Case PresentationCase Presentation

Beth BurlageBeth Burlage

HistoryHistory

• 75-year-old male• Reports constant dizziness and imbalance

• Problems initially began after a serious auto accident in 1998

• Immediately after the accident, the dizziness was present and over time became progressively worse

• Had a CT scan (imaging) and is scheduled for his first MRI following VNG

• 75-year-old male• Reports constant dizziness and imbalance

• Problems initially began after a serious auto accident in 1998

• Immediately after the accident, the dizziness was present and over time became progressively worse

• Had a CT scan (imaging) and is scheduled for his first MRI following VNG

AudiogramAudiogram

VNG testingVNG testing• VNG - video nystagmography

• Records eye movements such as nystagmus - a type of eye movement characterized by alternating slow phase movements in one direction quick phases in the other direction.

There are two types of nystagmus:

• Physiologic nystagmus- normal - slow phases are vestibulo-ocular reflex movements that stabilize vision during head movement, whereas the fast phases are re-setting movements.

• Pathologic nystagmus - abnormal-the slow phases may be due to a vestibular imbalance or due to failure in the eye position-holding mechanisms of the oculomotor system.

• “nystagmus production is a complex phenomenon that involves many neuronal centers and the changes in nystagmus characteristics are often of diagnostic value” Jacobsen, et. al. 2000

• VNG - video nystagmography

• Records eye movements such as nystagmus - a type of eye movement characterized by alternating slow phase movements in one direction quick phases in the other direction.

There are two types of nystagmus:

• Physiologic nystagmus- normal - slow phases are vestibulo-ocular reflex movements that stabilize vision during head movement, whereas the fast phases are re-setting movements.

• Pathologic nystagmus - abnormal-the slow phases may be due to a vestibular imbalance or due to failure in the eye position-holding mechanisms of the oculomotor system.

• “nystagmus production is a complex phenomenon that involves many neuronal centers and the changes in nystagmus characteristics are often of diagnostic value” Jacobsen, et. al. 2000

Pertinent FindingsPertinent Findings

• All eye-movement systems depend on the same cranial nerves and ocular muscles to effect the specific type of eye motion desired. The brain stem cranial nerve nuclei, cranial nerves, and extra-ocular muscles are the final common pathway for all eye movements

• Ocular motor tests include:• Gaze, Saccades, tracking, OKN

• Gaze testing - this portion of the test is one of various test conditions that assesses the vestibulo-ocular function. The patient is asked to focus on a light (without moving his/her head). The light remains stable in either a horizontal or vertical position and then rebounds to a center position.

• All eye-movement systems depend on the same cranial nerves and ocular muscles to effect the specific type of eye motion desired. The brain stem cranial nerve nuclei, cranial nerves, and extra-ocular muscles are the final common pathway for all eye movements

• Ocular motor tests include:• Gaze, Saccades, tracking, OKN

• Gaze testing - this portion of the test is one of various test conditions that assesses the vestibulo-ocular function. The patient is asked to focus on a light (without moving his/her head). The light remains stable in either a horizontal or vertical position and then rebounds to a center position.

Gaze TracingsGaze Tracings

• Right directed gaze shows right beating nystagmus, upon rebounding, the nystagmus is direction changing

• In the left directed condition, nystagmus is left beating and direction changing upon rebounding

• Bilateral horizontal gaze nystagmus

• Right directed gaze shows right beating nystagmus, upon rebounding, the nystagmus is direction changing

• In the left directed condition, nystagmus is left beating and direction changing upon rebounding

• Bilateral horizontal gaze nystagmus

Pertinent Findings, cont.

Pertinent Findings, cont.

• Saccade - vestibulo-ocular assessment. The patient is asked to follow the light with their eyes without moving their head as it randomly moves across a vertical plane

• Saccade - vestibulo-ocular assessment. The patient is asked to follow the light with their eyes without moving their head as it randomly moves across a vertical plane

Saccadic tracingSaccadic tracing

• The saccades display direction changing nystagmus beating in the direction of the light’s movement (ex. When the light bounces towards the left, nystagmus is left-beating)

• The saccades display direction changing nystagmus beating in the direction of the light’s movement (ex. When the light bounces towards the left, nystagmus is left-beating)

Pertinent findings, cont.

Pertinent findings, cont.

• Caloric stimulation- using air irrigation, the horizontal semi-circular canal is stimulated by temperature changes in the ear.

• Even those with normal vestibular function will present with nystagmus and sensations of dizziness during caloric testing

• Caloric stimulation- using air irrigation, the horizontal semi-circular canal is stimulated by temperature changes in the ear.

• Even those with normal vestibular function will present with nystagmus and sensations of dizziness during caloric testing

• Normal findings show that upon fixating their eyes on an object (in this case, a small light inside of the video goggles), the patient will be able to suppress the nystagmus.

• Normal findings show that upon fixating their eyes on an object (in this case, a small light inside of the video goggles), the patient will be able to suppress the nystagmus.

Caloric tracingsCaloric tracings

• Upon fixation, the patient not only was unable to suppress, the nystagmus actually became stronger

• It is noted that failure to fixate bilaterally is an implication of brainstem or cerebellar disease

• Upon fixation, the patient not only was unable to suppress, the nystagmus actually became stronger

• It is noted that failure to fixate bilaterally is an implication of brainstem or cerebellar disease

InterpretationInterpretation

• Results indicate a Central Nervous System (CNS) lesion

• CNS lesions can often be the result of drug intoxication, abnormal growths, or likely in this case, traumatic brain injury

• Results indicate a Central Nervous System (CNS) lesion

• CNS lesions can often be the result of drug intoxication, abnormal growths, or likely in this case, traumatic brain injury

ManagementManagement

• Refer to Neurology for MRI• After neurologic assessment and possible treatment, reassess central vestibular function

• Hearing loss - hearing aids? – VAMC policy is to provide hearing aid to those who express interest/need

• Refer to Neurology for MRI• After neurologic assessment and possible treatment, reassess central vestibular function

• Hearing loss - hearing aids? – VAMC policy is to provide hearing aid to those who express interest/need