Speech Audiometry and Types of Speech Tests

Speech Recognition Threshold (SRT)
  - Some refer to it as "recognition," while others use the term "reception."   - Clinically defined as the softest level at which one can understand speech.   - Technically, it is the softest level at which one can identify half of the stimulus words.   - Spondees: Words used for determining SRT, which are two-syllable words with equal stress on each syllable.
    - Examples of Spondees:
      - Playground
      - Baseball
      - Snowman
      - Ice cream
      - Bathtub
      - Toothpaste
      - Whitewash
      - Hot dog
      - Birthday
      - Airplane
      - Cowboy
Speech Detection (Awareness) Threshold (SDT/SAT)
- Important to note that SRT and SDT/SAT are NOT the same.
Word Recognition Score (WRS)
- Also known as Speech Recognition Score (SRS) or Speech Discrimination Score (SDS).
Most Comfortable Loudness Level (MCL)
- Sometimes referred to as Most Comfortable Listening Level.
Uncomfortable Loudness Level (UCL)
- Also referred to as Loudness Discomfort Level (LDL).

Speech Recognition Threshold (SRT)
- Specifies the softest sound level at which speech can be understood. - Clinically determined by identifying the level at which half of a set of spondee words can be recognized correctly.
Procedure for Establishing an SRT
  1. Familiarize the client with spondee words at a comfortable listening level.
     - This involves presenting the list at a suprathreshold level first.
  2. Obtain a threshold using a method similar to pure-tone threshold: decrease level by 10 dB and increase by 5 dB.
ASHA Method for SRTs
  1. Familiarize the client.   2. Start at 30-40 dB over the estimated SRT.
  3. Present one word, then adjust level:
     - Drop by 10 dB until a word is missed.
     - Present a second word; if two words are missed, increase by 10 dB to find the starting point.
  4. Present two words at the new starting point.
     - Drop by 2 dB and assess responses.
     - For a valid testing point, at least 5 out of 6 responses must be correct.
  5. Continue adjusting until five out of six responses are missed.
     - Subtract the number of correct responses from the starting point and add one for the final SRT.

Intra-test reliability must be considered; typically, the three-frequency or two-frequency average is found to be within 10 dB of the SRT (noted ranges may vary: +/- 10 dB for some, while others cite +/- 12 dB).
Variations in techniques among audiologists include:
  - Using blocks of words (3-4)
  - Using two-word presentations
  - Employing standard protocols like the ASHA method
  - Utilizing the Hughson-Westlake method, similar to pure tone testing.

Various testing modifications and adaptations for children can include:
- Multiple choice answers with visual aids (e.g., pictures)
- Testing with body parts referenced for clarity.
If establishing SRT is unsuccessful, the audiologist may establish a Speech Detection Threshold (SDT):
- Patients indicate when they hear speech or voice without having to repeat words.
- SDT is typically found to be worse than the best pure-tone threshold measured.

Word Recognition Scores (WRS)
- These scores are measured in percentages and represent the proportion of one-syllable words identified correctly at a comfortable listening level (MCL). - Testing is performed at MCL, calculated as SRT + 30 dB or 40 dB above a predetermined sensation level (dBSL). - Phonetically balanced lists of one-syllable words are used for the assessments.
Procedure for SRS/SDS
  1. Find the comfortable listening level (MCL).   2. Present 10 words.
     - Dr. R indicates that this may be insufficient for reliable assessment.
  3. If any words are missed, present an entire half-list (25 words).
  4. If the listener misses more than four words, present the complete list (50 words) to assess comprehension.
SRT vs. WRS Distinctions
  - SRT utilizes spondee words, while WRS involves a carrier phrase (e.g., "Say the word…" or "Point to…").   - No pause is maintained between carrier phrase and target word; it should sound natural, resembling a conversation.
  - Various research institutions and universities have created different standardized lists for testing, such as:
    - CID W22
    - NU-6
    - PBK (specifically for children).

Word Recognition and Site of Lesion
  - Conductive Hearing Loss:
     - Tend to not significantly affect discrimination abilities as the cochlea remains intact and distortion is absent.   - Cochlear Hearing Loss:
     - Associated with decreased word discrimination due to damage and distortion within the cochlea.
  - Retrocochlear Losses:
     - May present as discrimination rollover with worse scores at elevated intensity levels.
     - These losses may appear differently from sensorineural hearing loss (SNHL) due to markedly low WRS.
Other Important Measures
  - Most Comfortable Loudness Level (MCL).
  - Uncomfortable Loudness Level (UCL).
  - Dynamic Range or Range of Comfortable Loudness (RCL):
    - Defined mathematically as: $ext{RCL} = ext{UCL} - ext{SRT}$ .

Recruitment:
- A perceptual phenomenon where a mere slight increase in sound intensity results in a disproportionate increase in perceived loudness, leading listeners, especially those with hearing loss, to say things like, "You don’t have to yell at me" when sound levels are minimally elevated.

Importance of SPIN Testing:
- Traditional SRT and WRS testing is typically performed in quiet sound booth environments, which do not mimic real-world noisy surroundings. - Acknowledges that everyday environments often have variable noise levels that can impede auditory comprehension.
SPIN Testing Goals:
- Evaluating a person's ability to function within realistic listening situations. - Assesses the signal-to-noise ratio between the spoken words and background noise.
Types of Background Noises:
- Speech babble (e.g., restaurant ambiance). - White noise (wideband and narrowband).
SPIN Test Variants:
  - SIN Test
  - QuickSIN Test
  - BKB-SIN Test
Auditory Figure-Ground Testing:
- Within the central auditory processing domain, this testing assesses the ability to distinguish auditory signals in noise, further confirming its significance in auditory assessments.