Evaluation of Quantitative Measurement Techniques for Head Tremor With Thalamic Deep Brain Stimulation.
BACKGROUND
Ventralis intermedius thalamic deep brain stimulation (VIM DBS) has shown to be safe and effective for medically refractory essential tremor (ET). We evaluate the use of quantitative tremor measurement methods for head tremor in ET using a "smart" hat and a smartphone application.


METHODS
We enrolled 13 ET patients who previously underwent VIM DBS. Head and arm tremor was measured ON and OFF stimulation using the clinical gold standard Fahn-Tolosa-Marin Tremor Rating Scale (TRS). Results were then compared to two quantitative measurement techniques: Lift Pulse (smartphone application) and modified Nizet (adapted laser point measurement from Nizet et al.). Spearman's rank correlation was used to compare tremor severity and improvement on stimulation using TRS and quantitative methods to measure tremor.


RESULTS
Lift Pulse tremor severity measurement significantly correlated with TRS for head (ρ = 0.53, p < 0.01) and arm tremor (ρ = 0.49, p < 0.01). Modified Nizet tremor severity measurement significantly correlated with TRS for head (ρ = 0.83, p < 0.001) and arm tremor (ρ = 0.50, p < 0.01). Inter-method correlation for head tremor severity was significant (ρ = 0.45, p < 0.05). Lift Pulse tremor improvement measurement significantly correlated with TRS for arm tremor (ρ = 0.56, p < 0.05). Modified Nizet tremor improvement measurement significantly correlated with TRS for head tremor (ρ = 0.53, p < 0.01).


CONCLUSIONS
Our results show that Lift Pulse and modified Nizet are both effective techniques to quantitatively measure head and arm tremor severity. We also show the utility of a "smart" hat to measure head tremor. Modified Nizet technique is more effective for measuring head tremor, while Lift Pulse is an effective measure of tremor severity, especially arm tremor improvement.
Department of Neurosurgery, Albany Medical Center, Albany, NY, USA.
Arun
A
Chockalingam
Department of Neurosurgery, Albany Medical Center, Albany, NY, USA.
Hans
H
Boggs
Department of Neurosurgery, Albany Medical Center, Albany, NY, USA.|Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, USA.
Julia
J
Prusik
Department of Neurology, Albany Medical Center, Albany, NY, USA.
Adolfo
A
Ramirez-Zamora
Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, USA.
Paul
P
Feustel
Department of Neurosurgery, Albany Medical Center, Albany, NY, USA.
Abigail
A
Belasen
Department of Neurosurgery, Albany Medical Center, Albany, NY, USA.
Youngwon
Y
Youn
Department of Neurosurgery, Albany Medical Center, Albany, NY, USA.
Chris
C
Fama
Department of Neurosurgery, Albany Medical Center, Albany, NY, USA.
Jessica
J
Haller
Department of Neurosurgery, Albany Medical Center, Albany, NY, USA.|Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, USA.
Julie
J
Pilitsis
D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods / Q000592:standards*; D020329:Essential Tremor / Q000175:diagnosis* / Q000601:surgery*; D005260:Female; D006257:Head; D006801:Humans; D008297:Male; D008875:Middle Aged; D000068997:Smartphone / Q000592:standards* / Q000706:statistics & numerical data; D016896:Treatment Outcome; D020651:Ventral Thalamic Nuclei / Q000601:surgery*
Deep brain stimulation; essential tremor; head tremor; quantitative measurement; ventralis intermedius thalamus