Sparse multifocal stimuli for the detection of multiple sclerosis

Abstract

We compared the diagnostic capabilities of contrast reversal and sparse pattern pulse stimulation for dichoptic multifocal visual evoked potentials (mfVEPs) measured in normal subjects and multiple sclerosis (MS) patients. Multifocal responses were obtained from 27 normal subjects and 50 relapsing-remitting patients, 26 of whom had experienced optic neuritis (ON+). The patient groups were matched for length of disease and number of clinical attacks. Compared with the responses of normal subjects those of MS patients had significantly smaller response amplitudes, lower signal-to-noise ratios, more complex response waveforms, and longer response delays. The effects were larger for sparser stimuli. Sensitivities and specificities for the different stimulus types were estimated from receiver operator characteristic (ROC) plots. Bootstrap estimates of the accuracies of the ROCs for the most promising measure, the template delays, indicated the sparsest stimulus would deliver 92% sensitivity at a false-positive rate of 0%. In contrast, at 92% sensitivity the conventional mfVEP stimulus misdiagnosed more than 20% of the normal population. The results were similar for patients with no history of ON (ON-). In performing well in patients with no history of ON, the sparse mfVEPs seem to measure progressive damage associated with axon and gray matter losses rather than damage associated with a history of serious inflammation.

A comparison of multifocal and conventional visual evoked potential techniques in patients with optic neuritis/multiple sclerosis

“…However, it should be possible to substantially shorten the mfVEP test for clinical purposes. For example, Ruseckaite et al [16] reported a sensitivity/specificity of 92%/ 100% using a sparse mfVEP paradigm and under 3 min of recording. In any case, cVEP testing is more readily available than mfVEP testing.…”

“…It is therefore not unreasonable to assume that although the cVEP may detect wide-spread areas of demyelinization, it may fail to detect localized changes. Using the sparse stimulus mfVEP paradigm, developed by James and colleagues [14][15][16], Ruseckaite et al [16] estimated a 92% sensitivity, with a specificity of 100%, for detecting MS. However, their results were not compared to cVEP recordings.…”

Multifocal Visual Evoked Responses to Dichoptic Stimulation Using Virtual Reality Goggles: Multifocal VER to Dichoptic Stimulation

“…Multifocal VEP responses with dichoptic stimulation have been recorded before using a liquid crystal polarizing shutter with associated polarizing spectacles [12,[17][18][19]. The method reported by us, however, does not require the patient to wear polarizing glasses (which dramatically reduce stimulus luminance), and uses portable virtual reality goggles rather than the large monitor screen.…”

“…Sato et al [16] reported that pseudorandom binary sequences (PRBS) could be used to independently stimulate right and left eyes, and the response of each eye could be calculated by crosscorrelating the resultant response with the PRBS. Recently, James and co-workers [12,[17][18][19] reported recording multifocal (8 or 60 regions) pattern VEP for each eye under dichoptic stimulation conditions using a liquid crystal polarizing shutter and associated polarizing spectacles, which, however, significantly reduces luminance of the stimulus. The current study further explores the possibilities and nuances of recording mfVEP from each eye under dichoptic testing conditions.…”

“…Also referred to as 'objective perimetry', this test demonstrated 95-97% sensitivity with a minimum specificity of 92.2% for glaucoma [5], and in a significant number of cases detected a scotoma in the fellow eye where Humphrey Field Analyzer (HFA) results were normal [9]. Recently, analysis of mfVEP latency in patients with optic neuritis who, according to McDonalds criteria [10] were classified as 'possible multiple sclerosis', indicated that mfVEP delays may predict probability of conversion to multiple sclerosis [11,12].…”