Word Recognition (WRS)
Purpose
Word recognition testing is a valuable component of the audiometric evaluation. This testing is performed at supra-threshold level. Word recognition testing can be used for a number of purposes including provision of diagnostic information, assessment of supra-threshold speech understanding and cross-check of pure tone sensitivity.
There are several reasons why word recognition testing is performed. An important function of word recognition testing is its potential value as a diagnostic indicator. Typically, word recognition performance can be predicted by the audiogram. However, in some cases, such as when there is central auditory or retrocochlear dysfunction, word recognition scores may be poorer than expected, alerting the clinician to the possibility of these problems.
Word recognition testing also can be used as an assessment of suprathreshold speech understanding. When considering rehabilitation measures, it is helpful to have knowledge of how a patient understands speech when a sound is made loud enough to hear well. Individuals who have poor word recognition at suprathreshold levels should be counseled as to appropriate expectations for amplification.
Another use of word recognition testing is as a cross-check of pure-tone sensitivity. If word recognition scores are dramatically better than should be expected for a given audiogram, this may be an indication of functional hearing loss. In addition, if word recognition scores are high at very low sensation level relative to the speech reception (or recognition) threshold (SRT), this can also raise concern about functional hearing loss
There are several reasons why word recognition testing is performed. An important function of word recognition testing is its potential value as a diagnostic indicator. Typically, word recognition performance can be predicted by the audiogram. However, in some cases, such as when there is central auditory or retrocochlear dysfunction, word recognition scores may be poorer than expected, alerting the clinician to the possibility of these problems.
Word recognition testing also can be used as an assessment of suprathreshold speech understanding. When considering rehabilitation measures, it is helpful to have knowledge of how a patient understands speech when a sound is made loud enough to hear well. Individuals who have poor word recognition at suprathreshold levels should be counseled as to appropriate expectations for amplification.
Another use of word recognition testing is as a cross-check of pure-tone sensitivity. If word recognition scores are dramatically better than should be expected for a given audiogram, this may be an indication of functional hearing loss. In addition, if word recognition scores are high at very low sensation level relative to the speech reception (or recognition) threshold (SRT), this can also raise concern about functional hearing loss
Materials
NU-6 List played via a calibrated audiometric system for accurate
Procedures/Instruction
- Word recognition testing is performed by presenting open-set monosyllabic words (words of one syllable) at a fixed intensity level that is audible to the patient.
- The patient repeats back the word that is presented.
- The percentage of correct responses is calculated.
The two methods that are available for presentation of stimuli are monitored live voice and recorded materials. In all situations, recorded materials are the method of choice for stimulus presentation. The use of recorded materials allows comparison of test scores between presenters, between test sessions, and with normative data. Without the ability to compare word recognition scores in this manner, the resulting test data would rarely, if ever, be useful for any purpose.
Typically, a carrier phrase is presented, followed by the stimulus. An example is, "Say the word 'wife'." The patient then responds by repeating the last word of the sentence.
Presentation Level
Performance on tests of word recognition depends to a certain extent on the audibility of speech sounds. In other words, the sounds must be loud enough to be heard. It has been found that, for most normal hearing listeners, the maximum speech recognition performance occurs at a level of about 40 dB greater than the speech recognition threshold (40 dB sensation level, re: SRT). However, depending on the configuration of the hearing loss, some sounds may still be inaudible.
The most efficient strategy for obtaining maximum word recognition performance scores is to present words at a high intensity level, for example, 80 dB HL. For most listeners, this will allow nearly all speech sounds to be audible, and the maximum score for performance can be quickly obtained.
The use of high-intensity levels for presentation of word recognition stimuli is also beneficial for diagnostic purposes, such as determining whether rollover is occurring.
The most efficient strategy for obtaining maximum word recognition performance scores is to present words at a high intensity level, for example, 80 dB HL. For most listeners, this will allow nearly all speech sounds to be audible, and the maximum score for performance can be quickly obtained.
The use of high-intensity levels for presentation of word recognition stimuli is also beneficial for diagnostic purposes, such as determining whether rollover is occurring.
Interpretation/Site of Lesion
WRS score calculation chart
Performance-Intensity Function and Rollover
For most individuals with normal auditory function or purely cochlear hearing loss, maximum word recognition performance is maintained at high intensity levels. The term rollover is used to describe the phenomenon of decreased word recognition ability with increasing intensity levels. This phenomenon often is observed in cases of retrocochlear pathology, and therefore can be used as a diagnostic indicator.
The presence of rollover can be observed by testing word recognition performance at a number of different intensity levels. The resulting performance can be plotted to obtain a performance-intensity function. A performance-intensity function is a graph of the percentage correct speech score as a function of the presentation level. Such a graph can help the clinician to determine whether performance is normal or whether rollover is occurring.
The initial use of a high intensity level becomes efficient when thinking about the use of word recognition testing for diagnostic purposes. By using a high intensity level, the tester is essentially "beginning at the end" of the performance-intensity function. If a patient performs optimally at the high intensity level, then the tester is cued to the possibility that rollover may be occurring and that lower intensity levels should then be used to develop a performance-intensity function to evaluate this possibility.
The presence of rollover can be observed by testing word recognition performance at a number of different intensity levels. The resulting performance can be plotted to obtain a performance-intensity function. A performance-intensity function is a graph of the percentage correct speech score as a function of the presentation level. Such a graph can help the clinician to determine whether performance is normal or whether rollover is occurring.
The initial use of a high intensity level becomes efficient when thinking about the use of word recognition testing for diagnostic purposes. By using a high intensity level, the tester is essentially "beginning at the end" of the performance-intensity function. If a patient performs optimally at the high intensity level, then the tester is cued to the possibility that rollover may be occurring and that lower intensity levels should then be used to develop a performance-intensity function to evaluate this possibility.
Management
Works Cited
Gelfand, Stanley A. Essentials of Audiology. Thieme, 2016.
DeRuiter, Mark, and Virginia Ramachandran. Basic Audiometry Learning Manual. Plural Publishing Inc., 2017
DeRuiter, Mark, and Virginia Ramachandran. Basic Audiometry Learning Manual. Plural Publishing Inc., 2017