Extended High Frequency Thresholds and Their Relationship to Distortion Product Otoacoustic Emissions, Hearing Acuity, Age, Gender, Presence of Spontaneous Otoacoustic Emissions, and Side of Measurement  
[PERSON]  
1 Institute of Physiology and Pathology of Hearing, UI. [PERSON] 10, 02-042 Warsaw, Poland; [EMAIL_ADDRESS] (E.P. ); [EMAIL_ADDRESS] (M.P. ); [EMAIL_ADDRESS] (K.K. ); [EMAIL_ADDRESS] (H.S.) [PERSON]  
1 Institute of Physiology and Pathology of Hearing, UI. Mochnackiego 10, 02-042 Warsaw, Poland; [EMAIL_ADDRESS] (E.P. ); [EMAIL_ADDRESS] (M.P. ); [EMAIL_ADDRESS] (K.K. ); [EMAIL_ADDRESS] (H.S.) [PERSON]  
1 Institute of Physiology and Pathology of Hearing, UI. Mochnackiego 10, 02-042 Warsaw, Poland; [EMAIL_ADDRESS] (E.P. ); [EMAIL_ADDRESS] (M.P. ); [EMAIL_ADDRESS] (K.K. ); [EMAIL_ADDRESS] (H.S.) [PERSON]  
1 Institute of Physiology and Pathology of Hearing, UI. Mochnackiego 10, 02-042 Warsaw, Poland; [EMAIL_ADDRESS] (E.P. ); [EMAIL_ADDRESS] (M.P. ); [EMAIL_ADDRESS] (K.K. ); [EMAIL_ADDRESS] (H.S.) types. If hearing at low frequencies (i.e., \(\leq\)1 kHz) is of interest, it is better to test using tone-burst-evoked OAEs (e.g., [9,10]). In the present study, the main focus is on high frequency hearing. Thus, of all the various types of OAEs, DPOAEs are the preferred test technique. In this context, it is worth noting that subjects with better EHF thresholds tend to have higher DPOAEs at frequencies below 8 kHz [11]. In other words, DPOAEs can be used as indicators of preclinical changes in hearing [12,13]. Related studies have shown that in both adults and children, DPOAEs in the standard frequency (SF) range (up to 6 kHz) correlate with EHF HTs [14,15], i.e., the lower the threshold, the higher the amplitude of DPOAEs. On the other hand, some previous works indicate that DPOAEs correlate only with EHF thresholds and not with SF thresholds when HTs are within normal limits [16,17]. There is another study which has shown that DPOAEs in the SF range (up to 6 kHz) correlate with HTs in the SF and EHF ranges [18], but this needs to be contrasted with another, earlier study, which indicated that EHF hearing is not associated with DPOAE measures recorded below 4 kHz [19]. A large fraction of subjects will also have spontaneous OAEs (SOAEs), which are measurable without stimulation [20]. The prevalence of these ranges from about 35 to 80% depending on the experimental set-up [21, 22, 23]. However, in general, the presence of SOAEs is taken to be a mark of good overall hearing. Across many studies, ears with SOAEs have been shown to produce higher levels of TEOAEs and DPOAEs (e.g., [16,24, 25, 26]). However, when looking for an association with HTs, there are few studies and the results are mixed. Comparing ears with SOAEs to those without, one study found lower thresholds for hearing below 8 kHz [27], but another found no difference [16]. Interestingly, however, [PERSON] and colleagues did find a significant difference in the 8-16 kHz threshold between ears depending on whether they had SOAEs. Even more puzzling, [PERSON] and co-workers found no difference in EHF thresholds between ears with and without SOAEs, even though there were significant differences detected at 0.125, 0.25, and 0.5 kHz [28]. A relatively recent advance in clinical OAE equipment has provided the option to acquire responses in the EHF range (i.e., \(>\)8 kHz), reflecting early experimental work by [PERSON] and [PERSON] [29] and [PERSON] et al. [30] for DPOAEs and by [PERSON] et al. [31] for TEOAEs. The rationale for this study is that the relationship between EHF HTs and EHF DPOAEs has not been sufficiently researched. Considering the importance of better diagnosis, there are only a very small number of studies on this topic, and the results are inconclusive [16, 17, 18, 19]. Although the relation between EHF HTs and DPOAEs in the SF range has been reasonably well studied, the amount of data on EHF DPOAEs is much smaller.