Speech Audiometery (2)

Most comfortable loudness level

• Determining the hearing level at which the speech is most comfortably loud for the patients and it can provide some useful information

• Most normal hearing people find the speech most comfortably loud at 40 to 55 dB above threshold

• MCL may be determined binaurally or monaurally under earphone or it could be tested in sound-field

• Test material:

Test applied using continuous discourse (cold running speech) as it gives the patient the opportunity to listen to speech as it fluctuates over time

• Instructions:

Patient should indicates whenever the perceived speech is comfortably loud

• Presentation level

Test may starts at hearing level slightly above patient’s SRT (for example 5 dB SL)

• Test steps

From this level ( 5 dB above SRT), the intensity is increased gradually ( 5 dB steps)

At each level the patient should indicates whether the speech “ too soft”, “ too loud” or “ most comfortable”

Several levels should be tested, below and above the first level selected as the most comfortable level

• Uses Martin and his colleagues (1998) found that

MCL is not used by most audiologists except in HAs evaluation

Uncomfortable Loudness level

• It measures hearing level at which the speech uncomfortably loud to the patient

• In normal hearing subjects, ULL usually extends up to the maximum audiometer limit (100 to 110 dB HL)

• For some patients with hearing loss, this level may be much lower when expressed in dBs above the SRT

• Instructions, test materials and test steps

All the same as MCL except, that patient indicates whenever speech uncomfortably loud

• Uses

It’s useful in assessing patient candidacy for HAs

To set the maximum output for HAs

• Other names

Threshold of discomfort (TD)

Tolerance level

Loudness discomfort level ( LDL)

Range of comfortable Loudness/

Dynamic range

• RCL or DR is the mathematical difference between the SRT and the ULL

• Normal hearing people have RCL of 100 dB HL or more for either speech or pure tone

• Uses

Determining HAs selection

Rehabilitative measures

Speech Recognition tests

• Some patients with speech understanding difficulties may benefit from making the speech level louder like patients with CHL

• However, many patients with SNHL showing no benefit from raising the level of speech and their complain is I can hear but I can’t understand !!!

• Previously, the term Speech discrimination score (SDS) was used to describe patient’s understanding of speech stimuli

• Nowadays, terms speech recognition score (SRS) and word recognition score (WRS) used. As SDS means distinguishing among

different stimuli, Whereas, SRS implies the patient

understanding of single item presented

• Word recognition score (WRS) term used when the presented stimuli are words

Test materials

• For any test to be useful it should be:

1. Reliable:

Test shows similar scores with multiple administrations ( test-retest reliability)

2. Valid:

a) Measures what intended to measure

b) Favorable

c) Not change with any additional alteration ( for example noise introduction )

• Two responding formats have used:

1) Open-response ( select answer from infinite number utterances)

2) Closed response ( choose answer from given group of words, sentences or pictures)

1- Phonetically Balanced (PB) Word lists

• Lists that contain all phonetic elements of connected English speech

• First, they were 20 lists with 50 words in each list by Egan

• Then, elimination done by Hirsh and others

(1952) to most of Egan’s words and 200 words only have been saved and divided into 4 lists ( 50 words in each) and these lists known as ( CID auditory lists W-22)

• Because many of the words in the word lists were not familiar to children, Haskins (1949) developed 4 lists of 50 words within the vocabulary level of children

They are presented either using CD or any other recorded forms or using MLV

• Scores calculated for both children and adults by counting number of correct responses out of 50 and multiplying that by 2%

2-Consonant- Nucleus-consonant Lists

• As in English language is difficult to have truly phonetically balanced word lists, Lehiste and Peterson (1959) prepared another 50 phonemically balanced word lists

Monosyllabic words contained consonant- vowel (one) or diphthong- consonant (boy)

Scored the same way as PB word lists

• Tillman and Carhart (1966), developed same type of lists (4) ( Northwestern University Test No.6- NU-6), which they have found of high reliability.

• NU-6 and CID W-22 remain the most popular materials for word recognition testing

3-High- frequency emphasis lists

• 2 lists of 25 words, each word carrying 4 %

• This list designed to measure the word recognition scores for patients with high frequency hearing loss who are known to have speech understanding difficulties

• Each word contains vowel /I/ like in kick and preceded and followed by a voiceless consonants

4-Nonsense-syllable lists

• 2 lists with 25 nonsense syllables in each

• Everyone contains a two-syllable utterance, with each utterance produced by consonant followed by vowel (CVCV)

• It has an advantage that each phoneme can be scored individually

5- Short Isophonemic word lists

• 15 lists with consonant-vowel-consonant words (30 phonemes)

• Each phoneme scored individually

• No significant differences were found between scoring short isophonemic word lists and CID W-22 test (Tonry, 1988)

Word Recognition testing with half lists

• Word recognition testing time can be saved by restricting the number of used words

Using half of each word list instead of full one

Using 25 words instead of 50 words

Giving each correct response 4%

• Some arguments against using half lists

1) Half of a list may produce fewer audible

sounds than the second half

2) Differences in difficulties of discriminations between tow half of the lists

3) Splitting of the list may lost them their phonetically balanced criteria

• However, some scientists do disagree these points as follow

1) Phonically balanced is not necessary in diagnostic tests and half lists measuring same as what full lists measure (Tobias, 1964)

2) 25 lists as reliable as 50 lists, ( Thornton and Raffin, 1978)

3) Most audiologists prefer half word lists ( Martin and colleagues, 1998)

Testing monosyllabic with closed-

response set

• California Consonant test:

A test for discrimination problems for people with high frequency hearing loss

California test ( 100 words in two lists and the patient should tick one of four possibilities presented to him in a paper

• Picture Identification Task (PIT)

A test for word recognition among adults who cannot give verbal responses and had difficulty in selecting items from a printed sheet

CNC words presented in pictures with different 4 rhyming words

• Word Intelligibility by picture Identification (WIPI) test:

A test developed for testing children word

recognition ability who either unable or unwilling to respond in the adults way.

Series of 25 cards presnted to the child, each card contains 6 pictures ( 4 pictures might be possibilities for the stimulus, the rest two even not part of testing words, they are just presented to decrease chance response)

Testing speech recognition using

sentences

• Jerger, Speaks and Trammell (1968) presnted their objection against using single words in testing speech recognition

Words are not provide enough information about the time domain of speech

• However, they back to criticize using open message set, as it may affected by memory and learning from the repetition

Good guessers also may show better scores of those with same speech recognition abilities

• Sentences tests for speech recognition advised by Jerger and his colleagues as follow;

Ten synthetic sentences with 7 words in each

Sentences are meaningless and not the same in their difficulty level

They are recorded on CD

Patient responding is to indicate the number belongs to the sentence heard

Test known as synthetic sentence Identification (SSI)

Test stated to be not sufficiently difficult when presented in quiet so, competing connected discourse presented that is varied in its level

Stimuli, materials, response method

• If recorded material used, calibration signal should be included to make the VU meter needle on the middle

• If MLV is used, the audiologist should set in front of the microphone and speaks directly into its diaphragm

• If monosyllables are used, carrier phrase should be preceded, the last word of it should be at proper loudness so the VU meter needle peaks at 0

• The stimulus word should be uttered with the same stress

• 3-5 seconds should be left between tow presentation to give the patient a chance for responding

• Patients can response by

Repeating orally,

Writing down the presented words, or circling the correct answer

Pointing to picture or object

• Pre-recorded materials are preferred on MLV because

It represents the difficulty patient has more than MLV

It could be standardized to allow comparisons among single patients

Presentation level

• Test preferred to be administer at least 2 levels to find the level of maximum patient score,

5-10 dB above the MCL (usually show the maximum patient performance)

90 dB HL ( to check the roll-over)

• One level is enough if the patient score is 100%

• More than 2 levels testing audiologists perform to more fully define PI function (next lecture)

Test procedure

• Before the test administration, audiologist should decide about the following;

1. Method to deliver the stimulus ( pre-recorded material is recommended than MLV)

2. Type of used material

3. Method of responding

4. Presentation level

5.If more levels to be tested

6. Whether any competing signal will be used

7. Whether masking needed and at which level and what is its type

Test steps

• Complete the MCL and ULL bilaterally

• Select the appropriate material (PB word lists)

• Set up audiometer for speech audiometery

• Channel 1 for stimulus presentation and channel 2 for masking whenever needed

• If the patient in separate booth, make sure that the talkback system and intercom are sufficiently loud to hear the patient response clearly

• Make sure the patient seated with microphone well positioned to pick up the patient responses clearly

• Instruct your patient … next slides

• Place the earphone on the patient and make sure you can see your patient face after the door is closed

• Start ear with better hearing first

• Start at either 30 dB SL or 5-10 dB above MCL

• Whole list should be completed and scored immediately, expressed in %

• Increase by 10 dB and present another list, plot the score

• Repeat the previous step until you get 100 % or you reach patient’s ULL

• Start testing the lower levels (below PTA by 10 dB), proceed to lower levels until patient show 10% and plot the scores

• Now complete the graph and diagnose

• Instructions

It should be given orally, even if a printed form has been provided

Gestures and sign may be used, however patients who are not able to comprehend the oral instructions usually cannot participate in speech recognition tests

If patient will response orally, the microphone and accepted response should be demonstrated

If writing to be the method of responding, the proper form and the a firm surface should be provided

Ensuring the patient understanding is essential to save your testing time and avoid repetition

Example for instructions

• You are going to hear someone speaking single words through the earphones, one ear at a time.

• The words spoken slowly like BUS..Fun… Shop… Toy..

• At the beginning they will be comfortably loud but gradually they will become quieter (or louder) and then they will become much louder or (quieter)

• Please listen carefully and repeat after each word whatever you think you heard

• Even if you hear part of the word or single sound

like /a/, /o/, /ch/, please repeat because it adds to your score

• Do you have any questions?

Recording of Speech recognition test

results

• Test results recorded on the audiometeric worksheet in form of percentage for correctly identified words

• More information to be recorded:

Level of presentation

If masking administered

Type of noise and EML

• Many audiologists test speech recognition binaurally to demonstrate the advantage of speech processing binaurally

General assessment guidelines of word

recognition tests