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Citation
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Solly EJ, Clough M, McKendrick AM, Foletta P, White OB, Fielding J. Neurology 2020; ePub(ePub): ePub. |
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Abstract
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OBJECTIVE: To determine whether changes to cortical processing of visual information can be objectively evaluated using three simple ocular motor tasks to measure performance in patients with visual snow syndrome (VSS).
METHODS: Sixty four patients with VSS (32 with migraine and 32 with no migraine), and 23 controls participated. Three ocular motor tasks were included: prosaccade (PS), antisaccade (AS), and interleaved antisaccade-prosaccade (AS-PS) tasks. All these tasks have been used extensively in both neurologically healthy and diseased states.
RESULTS: We demonstrated that, compared to controls, the VSS group generated significantly shortened PS latencies (p =.029) and an increased rate of AS errors (p =.001), irrespective of the demands placed on visual processing (i.e., task context). Switch costs, a feature of the AS-PS task, were comparable across groups, and a significant correlation was found between shortened PS latencies and increased AS error rates for VSS patients (r =.404).
CONCLUSION: We identified objective and quantifiable measures of visual processing changes in patients with VSS. The absence of any additional switch cost on the AS-PS task in VSS suggests that the PS latency and AS error differences are attributable to a speeded PS response rather than to impaired executive processes more commonly implicated in poorer AS performance. We propose that this combination of latency and error deficits, in conjunction with intact switching performance will provide a VS behavioural signature that contributes to our understanding of VSS and may assist in determining the efficacy of therapeutic interventions.
Language: en |