RESEARCH PROJECTS
Timothy C. Hain, MD 
Page last modified:
January 5, 2008
Current Research
There are many clinical research projects currently being undertaken by Dr. Hain with many collaborators. Here is a selection of ones that are ongoing.
Sled project:
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| Linear Sled at NUPT |
With the support of NIH, we built a bobsled like device. It is very powerful and uses a magnetic drive to accelerate itself almost instantaneously at 2 gravities. A study, in collaboration with Emily Keshner, Ph.D, is presently underway in which we are measuring head stability in normal subjects, patients with bilateral vestibular loss, and patients with cerebellar disorders.
VEMP projects:
We are presently pursuing a large number of projects using the VEMP (vestibular evoked myogenic potential) protocol. This is a simple method of eliciting vestibulospinal reflexes
Recent projects have included assessment bone VEMP's, as well as arm and leg VEMPs. This methodology provides a very straightforward method of determining the degree to which the inner ear controls balance reactions in the body.
BPPV
Benign paroxysmal positional vertigo (BPPV) is the single most common cause of dizziness. It can be effectively treated by physical therapy.
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| Pedometer used to count steps in patients with BPPV. |
In a recent student synthesis project, we looked to see whether BPPV affects mobility, by assessing steps/day before and after successful treatment of BPPV.
This section has annotations and key illustrations from selected papers published since 1984.
Gaze-holding
- Robinson DA, Zee DS, Hain TC, Holmes AM, Rosenberg LF: Alexander's
law -- its behavior and origin in the human vestibulo-ocular reflex. Ann.
Neurology., 16:714-722, 1984. Nystagmus follows Alexander's law when it increases
when looking in the direction of the fast phase, and decreases or reverses
when looking in the direction of the slow phase. In this paper a feasible
explanation for Alexander's law is proposed for situations where there is
a vestibular imbalance-- summation of gaze-evoked nystagmus and vestibular
nystagmus. Alexander's law is clearly shown to be present in normal subjects
undergoing caloric irrigation.
- Zee DS, Hain TC, Carl JR: Abduction
nystagmus in internuclear ophthalmoplegia. Annals. Neurology., 21:383-388,
1987. The abducting nystagmus in INO appears in this patient to be under adaptive
control.
Saccades
- Kapoula ZA, Robinson DA, Hain TC: Motion
of the eye immediately after a saccade. Experimental. Brain Research.,
61:386-394, 1986. The eye movements of several normal subjects were recorded
with scleral eye coils, which is a highly accurate contact lens type device.
Saccades (rapid eye movements) frequently terminate with a small overshoot
combined with a rapid drift backwards. This is unlikely to have any functional
significance but is part of the spectrum of normal behavior..
- Hain TC, Zee DS, Mordes M: .Blink-induced saccadic
oscillations 19:299-301, 1986. Annals Neurology. For a summary of this
case of a cerebellar disorder with blink induced ocular flutter click on the
link above.
- Lasker AG, Zee DS, Hain TC, Folstein S: Saccadic
eye movements in Huntington's Disease: Initiation defects and distractibility.
Neurology, 37: 364-370, 1987. A paradigm was used in which subjects were asked
to look in the opposite direction of a target (the so-called "anti-saccade"
task). Huntington's disease patients have trouble doing this.
- Kapoula Z, Hain TC, Zee DS, Robinson DA: Adaptive
changes in post-saccadic drift induced by patching one eye. Vision Research,
27:1299-1307, 1987. Normal subjects were recorded with scleral eye coils before
and after 5 days of wearing a patch over one eye. Post-saccadic drift was
optomized for the viewing eye.
- Lasker AG, Zee DS, Hain TC, Folstein SF, Singer H: Saccades
in Huntingtons disease: Slowing and dysmetria. Neurology, 38:427-431,
1988. This was a scleral eye coil recording of patients with Huntingtons disease.
- Ashe J, Hain TC, Zee DS: Microsaccadic
oscillation -- a new clinical syndrome. Brain, 114, 461-472, 1991. A collection
of patients with tiny oscillations of their eyes, recorded with the scleral
eye coil..
Otoliths
- Hain TC: A model of the nystagmus induced by
off-vertical axis rotation Biological Cybernetics, 54:337-350, 1986. For
a summary of this modeling paper related to "barbeque" nystagmus
click on the local link above.
- Fetter M, Hain TC, Zee DS: Influence
of eye and head position on the vestibulo-ocular reflex. Experimental.
Brain Research., 64:208-216, 1986. The gain of eye movements in space in normal
subjects do what one would expect they would do, which implies the existence
of a neural mechanism that calibrates the vectorial properties of eye movements
in the orbit.
- Hain TC, Zee DS, Maria B: Tilt-suppression
of the vestibulo-ocular reflex in patients with cerebellar lesions. Acta
Otolaryngology. (Stockh), 105:13-20, 1988. This was largely a study of patients
with medulloblastomas, which is a tumor of the cerebellum which arises in
the cerebellar nodulus. These patients were different than normal subjects
in that they did not suppress their nystagmus when their head was tilted into
a pitched position. This likely reflects loss of otolithic modulation of velocity
storage through the cerebellar nodulus.
- Hain TC, Buettner UE: Static
roll and the vestibulo-ocular reflex (VOR). Experimental Brain Research.
82:463-471, 1990. This paper explored the time constant of the VOR with the
head tilted using the scleral eye coil method. The VOR time constant in different
planes clearly is reduced differentially by tilt away from vertical. This
causes a curvature of the VOR vector over time, which is documented and simulated.
Vestibular and oculomotor testing
Head-shaking Nystagmus
- Hain TC, Fetter M, Zee DS: Head-shaking
nystagmus in unilateral peripheral vestibular lesions. American J. Otolaryngology.,
8:36-47, 1987. This is one of several papers and chapters on head-shaking
nystagmus (HSN). This paper studied individuals with very well documented
unilateral vestibular lesions and showed that they all had HSN directed with
slow-phases toward the lesion. HSN appears to be related to a combination
of the degree of unilateral loss and the amount of remaining velocity storage.
Because velocity storage appears to be somewhat variable, HSN is not a very
good method of determining whether or not there is a unilateral vestibular
lesion.
- Wei D, Hain TC, Proctor L: Head-shaking
nystagmus: associations with canal paresis and hearing loss. Acta Otology.
108: 362-367, 1989. The second paper on HSN. HSN in about 100 patients with
dizziness who had caloric testing was not strongly tied to caloric canal paresis.
Some of this is likely related to noise in both techniques, and some to variability
in the population.
- Furman J, Hain TC, Paige G: Central
adaptation model of the vestibulo-ocular and optokinetic systems. Biological.
Cybernetics., 61:255-264, 1989. In this theoretical paper a control systems
model was developed to explain PAN (periodic alternating nystagmus). An "internal
model" was proposed which replaced behavior in the afferents with arbitrary
behavior determined centrally. The general idea that internal models are used
to replace sensor dynamics with centrally determined dynamics is the most
important portion of this paper.
OKAN
- Tijssen M, Straathof C, Hain TC, Zee DS: Optokinetic
afternystagmus in humans: normal values of amplitude, time constant and asymmetry.
Annals Otology, Rhinolology, Laryngology, 98:741-746, 1989. Normal values
for OKAN in 30 subjects are reported. OKAN is weak in normal subjects, being
strongest in young women.
- Hain TC, Zee DS: Abolition
of optokinetic afternystagmus by aminoglycoside ototoxicity. Annals Otology.
100:580-583, 1991. OKAN is lost after significant aminoglycoside toxicity.
- Hain TC, Patel G: Slow-cumulative
Eye Position to Quantify Optokinetic Afternystagmus. Annals Otology. 101:255-260,
1992. The SCEP is a very reasonable method of quantifying OKAN because it
is noise tolerant.
- Hain TC, Herdman SJ, Holliday MS, Mattox D, Zee DS, Byskosh AT: The
localizing value of optokinetic afternystagmus. Annals ORL, 806-811, 1994.
OKAN is asymmetrical after unilateral vestibular lesions, but because of variability
and generally reduced responses in human subjects, it is not a very powerful
method.
- Fletcher WA, Hain TC, Zee DS: Optokinetic
nystagmus and afternystagmus in human beings: relationship to nonlinear processing
of information about retinal slip. Experimental Brain Research, 1990.
Essentially a sensitivity analysis relating OKAN to full field velocity.
Clinical situations
- Young NM, Mets M, Hain TC: Early
Diagnosis of Usher Syndrome in Infants and Children. Am. J. Otology, 17:1,
30-34, 1996. Some patients with Usher syndrome have bilateral vestibular loss.
- Levin S, Luebke A, Hain TC, Zee DS, Robinson DA, Holzman PS: Smooth
pursuit eye movements in schizophrenics: quantitative measurements with the
search-coil technique. J. Psych. Research, 22:195-206, 1988. 10 patients
with well documented schizophrenia were recorded using the scleral eye coil
technique. Pursuit was moderately reduced in this group. To put this into
perspective, pursuit is also moderately reduced by living to be 55.
- Hain TC, Luebke A: Phoria
adaptation in patients with cerebellar lesions. Investigative Ophthalmology.
1990. Patients with cerebellar lesions have good phoria adaptation suggesting
that phoria adaptation is not mediated through the cerebellum (which is surprising).
- Tusa RJ, Kaplan PW, Hain TC, Naidu S: Ipsiversive
eye deviation and epileptic nystagmus. Neurology. 1990. A case report
of epileptic nystagmus.
- Hain TC, Hanna P, Rheinberger M. Mal de Debarquement.
Archives of Oto-HNS, 7/1999. Click HERE for more details.
Perilymph Fistula
Head and body motor control
- Herdman SJ, Sandusky AL, Hain TC, Zee DS, Tusa RJ: Characteristics
of postural stability in patients with gentamicin toxicity. J. Vestibular
Research. 4:71-80, 1994. In this study using moving platform posturography
it was shown that balance is impaired after significant loss of vestibular
input. This is not surprising.
- Rogers MW, Hain TC, Hanke TA, Janssen I: Effects
of stimulus parameters and inertial load on the incidence of protective stepping
responses in healthy human subjects. Arch Phys Med Rehabil 77:363-368,
1996.
- Peng GCY, Hain TC, Peterson BW: A
dynamical model for reflex activated head movements in the horizontal plane.
Biological Cybernetics, 75, 309-319, 1996. Model
of Head Motor Control (yaw), 1996. Click on the link above for more details.
- Peng CGY, Hain TC, Peterson BW. Predictions of vestibulo-collic (VCR) and
cervico-collic (CCR) reflex contributions to head stability during trunk perturbations
in the horizontal plane (accepted by Transactions in BME, 11/1998, to be published
in 10/1999)
- Keshner EA, Hain TC, Chen KJ. Predicting control mechanisms for human head
stabilization by altering the passive mechanics. Accepted J. Vest. Research
7/1999.
Rehabilitation of Vestibular Problems
Voice motor control
- Voice F0 Responses to manipulations in pitch feedback, Burnett TA, Freedland
MB, Larson CR, Hain TC, J. Acoustical Soc America, 103, 3153-3161, 1998
- Instructing subjects to make a voluntary response reveals the presence
of two components to the audio-vocal reflex. Hain TC, Burnett TA, Kiran S,
Larson CR Experimental Brain Research, 8/18/1999
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© Copyright
May 11, 2008
, Timothy C. Hain, M.D.
All rights reserved.
Last saved on
May 11, 2008
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