Threshold shift validity by documenting sensorineural acuity level: a useful tool for masking

Abstract

<p class="abstract"><strong>Background:</strong> Masking dilemma is a condition prevalent whenever there is significant hearing loss in non-test ear and conductive hearing loss in test ear resulting into narrow or non-existent plateau width. Three feasible ways are divulged to circumvent this condition namely, Sensorineural acuity level testing, Fusion Inferred at threshold and use of insert type transducers. Different circumstances encountered when using insert type transducers and Fusion Inferred at threshold test has made it peril to use. Thus, administration of sensorineural acuity level test has been preferred. Sensorineural acuity level test involves computation of individual threshold shifts and its comparison with normal threshold shifts when a maximum level of bone conducted noise is presented at the centre of forehead via bone conduction vibrator. This research study aims to document normal threshold shifts and its validation in individual with bilateral symmetrical sensorineural hearing loss.</p><p class="abstract"><strong>Methods:</strong> A prospective study was carried out among 50 normal individuals and 50 patients with bilateral symmetrical sensorineural hearing loss. Pertinent measures were taken to ensure fulfilment of all-inclusive and exclusive criteria. In addition, air conduction and bone conduction threshold were computed using conventional methods followed by administration of sensorineural acuity level test. Necessary comparison was made among the threshold shifts. </p><p class="abstract"><strong>Results:</strong> Inferences drawn showed closer correlation between sensorineural acuity level threshold and bone conduction thresholds during puretone audiometry.</p><p class="abstract"><strong>Conclusions:</strong> Sensorineural acuity level test has shown to be effectual in both rehabilitation and medical interventions. Besides, imperative role of an audiologist can be recognized in its administration and elucidation for better prognostication.</p>

Are the Normative Values of Sensorineural Acuity Level (SAL) Test Affected by Head Circumferences of Subjects?

“…The SAL normative values obtained in the current study are in accordance with the previous findings reported by Awang et al [13] and Kapoor et al [23]. It is worth stating that both studies used the B81 bone vibrator to establish the SAL normative values among healthy Asian adults.…”

“…That is, it is problematic if the genuine BC thresholds are not established as the type of hearing loss could not be confirmed subsequently (leading to an incomplete hearing diagnosis). It is worth stating that overmasking is a common problem in the PTA testing and must be carefully addressed [12,13,23]. The SAL test is valuable in determining masked BC thresholds in cases of overmasking so that an accurate hearing diagnosis can be made.…”

The Normative Data for Sensorineural Acuity Level (SAL) Test among Young Adults: Comparisons Between B71 and B81 Bone Transducers

“…It is worth noting that the type of bone oscillator was not stated in the study by Jerger and Tillman [19]. On the other hand, in a study by Kapoor et al involving 50 normal-hearing Indian adults (n = 100 ears) aged 18 to 60 years old [33], the SAL normative data were measured using the Radioear B81 bone vibrator. The median SAL normative data were 40 dB at 250 Hz, 60 dB at 500 Hz, 60 dB at 1000 Hz, 55 dB at 2000 Hz, and 50 dB at 4000 Hz.…”