Contralateral suppression of TEOAE in diabetic children. Effects of 1.0 kHz and 2.0 kHz pure tone stimulation--preliminary study.
The medial efferent system and its regulating outer hair cell function have not been previously studied in diabetic children. In this study, the group comprised 32 diabetic children, aged 6.0-16.0 years, with diabetes lasting 2.0-9.0 years, with normal tonal and impedance audiometry. A control group consisted of 30 healthy children with similar age and sex distribution. Contralateral stimulation (CS) was performed using 1.0 and 2.0 kHz pure tones on the level of 30 and 50 dB SL. Effects of CS on transient evoked otoacoustic emissions (TEOAE) elicited by click of a level equal to 70 and 60 dB SPL were investigated. Analysis included assessment of TEOAE amplitude and 0.8 kHz frequency bandwidth (0.8-FBW) amplitudes (signal/noise) centred at 1.0; 2.0; 3.0; 4.0; 5.0 kHz. TEOAE-RA recorded for stimulus 80, 70 and 60 dB SPL without CS were decreasing: average values respectively 7.3, 4.7 and 3.9 dB SPL. In the group of diabetic children TEOAE amplitudes, recorded for different click levels without CS, were similar to these recorded in healthy children. It suggested that normal function of the cochlea was preserved, mostly outer hair cells. However, the obtained effects of CS, in comparison with healthy children, were weaker and not so regular. Statistical analysis revealed that the reduction of TEOAE amplitudes for adequate 0.8-FBW in the control group was significantly higher, for both 1.0 kHz and 2.0 kHz CPTs of 30 dB SL and 50dB SL, in comparison with diabetic children. It is concluded that the suppressive effect on OAE in diabetic children is rather weak and seems to be associated with pathological changes in medial olivo-cochlear myelinated fibres.
Namyslowski
G
G
2nd ENT Department, Silesian Medical Academy, Zabrze, Poland. hno@friko.onet.pl
Morawski
K
K
Kossowska
I
I
Lisowska
G
G
Koehler
B
B
Jarosz-Chobot
P
P
D000293:Adolescent; D001301:Audiometry, Pure-Tone / Q000379:methods*; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D005260:Female; D006311:Hearing Disorders / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D006801:Humans; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D012720:Severity of Illness Index