WHAT IS AUTOMATIC AUDIOMETRIC TESTING?

Factors affecting audiometric testing results

PART TWO

Automatic vs manual test procedures

This is the second in series of articles, where we are going to break down factors that affect the quality of testing results.

Following standardised test procedures is a significant contributor to the quality of audiometric testing results.

We will deal with automatic audiometric testing in this post and demonstrate why automatic audiometric testing is less superior than manual audiometric testing by a skilled clinician.*

With over 10 years experience in the industry we have come across many instances where automatic testing procedures have been used to produce audiometric testing results.

How do we know?

You can see it in the audiogram- usually a zig zag or inconsistent pattern between frequencies or between ears. Or, where responses are recorded consistently at or below audiometric zero.

How else do we know?

Ask a test candidate when and where they were last tested.

It’s surprisingly common for candidates to comment “the clinician walked out of the room and came back once my hearing test was finished” or “I heard a long beep at the end of the hearing test” Both of these indicate that automatic audiometric testing was in place at the time.  Are these audiometric test results reliable?

What we can say, is that automated pure tone audiometry is never taught or used in audiological practice- in other words, audiologists in clinics do not rely on automated audiometric testing results as a true indication of a person’s hearing thresholds.

Let’s look at the specific clauses in the Australian Standard AS 1269.4 which refer to audiometric testing procedure- and then look at the differences between manual and automatic testing procedures in another blog post.  

In AS 1269.4:2014 - Occupational noise management - Audiometric testing, clauses that refer to automatic test procedures are primarily found in Section 4.6 and related sections.

Here are the key clauses in the Australian Standard:

Clause 4.6 - Automatic Audiometry

This clause explicitly addresses automatic test procedures, stating:

• 4.6.1: Automatic audiometry may be used if the system meets the requirements specified in the standard.

• 4.6.2: The automatic audiometer must comply with AS/NZS 60645.1 (for pure-tone audiometers) and provide equivalent accuracy to manual audiometry.

• 4.6.3: The test environment must still comply with AS 1269.1 (background noise limits).

• 4.6.4: The automatic system must include procedures to detect unreliable responses (e.g., false positives, inconsistent thresholds).

Clause 4.4 - Test Procedures

While Clause 4.4 primarily covers manual audiometry, it implies that automatic testing must follow equivalent procedures, including:

• 4.4.2: Instructions to the subject must be clear (even in automated systems).

• 4.4.3: The test must include appropriate frequencies 500Hz to 8000Hz and include 1500Hz and 6000Hz

Clause 4.7 - Validity of Audiograms

• 4.7.1: Audiograms (whether manual or automatic) must be reviewed for validity.

• 4.7.2: Automatic systems must flag questionable results (e.g., inconsistent retests).

Clause 6 - Record Keeping

• 6.2: Records must indicate whether the test was conducted manually or automatically.

So while it may seem prudent to employ automatic audiometric testing, clauses 4.6.4, 4.7.1 and 4.7.2 imply that there must be manual oversight over any audiometric test results obtained by this method.

We haven't yet seen an automatic system that detects unreliable responses or that flags questionable results. So we can't recommend it.

More importantly, it's impossible to compare wildly different audiometric testing results from automated vs manual test procedures.

We will go through the subtleties of automatic vs manual audiometric testing in the next post.

*The only notable exclusion to the above commentary is the US based WAHTS automated audiometric screening system (which is currently excluded from audiometric testing practices in Australia but has attracted the attention of academic researchers reviewing best practice hearing screening programs).