Hohberger Bettina, Kremers Jan, Horn Folkert K
Department of Ophthalmology and Eye Hospital, University Hospital Erlangen, Germany.
Transl Vis Sci Technol. 2019 Feb 28;8(1):24. doi: 10.1167/tvst.8.1.24. eCollection 2019.
It has been shown that multifrequency stimulation with multifocal electroretinography can reduce recording time without a loss in signal-to-noise ratio. Here, we studied the applicability of multifrequency stimulations for steady-state visually evoked potential (VEP) recordings.
Multifrequency VEPs were recorded monocularly from 10 healthy subjects using pattern-reversal stimuli. The reversal frequency varied between 5 and 30 Hz. Pattern-reversal checkerboard stimuli were generated using four square arrays, each containing 100 light-emitting diodes (LEDs), positioned in four quadrants. Each array had a temporal frequency that differed slightly from the nominal frequency. The long duration of the data acquisition ensured that the slightly different stimulus frequencies in the four LED arrays can be resolved and that the responses to the stimulus in each array can be distinguished (e.g., with a frequency resolution: 0.011 Hz at 12 Hz). The best response from the four recording electrode configuration, defined as the recording with the maximal signal-to-noise ratio, was used for further analysis. Algorithmic latencies were calculated from the ratio of phase data and frequencies in a range of 4 and 20 Hz.
Quadrant-VEPs with simultaneous pattern-reversal stimulation yielded a significant dependency on temporal frequency and stimulus location. The frequency range leading to the maximal response amplitude was between 10 and 12 Hz. Response phases decreased approximately linearly, with increasing temporal frequency suggesting a mean algorithmic latency between 112 and 126 ms.
Multifrequency stimulation using LED arrays is an efficient method for recording pattern-reversal VEPs while all stimuli are presented at the same time.
Simultaneously recorded VEPs as performed by the multi-frequency method can be used for objective measurements of visual field defects.
多焦视网膜电图的多频率刺激已被证明可以减少记录时间，同时不损失信噪比。在此，我们研究了多频率刺激在稳态视觉诱发电位（VEP）记录中的适用性。
使用模式反转刺激，对10名健康受试者单眼记录多频率VEP。反转频率在5至30赫兹之间变化。模式反转棋盘格刺激由四个正方形阵列产生，每个阵列包含100个发光二极管（LED），位于四个象限。每个阵列的时间频率与标称频率略有不同。长时间的数据采集确保了四个LED阵列中略有不同的刺激频率能够被分辨出来，并且每个阵列中对刺激的反应能够被区分（例如，频率分辨率：在12赫兹时为0.011赫兹）。来自四个记录电极配置的最佳反应，定义为具有最大信噪比的记录，用于进一步分析。算法潜伏期通过4至20赫兹范围内的相位数据与频率之比计算得出。
同时进行模式反转刺激的象限VEP对时间频率和刺激位置有显著依赖性。导致最大反应幅度的频率范围在10至12赫兹之间。反应相位随着时间频率的增加大致呈线性下降，表明平均算法潜伏期在112至126毫秒之间。
使用LED阵列的多频率刺激是一种在所有刺激同时呈现时记录模式反转VEP的有效方法。
通过多频率方法同时记录的VEP可用于视野缺损的客观测量。
