Chrissy Durrough Lugge
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The lack of a catch-up saccade during head impulse testing tells us that her vestibulo-ocular reflex is presumably intact and, therefore, she likely does not require adaptation exercises. In reality, there are some weeds that make this messier – but they are likely beyond the scope of the NCS. If the patient did not have so many signs of motion sensitivity and she reported symptoms only during head impulse testing but still did not have an overt retinal slip, I would consider implementing gaze stabilization exercises for the purposes of adaptation.
Additionally, if the patient doesn’t respond to physical therapy interventions, I might recommend more sophisticated testing. Some physical therapy clinics can do video head impulse tests (vHIT) that can detect covert catch-up saccades that would indicate an abnormal VOR that is not observable without equipment. Audiologists who complete full vestibular function test batteries can also do vHIT – and I might recommend complete vestibular function testing for this patient that would quantify how well the peripheral vestibular system is functioning and detect any asymmetries. Vestibular function testing is summarized in the vestibular lecture under “diagnostic and medical management”.
They would still be an AIS A without sacral sparing. They could actually have functional strength in their legs without any sacral sparing and still be an AIS A. In some cases, the ISNCSCI classification is not always consistent with functional ability.
Hi Sydney,
To be classified as an AIS C, this patient would need either (1) voluntary anal sphincter contraction or (2) sacral sensory sparing AND motor function MORE than 3 levels below the motor level.If this patient had sacral sensory sparing with his motor scores, he would be classified as an AIS B. His motor sparing is 3 levels below the motor level (C7), but not MORE than 3 levels. If he had sacral sensory sparing and motor function to C8, he would then be classified as AIS C.
On the second page of the ISNCSCI form, you can find these criteria in the footnote (marked with a **) in the middle column.
Hope this helps!
Chrissy
Hi Alex,
No need to apologize; these questions are why I’m here!
I’ll do my best to clear some of this up:
#8 – This researcher found that her new quality of life survey was not *actually* measuring quality of life. Quality of life is the abstract concept she was trying (and failing) to measure, so the survey lacks construct validity. Face validity is a fairly superficial and the least scientific measure of validity; it means that a test *looks like* it is measuring what it is supposed to measure. To determine face validity, we would ask an untrained person to read the survey and see what they think it is measuring. We don’t have any details about the new survey in question, so we cannot speak to what someone would think it is measuring and its face validity. Face validity is subjective – and there are times when we would actually desire low face validity (for example, a test for mental illness when an individual may be motivated to answer questions to avoid an undesirable diagnosis).
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#19 – Adaptation exercises are aimed at inducing neurorecovery by improving an abnormal vestibulo-ocular reflex. Adaptation exercises include gaze stabilization (VORx1 and VORx2) that induces an error signal (retinal slip). Those occasional errors drive neuroplasticity to improve our VOR gain (note: As with inducing neuroplasticity in other populations, a task that is too easy or too difficult with not drive change. Occasional errors are critical for learning, but constant errors shut down learning.). An individual with an abnormal vestibulo-ocular reflex would demonstrate an abnormal head impulse test and would report symptoms primarily with tasks that involve head turns.This patient is reporting dizziness with all movement, not isolated to head turns. She does not have a positive head impulse test and she only feels relief when she is still. This indicates general motion sensitivity rather than a diagnosis that would warrant vestibular adaptation exercises (like unilateral vestibular hypofunction).
Motion sensitivity is treated with habituation exercises. Habituation exercises are repeatedly exposing a person to the stimulus that creates symptoms with the goal of desensitization. I think about this as riding a spinning ride at an amusement park. The first time I ride the ride, I might feel very dizzy. If I ride it 10 times in a row, I won’t feel as dizzy from the 9th to 10th time as I do from 0-1 times.
In this case, we would select certain movements that cause dizziness. These can be selected through interviewing the patient and/or by administering a standardized measure like the Motion Sensitivity Quotient. We would select 3-5 specific movements and have the patient perform them repeatedly a couple times per day. Examples of movements often selected for treating motion sensitivity are rolling supine to sidelying, turning the head horizontally, and performing 180-degree turns.
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#37 – Great point! I’ve flagged this question to review in the off-season. The point of the question was to emphasize that the vestibulo-ocular reflex is primarily a peripheral function and impairments are consistent with peripheral vestibular dysfunction (like neuritis or labrynthitis) and the cerebellum is a central structure for which dysfunction would cause central vestibular dysfunction. VOR cancellation, smooth pursuits, and saccades are purely central functions. However, you are correct that there are some central influences to the VOR itself and cerebellar dysfunction could cause problems here. The *best* answer here is VOR because it is the only one that is not driven purely by central functions and I like some ambiguity because the NCS exam will ask you to pick the “best” option from multiple “good” ones, but I think the question could maybe use some tweaking.___
#72 – Postural instability is a cardinal sign of Parkinson’s disease, but it does not respond to dopamine replacement therapy. The other cardinal signs do respond to medications. Cognitive and autonomic symptoms are also unresponsive to medications. Therefore, dysarthria is the best choice.Chrissy
Hi Sydney,
All the practice exams for the NCS Advantage are linked on the course homepage. Once you are logged in to the website, click on “Dashboard” in the top right. Then, scroll down to the “Courses” section. You can select “Course Homepage” to see all the NCS Advantage content (including the practice exams) or “Practice Exams” for a more succinct page that only contains exams.
ChrissyThe first download under Supplementary Material at this link provides a full list of the exercises: https://www.neurology.org/doi/10.1212/WNL.0b013e3181c33adf#supplementary-materials
The whole body movements included arm and leg movements in standing and kneeling activities.
Variability in movements from trial to trial can be attributed to motor noise and exploration variability. Exploration variability are conscious attempts to modify movements to be more successful. Individuals are generally unaware of their motor noise. Individuals with cerebellar dysfunction have more motor noise than normal controls (due to ataxia/incoordination). Performance tends to decline with increasing motor noise.
Hi Karen,
Error-based learning requires feedback about error data to allow the learner to make corrections on a trial by trial basis. If you recall our motor learning module, error-based learning requires knowledge of performance and often includes concurrent feedback. In the clinic, this might look like using biofeedback about weight shifting on a forceplate to control a figure on a computer monitor. It could also be throwing Velcro balls a target where the learner can see how far their attempts land from the bullseye.Reinforcement learning involves only knowledge of results (success or failure) and terminal feedback that forces the learner to explore options to facilitate more successful outcomes. In the clinic, this might look like throwing a ball at a target and the learner only knowing whether they hit the target (success) or not (failure).
Closed loop reinforcement learning means that task difficulty is controlled based on recent performance. In the ball-throwing example, this might mean moving the target to make it easier or harder to hit based on the patient’s recent attempts.
Hi Alyson,
Spontaneous nystagmus may occur due to a central impairment (usually up or down beating) or due to a vestibular imbalance (peripheral).
In the case of vestibular imbalance, spontaneous nystagmus generally occurs in the acute stage (vestibular neuritis, after vestibular schwannoma resection, etc.) with the fast phase beating toward the intact ear and would be expected to gradually fade away.Gaze-evoked nystagmus is nystagmus that is only present for certain directions of gaze. Gaze-evoked nystagmus is considered normal with prolonged gaze holding or at end range of motion. Persistent gaze-evoked nystagmus for ocular displacement of 30 degrees or less are considered abnormal. Causes of abnormal gaze-evoked nystagmus include medications (especially sedatives and anti-convulsants), alcohol/recreational drugs, and brainstem/cerebellar disorders.
Screening for these types of nystagmus in the clinic is generally completed by observing eye movements at rest and during our oculomotor screen. I screen for gaze-evoked nystagmus by pausing at the end range of my assessment (not the patient’s maximal ocular excursion) in all directions during my smooth pursuit exam – keeping in mind that gaze-evoked nystagmus would be expected at maximal ocular excursion. Spontaneous nystagmus can also be observed with VNG.
Note that spontaneous and gaze-evoked nystagmus can also be congenital.
Chrissy
Good catch, Valerie! I clarified the question to indicate strength scores are within the available range of motion.
Hi Karen,
Yes, Uhthoff’s phenomenon is temporary (<24 hours) and is not indicative of a relapse or exacerbation. Interestingly, Uhthoff's phenomenon was once used as in the diagnosis of MS ("hot bath test") before MRI and CSF analysis were as advanced as they are now.I don't recommend spending time memorizing the names and administration routes and timelines for the medications. I think understanding that different medications are used for managing relapses versus disease-modifying pharmacologic therapies and that various routes of administration are used is sufficient. There's a chance something super specific could sneak onto the test, but this is unlikely and your time is likely better spent on bigger topics.
The 25FWT is part of the MS Functional Composite assessment (https://www.nationalmssociety.org/For-Professionals/Researchers/Resources-for-MS-Researchers/Research-Tools/Clinical-Study-Measures/Multiple-Sclerosis-Functional-Composite-(MSFC)). This is likely why physicians who see patients with MS tend to use the 25FWT in their exams.
Chrissy
This is from our Frequently Asked Questions page (https://rehabknowledge.com/frequently-asked-questions/):
Because we do not have access to the scoring algorithm for the ABPTS exams, we cannot reliably say how performance on our practice exams predicts performance on the NCS, OCS, and PCS exams. The average scores on our practice exams are listed below. Over 98% of our participants report passing their ABPTS exam. So, if you are scoring somewhere near the range of our average scores, you are likely on track for your exam.
NCS Advantage
First attempt: 60-70%
Subsequent attempts: 75-85%Hi Ashley,
A dry erase board should be provided for you to make notes during the exam. That has been the protocol every year. I couldn’t find confirmation of this on the ABPTS website (https://specialization.apta.org/become-a-specialist/exam-specialty-resources/exam-day), so it may be worth emailing them to confirm – spec-cert@apta.org.We have a quick reference page to help you know what to expect on test day, as well: https://rehabknowledge.com/ncs-advantage/test-day-guidelines/
Hope this helps!
Chrissy
