-system regions and tracts covarying with the TMS excitability across both patient groups. The structural and functional motor-system integrities appear to be dissociated between ALS and bvFTD, which represents useful information for the diagnosis of motor-system changes in these two disorders.
Amyotrophic Lateral Sclerosis* ; Brain Stem ; Cerebellum ; Dementia ; Diagnosis ; Diffusion Tensor Imaging ; Frontotemporal Dementia* ; Humans ; Motor Cortex ; Motor Neurons ; Transcranial Magnetic Stimulation