Quantitative estimation of brain stiffness measured using a tactile biosensor in animal models.
OBJECTIVE
The purpose of this experimental study was to evaluate the clinical application of a tool equipped to measure the consistency of soft tissue.


RESULTS
We have measured three kinds of soft tissues with brain-like softness. Also, we evaluated the stiffness of an animal brain with intracranial hypertension. Next, we attempted to measure the mechanical properties of three materials using a tactile sensor. This sensor measures three parameters: depth, pressure, and the change in resonance frequency. The change in resonance frequency correlated linearly on a semi-log scale with the stiffness of the gelatin. Next, we measured brain stiffness using an epidural balloon expansion model in 28 rats. The rats were divided into five groups based upon the volume of saline solution infused into the balloon. Rat brain stiffness was measured using the tactile sensor. We then analyzed the relationship between change in resonance frequency in tactile sensor and the I-IV latency in brainstem evoked potentials under increased balloon volume. The value of change in resonance frequency decreased with the increment of volume (Spearman's test: R = 0.777).


CONCLUSIONS
The tactile sensor is an appropriate tool for quantitatively measuring the palpability of soft materials, which probably includes the brain and spinal cord.
Department of Neurosurgery, Shimane University School of Medicine, Izumo, Japan. yy1971@med.shimane-u.ac.jp
Yoshiaki
Y
Yamamoto
Kouzo
K
Moritake
Hidemasa
H
Nagai
Masaaki
M
Sato
D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods*; D001921:Brain / Q000502:physiology*; D004548:Elasticity; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013223:Statistics as Topic; D014110:Touch / Q000502:physiology*; D014732:Vibration