This MRI study was performed to evaluate in vivo alterations of the spinal cord in defined subgroups of motor neuron diseases. Standard MRI examinations of the cervical and thoracic spinal cord in sporadic amyotrophic lateral sclerosis (ALS; n = 39), sporadic lower motor neuron disease (LMND; n = 19), Kennedy’s disease (KD; n = 19) and a control group (n = 96) were analyzed with respect to spinal cord signal changes and the thickness of the spinal cord. No significant changes in thickness or signal alterations were observed when comparing ALS, LMND and control groups with one another. However, in KD patients significant upper spinal cord atrophy was detected at the cervical level as compared with all other groups. At the thoracic level, KD patients had significant upper cord atrophy as compared with controls and LMND. Marked atrophy of the upper spinal cord seems to be a feature of the KD-associated central-peripheral distal axonopathy.

Background/Aims: Degenerative lower motor neuron diseases (LMND) encompass a group of rare clinically and genetically heterogeneous disorders with the hallmark of anterior horn cell degeneration in the spinal cord and brainstem. In a recently proposed classification, LMND were subdivided according to the clinical disease pattern and time course. This study was performed to investigate the clinical practicability of the classification. Methods: In 22 patients with adult LMND (mean disease duration, 24 years), the disease course and detailed clinical, electrophysiological, magnetic resonance imaging, laboratory, and genetic investigations were analyzed. Results: All patients could be assigned to the distinct disease subgroups, i.e. 11 patients to the slowly progressive generalized form (group 1), one to the distal form (group 2), 3 to the segmental distal form (group 3a), and seven to the segmental proximal form (group 3b). Conclusions: The proposed classification was confirmed to be a practicable tool, and additional implications for the classification of LMND could be drawn from the data in our patient sample.

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