A. Klistorner

Axonal loss and myelin in early ON loss in postacute optic neuritis

To investigate the relation between retinal nerve fiber layer (RNFL) thickness and latency and amplitude of multifocal visual‐evoked potentials (mfVEPs) in the postacute stage of optic neuritis in patients with early or possible multiple sclerosis.

Axonal loss in non–optic neuritis eyes of patients with multiple sclerosis linked to delayed visual evoked potential

Objective: Recent studies demonstrate significant thinning of the retinal nerve fiber layer (RNFL) in multiple sclerosis (MS) non–optic neuritis (MS-NON) eyes. However, the pathologic basis of this reduction is not clear. The aim of the current study was to investigate the relationship of the RNFL thickness in MS-NON eyes with latency delay of the multifocal visual evoked potential (mfVEP), a surrogate marker of the visual pathway demyelination. Methods: Total and temporal RNFL thickness and latency of the mfVEP in 45 MS-NON eyes of 45 patients with relapsing-remitting MS and 25 eyes of age- and gender-matched controls were measured and analyzed. Results: There was significant reduction of total and temporal RNFL thickness (p = 0.015 and p = 0.006, respectively) and significant latency delay (p < 0.0001) in MS-NON eyes. Both total and temporal RNFL thickness were associated with latency of the mfVEP (r2 = 0.43, p < 0.0001 and r2 = 0.36, p = 0.001, respectively). MS-NON eyes with normal latency (n = 26) showed no significant reduction of RNFL thickness compared with controls (p = 0.44 and p = 0.1 for total and temporal RNFL, respectively), whereas eyes with delayed latency (n = 19) demonstrated significantly thinner RNFL (p = 0.001 and p = 0.0005). MS-NON eyes with delayed latency also had significantly thinner RNFL compared with those with normal latencies (p = 0.013 and p = 0.02). In patients with no previous optic neuritis in either eye, delayed latency and reduced RNFL were bilateral whenever present. Conclusions: The study demonstrated significant association between RNFL loss and a latency delay of the mfVEP in MS-NON eyes.

Inner nuclear layer thickening is inversley proportional to retinal ganglion cell loss in optic neuritis.

Aim To examine the relationship between retinal ganglion cell loss and changes in the inner nuclear layer (INL) in optic neuritis (ON). Methods 36 multiple sclerosis (MS) patients with a history of ON and 36 age and sex-matched controls underwent Optical Coherence Tomography. The paramacular retinal nerve fiber layer (RNFL), combined ganglion cell and inner plexiform layers (GCL/IPL) and inner nuclear layer (INL) thickness were measured at 36 points around the fovea. To remove inter-subject variability, the difference in thickness of each layer between the ON and fellow eye of each patient was calculated. A topographic analysis was conducted. Results The INL of the ON patients was thicker than the controls (42.9µm versus 39.6µm, p=0.002). ON patients also had a thinner RNFL (27.8µm versus 32.2µm, p<0.001) and GCL/IPL (69.3µm versus 98.1µm, p<0.001). Among the controls, there was no correlation between RNFL and GCL/IPL as well as RNFL and INL, but a positive correlation was seen between GCL/IPL and INL (r=0.65, p<0.001). In the ON group, there was a positive correlation between RNFL and GCL/IPL (r=0.80, p<0.001) but a negative correlation between RNFL and INL (r=-0.61, p<0.001) as well as GCL/IPL and INL (r=-0.44, p=0.007). The negative correlation between GCL/IPL and INL strengthened in the ON group when inter-subject variability was removed (r=-0.75, p<0.001). Microcysts within the INL were present in 5 ON patients, mainly in the superior and infero-nasal paramacular regions. While patients with microcysts lay at the far end of the correlation curve between GCL/IPL and INL (i.e. larger INL and smaller GCL/IPL compared to other patients), their exclusion did not affect the correlation (r= -0.76, p<0.001). Conclusions INL enlargement in MS-related ON is associated with the severity of GCL loss. This is a continuous relationship and patients with INL microcysts may represent the extreme end of the scale.

A comparison of multifocal visual evoked potentials with conventional full-field pattern reversal stimulation

drome was considered and aspirin prescribed. At age 14, he developed paraesthesiae of the left hand and then an acute right foot drop. Nerve conduction studies demonstrated an asymmetrical sensori-motor axonal neuropathy: right deep peroneal to EDB motor CV 46.6 m/s, CMAP 1.05 mV, no conduction block found, left deep peroneal to EDB motor CV 49.4 m/s, CMAP 4.2 mV, left sural SNAP not obtained, right sural SNAP 7.2 lV, CV 47.2 m/s, left median sensory CV 55.8 m/s, SNAP 15.6 lV. ESR was 25 mm/h. ANA, ANCA, ENA and antiphospholipid antibodies were negative. Right sural nerve biopsy confirmed a florid necrotizing vasculitis. Conclusion: The neurophysiological and pathological findings established the diagnosis of mononeuritis multiplex due to vasculitic neuropathy. Significance: The combination of cutaneous, central and peripheral nervous system vasculitis has not previously been reported in the paediatric population. This probably represents a rare genetic disorder.