Early bilateral and massive compromise of the frontal lobes

Abstract

The frontal lobes are one of the most complex brain structures involved in both domain-general and specific functions. The goal of this work was to assess the anatomical and cognitive affectations from a unique case with massive bilateral frontal affectation. We report the case of GC, an eight-year old child with nearly complete affectation of bilateral frontal structures and spared temporal, parietal, occipital, and cerebellar regions. We performed behavioral, neuropsychological, and imaging (MRI, DTI, fMRI) evaluations. Neurological and neuropsychological examinations revealed a mixed pattern of affected (executive control/abstraction capacity) and considerably preserved (consciousness, language, memory, spatial orientation, and socio-emotional) functions. Both structural (DTI) and functional (fMRI) connectivity evidenced abnormal anterior connections of the amygdala and parietal networks. In addition, brain structural connectivity analysis revealed almost complete loss of frontal connections, with atypical temporo-posterior pathways. Similarly, functional connectivity showed an aberrant frontoparietal network and relative preservation of the posterior part of the default mode network and the visual network. We discuss this multilevel pattern of behavioral, structural, and functional connectivity results. With its unique pattern of compromised and preserved structures and functions, this exceptional case offers new constraints and challenges for neurocognitive theories.

Neurocognitive patterns across genetic levels in behavioral variant frontotemporal dementia: a multiple single cases study

“…However, to reduce a potential statistical bias when we run comparisons, we used the Crawford index, which allows us to assess differences between single cases and control samples with statistics values [23,24,110]. The Crawford index has also proved statistical value in assessing braingenetics-behavior interactions between single cases of patients with neurologic conditions in comparisons with control groups [60,61,[111][112][113][114].…”

Progressive Compromise of Nouns and Action Verbs in Posterior Cortical Atrophy

“…More generally, our study meets the requisite of incorporating single-subject studies in cognitive neuroscience, as a crucial complement of group-based neuroimaging research ( Dubois and Adolphs, 2016 ). As shown by previous works, establishing particular patterns of compromised and spared functions given circumscribed MRI/fMRI abnormalities in theoretically relevant single cases is highly useful for tracking particular forms of functional organization, impairment, and re-organization ( Baez et al, 2013 ; Sedeño et al, 2014 ; Couto et al, 2015 ; García et al, 2017a , c ; Ibáñez et al, 2018 ). A dialog between individual-level findings and group-based outcomes is critical to foster progress in both theoretical and applied areas of the field.…”