Slide 7 demonstrates that labyrinth deficits
have a major impact on balance in difficult balancing conditions, and
less in pre-programmed automotive motion. Slide 8 explains that the
extremely fast image stabilisation during head motion requires an intact
vestibular system (latency 8 ms) and cannot be substituted by the slow
visual system (latency 75 ms). In patients with a defective labyrinth,
image (and gaze) stabilisation is permanently impaired for fast head
impulses towards the affected side (slide 9). In case of bilateral
vestibular deficits, oscillopsia occurs as is simulated in slide 10. A
vestibular deficit therefore often leads to a permanently reduced
dynamic visual acuity and complaints about vision.
It is important to realise that vertigo and imbalance can indeed be leading
symptoms to set up a good differential diagnosis (slide 12 with a reference
and recommendation to a practical small clinical textbook). However, often
not vertigo but various other sustained complaints (slide 6) will be
associated to a centrally compensated vestibular deficit, and explaining
this relationship is crucial to allow patients to cope with their
impairments (slide 24).
The bedside examination is demonstrated on the video included in the slide
presentation (slide 14-16). In slide 17-22 some major rules are indicated
to interpret spontaneous and positioning nystagmus. All slides and video's
can be used freely for teaching purposes.
Download here the powerpoint presentation. If the movies
don't play inside the ppt, you can download them to your own
computer.
Click here to view the instruction movies: