User:Derica.parathundil/sandbox

= Videonystagmography = Videonystagmography (VNG) is a type of testing used to assess vestibular and central nervous system function through the use of eye movement tracking, specifically evaluating nystagmus. The older version of technology used to performed these tests, known as electronystagmography (ENG), leverages electrophysiological signals. There is a battery of tests which can be performed using this technology and testing, typically performed by an audiologist. These tests can be diagnostic in nature or used to monitor rehabilitation. The testing typically takes place in a dark or dimmed room with the patient laying or sitting, depending on the test, on a table or chair that can lean back to a flat position. The patient wears goggles containing a camera that tracks the pupils using infrared imaging; the video eye-tracking system records and sends pupil movement tracings to a computer typically with VNG analysis software. The goggles may also have a cover in order to deny vision for some tests while still recording eye movement. There may be some kind of screen or light bar used to present visual stimuli, though providers may use other kinds of visual stimuli for portions of the testing. VNG can determine whether dizziness is caused by inner ear disease, particularly benign paroxysmal positional vertigo (BPPV), as opposed to some other cause such as low blood pressure or anxiety.

Gaze
Gaze testing is performed to assess for spontaneous nystagmus, meaning a nystagmus present in the absence of. visual or vestibular stimulation. The initial position is typically looking ahead, then up, down, left, and right and held for a short period of time. For a video of how the testing is done, see: https://www.youtube.com/watch?v=eVU_C1S25Bo. Gaze is typically assessed with vision and vision denied (the goggles are covered to take away any visual input).

Smooth pursuit/Tracking
Smooth pursuit testing has the patient follow a visual target from left to right or up to down. For a video of how this testing is done and what results look like, see: https://www.youtube.com/watch?v=rIcY_AdfYAk. Aspects analyzed are velocity gain, asymmetry, and phase angle.

Saccades
Saccades evaluate voluntary saccadic movement, which are quick eye movements to a target. A dot or visual target appears at random points along the screen, though only along the horizontal axis is common. The patient is instructed to not try to guess where the target will be. This test measures latency, velocity, and accuracy. For a video of the testing and results collected, see: https://www.youtube.com/watch?v=BqDMuze0XZ8.

Optokinetic (OPK) test
Optokinetic testing assesses a response that occurs when trying to stabilize focus on a target while the visual field itself is moving (due to the person's head moving) ; an example of this response is when focusing on passing objects out the window while seated on a moving train, bus, or car. This test assesses velocity gain and asymmetry. For a video example of test stimuli and results, see: https://www.youtube.com/watch?v=D9dP02kd1Qk.

Positional Testing
These tests are performed with vision denied. If abnormalities are present, they may be repeated with vision allowed. For these tests, the patient is put into various positions, but no movement is occurring during the testing. Positions include sitting with the head straight ahead or turned, laying supine with the head straight ahead or turned, laying with the entire body and head facing the left or right, and the caloric position.

Dix-Hallpike
In McCaslin ch. 5

Supine Roll
Also known as the Pagnini-Lempert or Pagini-McClure Roll Test). In McCaslin Ch. 5

Supine Head Roll
In McCaslin ch. 5

Bow and Lean
In McCaslin Ch. 5

= Ototoxicity =

Signs and symptoms
Ototoxicity results in cochlear and/or vestibular dysfunction which can manifest as sensorineural hearing loss, tinnitus, hyperacusis, dizziness, vertigo, or imbalance. Presentation of symptoms vary in singularity, onset, severity and reversibility.

Hearing loss
Ototoxicity-induced hearing loss typically impacts the high frequency range, affecting above 8000 Hz prior to impacting frequencies below. There is not global consensus on measuring severity of ototoxicity-induced hearing loss as there are many criteria available to define and measure ototoxicity-induced hearing loss. Guidelines and criteria differ between children and adults.

Ototoxicity grades (Hearing Loss)
There are at least 13 classifications for ototoxicity. Examples of ototoxicity grades for hearing loss are the National Cancer Institute's Common Terminology Criteria for Adverse Events (CTCAE), Brock's Hearing Loss Grades, Tune grading system, and Chang grading system.

National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) (as described in the American Academy of Audiology Ototoxicity Monitoring Guidelines from 2009) :


 * Grade 1: Threshold shift or loss of 15-25 dB relative to baseline, averaged at two or more contiguous frequencies in at least one ear
 * Grade 2: Threshold shift or loss of >25-90 dB, averaged at two contiguous test frequencies in at least one ear
 * Grade 3: Hearing loss sufficient to indicate aural rehabilitation such as hearing aids and/or speech-language services
 * Grade 4: Indications of cochlear implant candidacy

Brock's Hearing Loss Grades (as described in the American Academy of Audiology Ototoxicity Monitoring Guidelines from 2009) :


 * Grade 0: Hearing thresholds <40 dB at all frequencies
 * Grade 1: Thresholds 40 dB or greater at 8000 Hz
 * Grade 2: Thresholds 40 dB or greater at 4000-8000 Hz
 * Grade 3: Thresholds 40 dB or greater at 2000-8000 Hz
 * Grade 4: Thresholds 40 dB or greater at 1000-8000 Hz

Chang grading system (as reported in Ganesan et al., 2018) :


 * 0: ≤ 20 dB at 1, 2, and 4 kHz
 * 1a: ≥ 40 dB at any frequency 6 to 12 kHz
 * 1b: > 20 and < 40 dB at 4 kHz
 * 2a: ≥ 40 dB at 4 kHz and above
 * 2b: > 20 and < 40 dB at any frequency below 4 kHz
 * 3: ≥ 40 dB at 2 or 3 kHz and above
 * 4: ≥ 40 dB at 1 kHz and above

Tune grading system (as reported in Ganesan et al., 2018) :


 * 0: No hearing loss
 * 1a: Threshold shift of ≥ 10 dB at 8, 10, and 12.5 kHz
 * 1b: Threshold shift of ≥ 10 dB at 1, 2, and 4 kHz
 * 2a: Threshold shift of ≥ 20 dB at 8, 10, and 12.5 kHz
 * 2b: Threshold shift of ≥ 20 dB at 1, 2, and 4 kHz
 * 3: ≥ 35 dB HL at 1, 2, and 4 kHz
 * 4: ≥ 70 dB HL at 1, 2, and 4 kHz

Hyperacusis
Hyperacusis is increased sensitivity to intensity (perceived as loudness) to what is typically deemed as normal/tolerable loudness.

Vestibular symptoms
Vestibular symptoms from ototoxicity, which would specifically be vestibulotoxicity, can include general dizziness, vertigo, imbalance, and oscillopsia.

Auditory testing
Auditory testing involved in ototoxicity monitoring/management (OtoM) is typically general audiological evaluation, high frequency audiometry (HFA), and otoacoustic emissions (OAEs). High frequency audiometry evaluates hearing thresholds beyond 8000 Hz, which is the typical cut-off for conventional audiometry. It is recommended a baseline evaluation be performed prior to treatment beginning.

The American Speech-Language-Hearing Association (ASHA) released guidelines in 1994. There are details on the different monitoring procedures on timelines depending on age and responsiveness.

The American Academy of Audiology (AAA) released guidelines in 2009. There are details on the kinds of tests which can be used.

The Health Professions Council of South Africa (HPSCA) released guidelines in 2018.

Significant change criteria
There are several guidelines on what constitutes a significant change in hearing which can indicate further action must be taken, whether that be to implement aural rehabilitation or adjust the source of ototoxic exposure (eg. chemotherapy). With pure tone audiometry, ASHA considers a significant change to have occurred if there is a :

If using distortion product ototoacoustic emissions (DPOAEs), a significant shift is observed if there is a reduction in amplitude by 6 dB or more than the baseline within the sensitive range of ototoxicity.
 * ≥ 20 dB decrease in pure tone thresholds at any test frequency OR
 * ≥ 10 dB decrease at two adjacent frequencies OR
 * no response at three consecutive test frequencies where responses were previously obtained

Vestibular testing
Vestibular tests for vestibulotoxicity specifically can include caloric testing, rotational testing, vestibular evoked myogenic potentials (VEMPs), and computerized dynamic posturography (CDP); however, there are no globally accepted guidelines for monitoring/management of vestibular function during or following ototoxic treatments.