Audiometer, though considered as the basic equipment to assess the function of hearing, has undergone significant transformation since its inception almost 100 years ago. The audiometer though emerged as an instrument to check hearing levels across a given range of frequencies, has today taken a vast spectrum of roles in determining various aspects of hearing function. Eventually as the role of Audiometer widened, there emerged the requirement of classifying the Audiometer based on the tests done & the test facilities made available. Accordingly, the audiometer which was initially introduced to measure & quantify the hearing level was sooner exposed to meet & explore various other related functions of hearing. The term Audiometer still prevailed for all these equipments though the Audiometer was categorized into different types. Now, all these were the events in history, in the pre-digital era. We are now into the digital era of this modern world ruled by technology, with technological advances influencing & penetrating into this field of Audiological Science & Audiological instrumentation with great success. Integration of various technologies led to the development of precision devices that would facilitate objective measurements of the functions related to hearing mechanism. The term Audiometer started loosing significance & marked the beginning of its disappearance in reference to the precision high end objective devices. Hence a renewed look (by this author) gave birth to a realization towards the need for a novel nomenclature in this digital era with a broader concept in terming & classifying the most sacred instrument – “The Audiometer”.
Audiometer – The prevailing definitions:
Audiometer is an electronic instrument designed for the measurement of hearing sensitivity, and for the calibrated delivery of supra-threshold stimuli. (Stach, B.A, 2003. Comprehensive Dictionary of Audiology, Illustrated, Delmar Cengage Learning; 2nd Revised edition.)
An Audiometer is an electronic instrument, used by an Audiologist to quantify hearing. (Stach, B.A, 1998. Clinical Audiology: An Introduction, Cengage Learning).
There are several types of Audiometers, that are classified primarily based on their functions. Initially, it was classified broadly into Clinical Audiometer & Screening Audiometer based on the extent of functions that the Audiologist might want to use for hearing assessment.
The Audiometer is an essential tool of the Audiologist for measuring hearing function. An Audiometer is an electronic instrument designed for the presentation of calibrated auditory stimuli to transducers. (DeRuiter, M., Ramachandran, V. 2016. Basic Audiometry Learning Manual, Plural Publishing, 2nd Edition)
An Audiometer is an electro-acoustic device that produces controlled levels of test tones and signals intended for use in conducting diagnostic hearing evaluations and assist in the diagnosis of possible otologic disorders. (Code of Federal Regulations, FDA, 1985-1999, Pg. 300)
An Audiometer is a primary tool used by the Audiologists in the assessment of peripheral hearing sensitivity. (Frank E.Musiek, Jain A Baran, Jennifer B Shinn, Raleigh Jones, 2011, Disorders of the Auditory System, Pg. 63, Plural Publishing)
Classification of Audiometers –The prevailing categories:
International Electro-technical Commission (IEC), 1980 classifies Audiometers into 5 types:
This classification is based on the range of features and complexity of the functions available within the equipment for the assessment of hearing function. The number of features and the extent to which it assesses the various hearing functions differs in each of these types and these features & functions generally decreases as we proceed from Type -1 Audiometer to Type -5 Audiometer. As such, these types are broadly classified as:
Type -1 Audiometer ®Advanced Diagnostic Audiometer.
Type -2 Audiometer ®Diagnostic Audiometer
Type -3 Audiometer ® Simple Diagnostic Audiometer
Type -4 Audiometer ® Screening Audiometer
Type -5 Audiometer ® Simplest Audiometer
A very brief description of these audiometer types is given as below:
Type-1 Audiometer: (Advanced Diagnostic Audiometer)
Type-2 Audiometer: (Diagnostic Audiometer)
Type-3 Audiometer: (Simple Diagnostic Audiometer)
Type-4 Audiometer: (Screening Audiometer)
Thus, its seen that Audiometers are classified according to the range of test signals they generate, according to the mode of operation or according to the complexity of the range of auditory functions they test. In such a classification, the Audiometer is not equipped to measure all the aspects & functions related to hearing mechanism.
Though Audiometers, in early 1920’s & 1930’s were mainly used to measure the hearing, confining the audiologic services to the measurement of hearing level to certify the degree of hearing handicap; developments in the field of hearing measurements for diagnostic, hearing conservation and rehabilitation purposes have resulted in the availability of a wide range of audiometers suited to assess more specialized functions of hearing mechanisms. In addition it is possible to consider the audiometer in terms of a set of functional units which can be specified independently. By specifying these functional units it is then possible to specify the performance of other audiometric equipment which uses these units.
Proposed Definition for Audiometer: (Proposed by this author)
An Audiometer is an electronic device that is capable of generating different calibrated acoustic stimuli, necessary for the examiner to assess various aspects of hearing mechanism.
Functions of Audiometer:
Functionally, Audiometer is used to:
Applications with Audiometer:
Audiometer can be used as:
Components of Audiometer:
Although the micro-components of audiometer might vary with reference to the purpose with which it is manufactured to assess; any & all Audiometers basically consists of:
So, if Audiometer is what it was initially considered as an equipment that is used in the measurement of hearing & hearing disability, then there exists similar equipments which could be used for the assessment & measurement of hearing & hearing disability; which are known by the following names:
According to World Report on Disability, prepared by WHO (World Health Organization), “disability is a complex, dynamic, multidimensional & contested one”. Hearing disability, which is regarded as one of the most invisible disability (hidden disability), is therefore a complex multidimensional experience that poses several challenges for measurement. As such any single equipment would not be sufficient enough to precisely assess & measure the hearing function to suit the wide range of clinical population, considering the high rate of associated disorders that prevail along with hearing impairment and the prevalence of hearing impairment right from birth. While the conventional so called ‘early audiometers’ need patient cooperation for the measurement of hearing function; very often Audiologists have to depend on sophisticated equipments (OAE equipments & Evoked Potentials (EP) equipments) to confirm the hearing function. This is very likely in case of newborns, difficult to test patients & patients who has limited access to competent communication. Hence the Audiologists need to have multiple access to equipments to measure the hearing and subsequently confirm the disability factor.
Going by the functional definition of Audiometer, all these devices (Immittance Audiometer, OAE equipment, EPequipment) are electronic devices that generates different acoustic signals necessary for the Clinical Audiologist to assess various aspects of hearing mechanism. This is well substantiated with the presence of basic components that are common in all these equipments. (i.e., Oscillator, Attenuator, Interrupter & Transducers; however in different forms).
Audiometer has changed its form & function since its inception almost 100 years back. It was initially a huge bulky equipment which comprised of only analog components in the making. Present day Audiometer (and perhaps all future audiometers) has witnessed the transition from its old form towards a new generation of Audiometers whose making is facilitated with exclusive digital technology, suited to perform multiple functions that would aid in the measurement of hearing and precisely categorize the disability factor. Thus the present day audiometer would be embedded with microprocessors and programmers that would aid in precise detection of various hearing functions.
Thus it is very much evident that various approaches need to be considered and adopted to accurately measure the hearing disability. A single measure with a single equipment would be too less to bring out this “Hidden Disability” into light, given the wide nature of circumstances that hides it.
Hence, the necessity to have a broader classification of Audiometer types arises.
Proposed Nomenclature for Audiometer: (Proposed by this author)
Here, Audiometers are classified based on the following factors:
Here, no attempt is made to make any changes in the ‘Standards’; rather this document focuses on a broader conception & classification of the term ‘Audiometer’; considering the multiple assessment procedures that could be utilized to include and evaluate various aspects & functions related to hearing mechanism. This classification would enable in categorizing all equipments belonging to hearing screening objective under Type –I Audiometer termed as “Screening Audiometer” (SA); all equipments that employ diagnostic measures in the assessment of hearing functions & rely on behavioral responses under Type -II Audiometer termed as “Comprehensive Clinical Audiometer” (CCA); all equipments related to the measurements of middle ear functions under Type –III Audiometer termed as “Immittance Audiometer” (IA); all equipments that employ an objective method of response recording during the process of hearing assessment under Type –IV Audiometer termed as “Advanced Diagnostic Audiometer” (ADA); all equipments that evaluate the balance function using acoustic stimuli as the input stimulus under Type –V Audiometer termed as “Vestibular Audiometer” (VA). Thus a clear cut distinction prevails in the classification of Audiometers in this new era of digital & advanced digital technology, thereby bringing in a wider dimension towards the conception of this sacred equipment –The Audiometer!
WHO, 2011. World Report on Disability.
If Audiology is the science of ear & hearing, then definitely Audiologists should be the scientific group of professionals who have mastered the art of science of ear & hearing. I wouldn’t use the term “master”, rather let’s us say that Audiologists are the group of scientific professionals, who have specialized in the field of “Hearing Health & Rehabilitation”. Yes.., that’s the term, we need to promote – “ Specialist in Hearing Health & Rehabilitation”.
Now, if we are actually the “Specialists in Hearing Health & Rehabilitation”, then the next question arises –“Are we performing as Specialists in this field of Hearing Health & Rehabilitation ?” Specialists as the term indicates refers to a person who is an expert in the field of his learning. So, Audiologists, being an expert in the field of Hearing Health, need to dispense his professional liabilities with the kind of knowledge & skillful performance in a very independent manner.
Now, here lies the second matter of inquiry. How independent are we in our clinical practice? Are we, discharging our professional duties in a purely independent manner? One might wonder with the term independency, and keep guessing, what it could mean in our clinical practice. Let’s describe few situations of independency, for an aggregate understanding:
These are only few of the common factors that proves to be a deciding factor towards maintaining independency in the clinical practice of Audiology. Therefore, every Audiologist should nurture a retrospective attitude in building, maintaining, and taking forward a healthy independent practice; thereby ensuring the dignity of our profession.
Having said that, the investigation automatically leads to the next question. Yes, Dignity!
With regard to our field, with regard to the discharge of our duties, with regard to the dispensation of our clinical services, we can consider the term ‘Dignity’ from various aspects & angles. Although there is hardly any universal agreement on the meaning of the term ‘Dignity’, one thing that is common to the said term is that:-
I have interacted with many of the professionals in the state & outside; only to find that dignity is being compromised at various levels in the execution of our professional duties. I understand that the ‘determinants of dignity’ in our professional practice is multi-folded and is dependent on various factors. Given the multi-faceted dimension, I would like to attract the attention towards couple of loci:
Though the area under discussion is vast, I am limiting my thoughts to these issues faced by the current emerging Audiologists & non-established Audiologists, so that necessary corrections are introduced in their clinical dispensation.
Let me conclude by saying that, every Audiologist have a lifestyle of his or her choice. Let there be Audiologists, who “choose-to-live” a life-style; but let there be no Audiologists, who are “forced-to-live” a life-style!