VHIT EFFECT OF AGE

This material is intended for clinicians and vestibular scientists. See also: bedside version -- HIT test

Timothy C. Hain, MD Page last modified: March 2, 2021

See also: vhit, vhit_norms, vhit_conflict, vhit_research, vhit_technical glitches, vhit_compensation.

Before beginning, it is important to realize that VHIT gains are "all over the place", and what we are looking at here are averages, not individual values. Individual variability greatly outweighs the small effects of age.

Effects of Age on VHIT -- not so much:

VHIT gain by age
Plot of the association VHIT gain vs head velocity according to age, using the GNO device( Figure 3 from Matino-Soler et al (2014)). There is a decline that occurs at high velocities, over the age of 61. Note that there are no error bars here.

 

Somewhat similarly but with many more subjects, the graph below plots VHIT average gain in 4227 dizzy patients.

VHIT gains at CDH

The average VHIT gain in decades 1-6 (in dizzy patients) ranges between 1.04 and .97. In decades 7 and 8, gain drops slightly (0.96, 0.92). This is very similar to the data above for entirely normal subjects. It is clear that there is no large age-effect on VHIT gain. Comparing the first 5 decades (about 1.0) to the age of 80, gain drops by only 8%. This is less than the 25-35% drop in the gain_TC product on rotatory chair testing, and of hugely less than the drop in VEMP amplitude. This probably reflects the effort of the CNS to use plasticity to maintain VOR gain. It suggests that VHIT gain is a poor parameter to follow aging of the vestibular apparatus.

There are only a few subjects in the 9th decade and this data cannot be trusted. There are many low-gain "outliers", which are largely patients with vestibular lesions. The high-gain outliers are technical artifacts of this device and are legitamate outliers (see the VHIT norms page). This plot was produced using "R". The R code that generated the above plot is found here:

We will not discuss here the "normative" study of McGarvie et al, as it was done using a prototype device (2015). As norms are device dependent (see here), it makes no sense to depend on data from a prototype,


References

  1. Matino-Soler et al. Normative data on angular vestibulo-ocular responses in the Yaw axis measured using the video head impulse test. Otology and Neurotology 36:466-471, 2014
  2. McGarvie et al. The video head impulse (vHIT) of semicircular canal function - age-dependent normative values of VOR gain in healthy subjects. Frontiers in Neurology, 2015 (Note this an open access journal).