Brain MRI shows white matter sparing in Kennedy's disease and slow‐progressing lower motor neuron disease

Abstract

The extent of central nervous system involvement in Kennedy's disease (KD) relative to other motor neuron disease (MND) phenotypes still needs to be clarified. In this study, we investigated cortical and white matter (WM) MRI alterations in 25 patients with KD, compared with 24 healthy subjects, 25 patients with sporadic amyotrophic lateral sclerosis (ALS), and 35 cases with lower motor neuron‐predominant disease (LMND). LMND patients were clinically differentiated into 24 fast and 11 slow progressors. Whole‐brain cortical thickness, WM tract‐based spatial statistics and corticospinal tract (CST) tractography analyses were performed. No significant difference in terms of cortical thickness was found between groups. ALS patients showed widespread decreased fractional anisotropy and increased mean (MD) and radial diffusivity (radD) in the CST, corpus callosum and fronto‐temporal extra‐motor tracts, compared with healthy controls and other patient groups. CST tractography showed significant alterations of DT MRI metrics in ALS and LMND‐fast patients whereas KD and LMND‐slow patients were comparable with healthy controls. Our study demonstrated the absence of WM abnormalities in patients with KD and LMND‐slow, in contrast with diffuse WM damage in ALS and focal CST degeneration in LMND‐fast, supporting the use of DT MRI measures as powerful tools to differentiate fast‐ and slow‐progressing MND syndromes, including KD.

Increased cerebral integrity metrics in poliomyelitis survivors: putative adaptation to longstanding lower motor neuron degeneration

“…Attempted cerebral adaptation to slowly progressive LMN degeneration has been observed in other neurological conditions such as SMA [55] and lowermotor neuron predominant ALS. [56,63] Similarly to our findings, the absence of cerebral pathology was noted in spinal-bulbar muscular atrophy (SBMA) [64] and other lower-motor neuron predominant motor neuron disease cohorts. [54] Neuroplasticity is a broad term which refers to the malleable properties of the brain to rewire and reorganise its structure, function and connections throughout life in response to experience and injury.…”

Pathological neural networks and artificial neural networks in ALS: diagnostic classification based on pathognomonic neuroimaging features

“…Only total volumes of subcortical structures were explored as input variables in this study, even though the assessment of specific amygdalar nuclei, thalamic nuclei or hippocampal subfields may enhance the discrimination of ALS form other neurodegenerative conditions [72][73][74][75]. Moreover, our model only evaluated cerebral metrics, therefore LMN pathology is not accounted for and discrimination from LMN-predominant MNDs cannot be reliably assessed [76][77][78][79][80][81][82]. Additional validation of the model with presymptomatic mutation carriers would have tested the classification accuracy of the model further by evaluating subjects with limited disease burden [10,83].…”

Language impairment in motor neuron disease phenotypes different from classical amyotrophic lateral sclerosis: a review

“…Similarly to the study by Consonni et al (2013), Spinelli et al's (2016) investigation took into account highly heterogeneous patients as far as etiology is concerned. In the study by Agosta et al (2019) [see above, 3.2.2. ], prLMND patients proved to perform normally as a group on the object-naming task of the BADA, whereas defective individual-level performances could be inferred if comparing mean action-naming scores (25.8±2.5) to the original cut-off value -i.e.,…”