Article

Widespread sensorimotor and frontal cortical atrophy in Amyotrophic Lateral Sclerosis

Dept. of Neurology, Medical School Hannover, Hannover, Germany.
BMC Neurology (Impact Factor: 2.04). 04/2006; 6(1):17. DOI: 10.1186/1471-2377-6-17
Source: PubMed

ABSTRACT

Widespread cortical atrophy in Amyotrophic Lateral Sclerosis (ALS) has been described in neuropathological studies. The presence of cortical atrophy in conventional and scientific neuroimaging has been a matter of debate. In studies using computertomography, positron emission tomography, proton magnetic resonance spectroscopy and conventional T2-weighted and proton-weighted images, results have been variable. Recent morphometric studies by magnetic resonance imaging have produced conflicting results regarding the extent of grey and white matter involvement in ALS patients.
The authors used optimized voxel-based morphometry as an unbiased whole brain approach to detect differences between regional grey and white matter volumes. Seventeen patients with a diagnosis of ALS according to El-Escorial criteria and seventeen age-matched controls received a high resolution anatomical T1 scan.
In ALS patients regional grey matter volume (GMV) reductions were found in the pre- and postcentral gyrus bilaterally which extended to premotor, parietal and frontal regions bilaterally compared with controls (p < 0.05, corrected for the entire volume). The revised ALS functional rating scale showed a positive correlation with GMV reduction of the right medial frontal gyrus corresponding to the dorsolateral prefrontal cortex. No significant differences were found for white matter volumes or when grey and white matter density images were investigated. There were no further correlations with clinical variables found.
In ALS patients, primary sensorimotor cortex atrophy can be regarded as a prominent feature of the disease. Supporting the concept of ALS being a multisystem disorder, our study provides further evidence for extramotor involvement which is widespread. The lack of correlation with common clinical variables probably reflects the fact that heterogeneous disease processes underlie ALS. The discrepancy within all published morphometric studies in ALS so far may be related to differences in patient cohorts and several methodological factors of the data analysis process. Longitudinal studies are required to further clarify the time course and distribution of grey and white matter pathology during the course of ALS.

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    • "Whole-brain based methods provide promising ways of characterizing the neural basis of the non-motor symptoms in ALS. Notably, the majority of existing morphometric studies on ALS was conducted through VBM, reporting focal loss of grey and white matter in some specific brain regions (Grosskreutz et al. 2006; Bede et al. 2013). The interpretation of VBM results can be difficult given that an actual physical characteristic is not measured directly (Singh et al. 2006). "
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    • "The involvement of the posterior limb of the internal capsule that we observed has been previously highlighted in relation to prognosis [21]. The changes in frontal areas are in line with bilateral frontal atrophy in VBM [8], [10], [12], [13], an frontally increased diffusivity [22], [23] and post mortem studies [24]. Also VBI confirms that the corpus callosum, which connects orbitofrontal and frontal cortices, is consistently involved in ALS pathology [25]. "
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    • "Several studies described structural neurodegenerative alterations in ALS not only within motor areas, but also across multiple frontotemporal, limbic or subcortical structures (Agosta et al., 2010; Anderson et al., 1995; Grosskreutz et al., 2006; Kato et al., 1997; Neumann et al., 2006; Takeda et al., 2009; Tsermentseli et al., 2012; Wightman et al., 1992). As for the functional results, the pattern of changes was quite inconsistent across studies, probably due to differences in the disease stages of the patient populations. "
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