Word Recognition Test

Am I Doing it Right? Word Recognition Test Edition

02/13/24

Word recognition testing evaluates a patient's ability to identify one-syllable words presented above their hearing threshold, providing a Word Recognition Score (WRS).

Word recognition testing is a routine part of a comprehensive hearing assessment and in an ENT practice, the WRS can be an indication of a more serious problem that needs further testing. Unfortunately, the common way WRS is measured may give inaccurate results. Let's talk about why that is.

One of the key variables to consider when performing word recognition testing is at what level to present the words. A common practice is setting the loudness of the words at 30 to 40 dB above the patient's Speech Reception Threshold (SRT), known as "SRT + 30 or +40 dB." Some also set the level to the patient's subjective "Most Comfortable Level" (MCL).

Clinicians often use one of these methods, assuming it ensures optimal performance. However, some research suggests that utilizing this method may not capture the maximum performance (PBmax) for those with hearing loss.

Consequently, this approach does not necessarily guarantee the most accurate WRS measurement. This fact prompts the question: Does this traditional method align with best practices and evidence-based approaches? Let's explore this further.

Audibility significantly impacts word recognition scores. Using only the SRT +30 dB or +40 dB method or MCL may not be the best strategy, as the audiogram configuration can affect whether words are presented at an effective level. Studies suggest that raising the presentation level could enhance WRS in some instances.

Since the SRT +30 dB or 40 dB method or MCL does not offer the best results, let's explore two methods supported by current research.

In a 2009 study, Guthrie and Mackersie compared various presentation levels to find the one that maximized word recognition in people with different hearing loss patterns. The Uncomfortable Loudness Level – 5 dB (UCL-5dB) method and the 2KHz Sensation Level method were found to have the highest average scores. Let's look at each of these methods separately.

The Uncomfortable Loudness Level (UCL) refers to the intensity level at which sounds become uncomfortably loud for an individual. In the UCL-5 dB method, the presentation level for word recognition testing is set to 5 decibels below the measured UCL.

This method aims to find the test subject's most comfortable and effective presentation level. While UCL-5 may be louder than the patient prefers, setting the presentation level slightly below the uncomfortable loudness threshold ensures that the speech stimuli are audible without causing discomfort. Patients with mild to moderate and moderately severe hearing loss obtained their best WRS at this level.

The 2KHz Sensation Level method for WRS testing involves determining the presentation level for speech stimuli based on the individual's hearing threshold at 2,000 Hertz (2KHz). Once determined, the words are presented at a variable Sensation Level (SL) relative to the patient's hearing threshold at 2KHz. In this case, SL is the difference between the hearing threshold at 2KHz and the loudness level of the words for the word recognition test.

The 2KHz Sensation Level (SL) method is convenient for busy clinics as it avoids the need to measure the UCL. This method involves using variable SL values determined in the following way:

  • 2KHz threshold <50dB HL: 25dB SL
  • 2KHz threshold 50-55dB HL: 20dB SL
  • 2KHz threshold 60-65dB HL: 15dB SL
  • 2KHz threshold 70-75dB HL: 10dB SL


This method tailors the presentation level to the individual's specific frequency sensitivity. It allows for a more personalized and precise word recognition testing approach, considering the individual's hearing characteristics at a specific frequency of 2 kHz.

Ensuring the accuracy of WRS test results is crucial by employing research-backed methods. Another important aspect of best practice is carefully selecting the word list and ensuring the appropriate number of words is used during the test. Let's delve deeper into exploring WRS test materials.

These are two standardized word lists and the most used lists when performing the WR test. Each is comprised of 50 words; however, many hearing care professionals present only half of the list to save valuable clinical time. This approach may be invalid and unreliable. Why?

Research has shown that the words comprising the first half of these standardized lists are more difficult to understand than the second.

Rintleman showed that the average difference between ears when presenting the first half to one ear and the second half to another was 16%. A solution lies in using re-ordered lists by difficulty, offering a screening approach. Hurley and Sells' 2003 study provides a valid alternative, potentially saving substantial testing time.

Hornsby and Mueller (2013) propose using the Hurley and Sells Auditec NU-6 Ordered by Difficulty list (Version II) via recorded word lists. The list comprises four sets of 50 words each. The examiner can conclude the test after the initial 10 or 25 words or complete all 50 words. Studies have shown that approximately 25% of patients require only a 10-word list. Instructions accompany the list.

Otolaryngologists often compare the WRS between ears to determine if additional testing is needed to rule out certain medical conditions. The American Academy of Otolaryngology recommends referring patients for further testing when the WRS between ears shows an asymmetry of 15% or greater. This asymmetry is not significant enough to warrant a referral for additional testing.

What constitutes a significant difference? Thornton and Raffin (1978) developed a statistical model against which the WRS can be plotted to determine what is statistically significant based on "critical difference tables." Linda Thibodeau developed the SPRINT chart to aid in interpreting WR tests. It utilizes data from Thornton and Raffin and that obtained by Dubno et al. This chart helps evaluate the asymmetry and determine if a WRS is close to PBMax.

Here are some dos and don'ts from an Audiology Online presentation by Muellar and Hornsby.

  1. Always use recorded materials, such as the shortened-interval Auditec recording of the NU-6.
  2. Choose a presentation level to maximize audibility without causing loudness discomfort, utilizing either UCL-5 or the 2KHz –SL method.
  3. Use the Thornton and Raffin data, incorporated into Thibodeau's SPRINT chart, to determine when a difference is significant.
  4. Use the Judy Dubno data in Thibodeau's SPRINT chart to determine when findings are "normal."
  5. Utilize the Ordered-by-Difficulty version of the Auditec NU-6 and employ the 10-word and 25-word screenings.

  1. Avoid live-voice testing.
  2. Steer clear of using a presentation of SRT+30 or SRT+40.
  3. Avoid making random guesses regarding when two scores are different.
  4. Refrain from conducting one-half list per ear testing unless using the Ordered-by-Difficulty screening.

In conclusion, adopting modern methods and evidence-based practices can improve the accuracy, efficiency, and validity of word recognition testing. Staying informed and using best practices is crucial for mastering this critical aspect of hearing assessments and giving your patients the best possible care.

 

Other Good Reads: A Quick Guide to Speech Audiometry Using the GSI Pello Audiometer


 

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