The role of cerebellar abnormalities in neuromyelitis optica--a comparison with multiple sclerosis and healthy controls.

BACKGROUND

In relapsing-remitting multiple sclerosis (RRMS), the cerebellum is a known predilection site for atrophy. Neuromyelitis optica (NMO) is characterized by extensive lesions in the spinal cord and optic nerve; however, cerebellar involvement has been less studied. Secondary degeneration of the spinocerebellar tract could impact the cerebellum in NMO.

OBJECTIVE

We aimed to investigate whether spinal cord and cerebellar volume measures differ between patients with NMO and RRMS.

METHODS

Volumetric analyses of the cerebellum (TCV), the upper cervical cord (UCV) as well as the whole brain (NBV) of age- and gender-matched patients with NMO (n=30; 56% AQP4 +ve) and RRMS (n=25) were performed on 3T brain magnetic resonance imaging (MRI) and compared with 34 healthy controls (HC).

RESULTS

UCV was significantly reduced in NMO patients (6.3 cm(3)) as compared with HC (6.7 cm(3)), while patients with MS had reduced brain volumes compared with HC (NBV=1482 cm(3); p<0.001; TCV=188 cm(3); p=0.042), but UCV close to normal values. Patients with RRMS and NMO differed in NBV (p=0.001; lower in RRMS) and by trend (towards reduction in RRMS) in cerebellar volume (p=0.06).

CONCLUSIONS

While atrophy seems to be diffuse in MS patients, a rather focussed pattern with predominant involvement of the UCV was observed in NMO patients.