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Otol Neurotol. 2014 Apr;35(4):719-24. doi: 10.1097/MAO.0000000000000242.

Sequential multipoint motion of the tympanic membrane measured by laser Doppler vibrometry: preliminary results for normal tympanic membrane.

Author information

1
*Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, and †Department of Information and Knowledge Engineering, Graduate School of Engineering, Tottori University, Tottori, Japan.

Abstract

BACKGROUND:

Numerous studies have reported sound-induced motion of the tympanic membrane (TM). To demonstrate sequential motion characteristics of the entire TM by noncontact laser Doppler vibrometry (LDV), we have investigated multipoint TM measurement.

MATERIALS AND METHODS:

A laser Doppler vibrometer was mounted on a surgical microscope. The velocity was measured at 33 points on the TM using noncontact LDV without any reflectors. Measurements were performed with tonal stimuli of 1, 3, and 6 kHz. Amplitudes were calculated from these measurements, and time-dependent changes in TM motion were described using a graphics application.

RESULTS:

TM motions were detected more clearly and stably at 1 and 3 kHz than at other frequencies. This is because the external auditory canal acted as a resonant tube near 3 kHz. TM motion displayed 1 peak at 1 kHz and 2 peaks at 3 kHz. Large amplitudes were detected in the posterosuperior quadrant (PSQ) at 1 kHz and in the PSQ and anteroinferior quadrant (AIQ) at 3 kHz. The entire TM showed synchronized movement centered on the PSQ at 1 kHz, with phase-shifting between PSQ and AIQ movement at 3 kHz. Amplitude was smaller at the umbo than at other parts. In contrast, amplitudes at high frequencies were too small and complicated to detect any obvious peaks.

CONCLUSION:

Sequential multipoint motion of the tympanic membrane showed that vibration characteristics of the TM differ according to the part and frequency.

PMID:
24317215
DOI:
10.1097/MAO.0000000000000242
[Indexed for MEDLINE]

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