Quick Answer
Evoked potential studies measure how long a signal takes to travel along a sensory pathway, detecting slowing a patient cannot feel. Three pathways can be tested and the study is performed and interpreted at 1691 W. Horizon Ridge Parkway, Suite 100, Henderson NV 89012.
Part ofThis guide sits beneath evoked potential studies, which covers the study itself, how it is performed and what the report should contain.
Evoked Potential Studies in our accredited lab →Key Takeaways
- Three pathways can be tested: visual, auditory and somatosensory.
- Only the visual study asks anything of you, which is sustained gaze on a central point.
- The auditory study needs nothing at all and you may doze through it.
- Wash your hair beforehand and leave nothing in it, and bring distance glasses for a visual study.
- Thirty to ninety minutes depending on how many pathways. Performed at 1691 W. Horizon Ridge Parkway, Suite 100, Henderson NV 89012.
Evoked potentials
Evoked potential studies measure the electrical response of the nervous system to a controlled stimulus — sound, light or a small electrical pulse — and time how long the signal takes to travel its pathway. Slowing can indicate damage imaging does not show.
What the study measures, and the trick that makes it possible
An evoked potential study answers a narrow question precisely: how long does a signal take to travel along a sensory pathway to the brain.
Averaging, and why it is necessary
The brain response to a single flash or click is far smaller than the ordinary background electrical activity around it, so one response cannot be seen. The solution is repetition. The stimulus is delivered hundreds of times, the recording is time-locked to each delivery, and the responses are averaged. Random background activity cancels itself across many repetitions while the consistent response builds into a measurable waveform. That is why these studies involve a repetitive stimulus for several minutes rather than a single event.
What a delay means
Conduction along a healthy pathway takes a predictable time. Where the insulating myelin is damaged, conduction slows and the response arrives late. The measurement is in milliseconds, compared against reference values and against your other side. Its particular usefulness is that a pathway can conduct slowly while you report normal vision, hearing or sensation, so the study detects impairment you cannot feel and an examination may not reveal.
Why it survived modern imaging
A reasonable question, since imaging shows lesions directly and evoked potentials show nothing anatomically. The answer is that the two measure different things. Imaging shows where tissue has changed; an evoked potential shows whether a pathway is still conducting properly. Those can disagree in both directions, and a functional delay in a pathway that looks unremarkable on a scan is genuine information.
| Also considered | How it is distinguished |
|---|---|
| MRI | Shows structural lesions; evoked potentials show whether conduction along the pathway is delayed. |
| Nerve conduction studies | Assess peripheral nerves; evoked potentials assess central sensory pathways. |
| Formal hearing or vision testing | Assesses the organ; evoked potentials assess the nerve pathway behind it. |
| Clinical examination | Detects overt deficit; these studies can detect subclinical slowing. |
The three studies, and how to prepare
01
What brings people in
A question about optic, auditory or somatosensory pathway function, often alongside a demyelination work-up.
02
What the evaluation settles
Whether conduction along a specific sensory pathway is delayed, and on which side.
03
What you leave with
Timed, quantified pathway results interpreted alongside your imaging and examination.
Three pathways, three different studies
Visual, using a black-and-white checkerboard reversing on a screen, one eye at a time. Auditory, using repetitive clicks through headphones, one ear at a time. And somatosensory, using brief electrical pulses at the wrist or ankle that produce a small twitch and a tapping sensation. Which pathway is tested depends entirely on the clinical question, and some patients have one study while others have all three.
The two preparation points that matter
Clean bare hair: wash it beforehand and use no conditioner, oil, gel, spray or dry shampoo, because sensors attach with paste and residue interferes with contact. And bring your distance glasses or contact lenses for a visual study, because the study measures the pathway rather than your refraction and an uncorrected blur affects the result. For an auditory study, disclose hearing loss, hearing aids, prior ear surgery or wax in advance, since each changes how the study is set up and read.
What it feels like
The visual study asks for concentration rather than tolerance: each eye tested separately while you hold your gaze on a central point. It is tiring for the eyes and mildly tedious rather than uncomfortable. The auditory study needs nothing of you at all and you may doze. The somatosensory study feels like tapping with a small muscle twitch. No needles for the visual or auditory studies.
Duration
Roughly thirty minutes for a single pathway including setup, and closer to ninety for all three. The study can be paused if you need a break, which patients often assume is not possible once a recording has started.
The first 30, 60 and 90 days
Step 1
First visit
History and neurological examination, a review of records and prior imaging, and a decision on which studies are actually indicated. You leave with the plan, not just a referral.
Step 2
Within 30 days
Indicated in-office studies are performed and interpreted by the neurologist who ordered them, in our AANEM-accredited laboratories. Results are explained in plain language.
Step 3
60 to 90 days
Follow-up to judge whether the plan is working, adjust it, and coordinate with your referring clinician. Where a diagnosis needs time to confirm, this is where it is revisited.
Attending from Henderson
The Henderson office is at 1691 W. Horizon Ridge Parkway, Suite 100, just off the 215 Beltway, with parking on site. All six in-office studies are performed and interpreted there, so nothing is sent across to Las Vegas. Green Valley, Anthem, Whitney and Boulder City are generally closer to it than to Flamingo Road. Adults 18 and older.
Referred for evoked potentials?
Bring your glasses, arrive with clean bare hair, and mention any hearing history.
The Bottom Line
Bring your glasses, arrive with clean bare hair, and expect concentration rather than discomfort.
Frequently Asked Questions
What does an evoked potential test measure?
How long a nerve signal takes to travel along a sensory pathway to the brain. A stimulus is delivered hundreds of times and the responses averaged, which extracts a measurable waveform from background activity and allows the arrival time to be measured in milliseconds. The averaging is why the study takes as long as it does.
Does it hurt?
The visual and auditory studies involve no discomfort at all, only eye fatigue and loud rapid clicking respectively. The somatosensory study delivers brief pulses at the wrist or ankle that feel like tapping with a small twitch. No needles are used for the visual or auditory studies. Nothing is injected for any of the three.
Should I bring my glasses?
Yes, for a visual study bring the glasses or contact lenses you use for distance. The study measures the pathway rather than your refraction, and an uncorrected blur affects the result. For an auditory study, disclose hearing loss, hearing aids, ear surgery or wax beforehand. Bring a lens prescription if you have one to hand.
How long does it take?
Roughly thirty minutes for a single pathway including setup, and closer to ninety if all three are studied. The study can be paused if you need a break, which patients often assume is not possible once a recording has started. Allow a little longer than the estimate so the appointment is not rushed.
Can it diagnose multiple sclerosis?
Not on its own. It contributes evidence of impaired conduction alongside imaging and the clinical picture. It is a supporting study, and treating a single normal result as an exclusion is the commonest misreading of it. It is most useful where the imaging and the examination together leave the question genuinely open.
Is a BAER the same as a hearing test?
No. A brainstem auditory evoked response measures conduction along the auditory pathway to the brainstem. It is not a substitute for audiometry, which measures hearing thresholds and is a different test for a different question. If hearing is the question you are asking, audiometry rather than this study is what to request.
Why test a pathway where I have no symptoms?
Because finding a delay in a pathway you have no complaints about is often the more significant result. It establishes that impaired conduction is not confined to the area producing symptoms, which changes the clinical picture substantially. It is one of the few situations where testing something that feels fine is the whole point.
Can the study be paused?
Yes. It can be paused if you need a break, which patients often assume is not possible once a recording has started. Tell the technologist rather than pushing through, because drowsiness or discomfort degrades a recording that depends on your attention. A short break costs a few minutes and protects the result.
Where exactly is the Henderson office?
1691 W. Horizon Ridge Parkway, Suite 100, Henderson NV 89012, just off the 215 Beltway, with parking on site. All six in-office studies are performed and interpreted there, so nothing is referred across to the Las Vegas office. Green Valley, Anthem, Whitney and Boulder City are generally closer to it than to West Flamingo Road.
Should I use the Henderson or the Las Vegas office?
Whichever is the shorter drive, since both are fully equipped and hold the same records. West Horizon Ridge Parkway generally suits Green Valley, Anthem and Boulder City; West Flamingo Road suits the west and southwest of the valley. If you can attend either, say so when booking, because availability differs between the two week to week.
How this page was sourced
Practice facts come from Clinical Neurology Specialists directly: that these studies are performed and interpreted at both offices, and that no audiology or imaging service is operated on site. Clinical context is sourced to the organisations listed below.
Latency reference values are deliberately not published, because they depend on age, height and sex and a number without its reference range would mislead a reader holding their own report. Durations quoted are typical and vary by how many pathways are studied. No outcome is promised. Scope is adults 18 and older.
Change log
- 2026-07-28 — page published; clinical content reviewed.
- 2026-07-28 — last reviewed against AAN, AANEM and NINDS guidance; internal links and schema verified.
- Review cadence: quarterly, or sooner if guidance changes.
How to cite this page
Clinical Neurology Specialists. “Evoked potentials Henderson.” Reviewed 2026-07-28. https://www.cnsnevada.com/diagnostic-testing/evoked-potential-studies/evoked-potentials-henderson/
References
- American Association of Neuromuscular & Electrodiagnostic Medicine — electrodiagnostic study standards and laboratory accreditation.
- Muscular Dystrophy Association — patient information on neuromuscular disorders.
- National Institute of Neurological Disorders and Stroke — the reference catalogue of nervous-system disorders.
This page is for general information about a Clinical Neurology Specialists office and is not medical advice, a diagnosis, or a treatment recommendation. It does not create a physician-patient relationship. Adults 18 and older. For an active stroke, a first-time or prolonged seizure, sudden severe headache, sudden weakness, sudden vision loss, or a head injury with loss of consciousness, call 911 or go to the nearest emergency department.