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VEPs 2
Visual evoked potentials 2
Question | Answer |
---|---|
The typical distance from the light source to the patient in flashing VEPs is __ - __ cm | 30, 45 |
Background luminance with flashing VEPs is kept __ (low / high) | low |
A stimulus luminance for flashing VEPs increases, the amplitude of the VEP __ (increases/decreases) and latency __ (increases/decreases) | increases, decreases |
Flashing VEPs are set at a frequency of no faster than __ per secon | 2 |
The first channel for a flashing VEP | MO-ear |
The second channel for a flashing VEP | LO-er |
The third channel for a flashing VEP | RO-ear |
A rhythmic after discharge is seen with flashing VEP after approximately __ msec | 240 |
Early peaks with a flash VEP are maximal over the __ cortex; later peaks are maximal near the __ | occipital; vertex |
Up to __% of normal subjects have no response on one side of the head with flash VEPs despite the absence of pathology | 5 |
The flash VEP can be composed of up to __ peaks with varying polarity, amplitude and latency | 7 |
The normal flash VEP is composed of a major positive peak with a latency between __ and __ msex and a major negative peak with a latency between __ and __ msec | 50, 100, 100, 250 |
After __ weeks conceptual age, an occipitally negative negative peak is seen at 200-300 msec on flash VEP | 24 |
At 24 weeks EGA, an occipitally negative peak is seen on flash VEP at __ - __ msec | 200, 300 |
At __ - __ weeks EGA, a positive peak precedes the negative peak on flash VEP with a latency of < 200 msec | 32, 35 |
As pupil size increases, stimulus intensity __ (increases/decreases) | increases |
The criteria for an abnormal flash VEP | Absence of a response with stimulation of one eye |