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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).

#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.

#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.