Investigation of Presentation Levels for Optimal Use of NU-6 Ordered by Difficulty Version II Word Lists

The current work sought to identify the optimal presentation levels for the NU-6 ordered-by-difficulty (OBD) abbreviated word lists. An optimal presentation level would yield a listener's highest word recognition score (WRS; known as phonetically balanced [PB] max) and allow the use of a shortened test protocol. A protocol based on the dB sensation level (dB SL) at 2000 Hz was used as a starting point. It is not known if these two commonly used time-saving approaches can be used in combination to obtain optimal results.

WRSs were obtained at multiple levels. The initial level was based on the hearing threshold at 2000 Hz and was either increased or decreased. For listeners with hearing loss, uncomfortable listening (UCL) levels were measured, and a word list was presented 5 dB below the UCL. Thirty-four adults with (25) and without (9) hearing loss, who were recruited via flyers and direct contact, participated in this study. A descriptive analysis was conducted to identify the level needed to obtain PB max using OBD word lists with the least number of words.

In most cases, the initial presentation level did not yield PB max and required more than 10 words.

It is recommended that the presentation level for NU-6 OBD word lists be at least 30-40 dB SL relative to the hearing threshold at 2000 Hz with a minimum presentation level of 35 dB HL. If this is not feasible, the presentation of these words at UCL-5 is recommended.