Cerebellar hypoperfusion in anti-NF155 antibody-positive nodopathy: a retrospective case series using brain perfusion
Hanna Okada1, Yuji Tomizawa1, Yasunobu Hoshino1
1Department of Neurology, Faculty of Medicine, Juntendo University, Tokyo, Japan.
Introduction:
Anti-neurofascin-155 (NF155) antibody-positive nodopathy is a distinct autoimmune neuropathy characterized by sensory ataxia, tremor, and poor response to intravenous immunoglobulin (IVIg). Although classically considered a peripheral disorder, central nervous system (CNS) involvement has been suggested, but functional neuroimaging correlates remain unclear.
Methods:
We retrospectively analyzed seven male patients with NF155 antibody-positive nodopathy. Clinical and electrophysiological assessments were performed, and all patients underwent brain perfusion single-photon emission computed tomography (SPECT) using 123I-IMP iodoamphetamine. Imaging data were processed using three-dimensional stereotactic surface projection (3D-SSP) and compared to an age-matched database. Cerebellar hypoperfusion was defined as regional z-scores ≤ -2.0.
Results:
The mean patient age was 39.0 ± 12.9 years, and mean disease duration was 5.0 ± 3.9 years. Tremor was documented in all patients at some point during the disease course and was predominantly postural or kinetic. Cerebellar hypoperfusion was identified in six patients (86%), involving the cerebellum bilaterally in most cases, with variable degrees of asymmetry across individuals. No correlation was found between hypoperfusion and disease duration or age.
Conclusion:
Cerebellar hypoperfusion was frequently observed in this single-center case series of anti-NF155 antibody-positive nodopathy. These findings are descriptive and hypothesis-generating, and compatible with a possible association between cerebellar perfusion abnormalities and tremor. Larger prospective studies are warranted to validate these observations and explore their clinical implications.
