The Weber test is a useful, quick, and simple screening test for the evaluation of hearing loss. The test can detect unilateral conductive and sensorineural hearing loss. The outer and middle ear mediate conductive hearing. The inner ear mediates sensorineural hearing. The Weber test is often combined with the Rinne test to detect the location and nature of hearing loss.
To understand the Weber test, one has to understand the basic anatomy of hearing.
The ear anatomically consists of the sound-conducting system (outer and middle ear) and sound-transducing system (the cochlea).
The purpose of the outer ear is to direct sounds onto the tympanic membrane. The sound vibrations are then transmitted through the middle ear via the ossicular chain before it reaches the cochlea. The cochlea plays an important role in transducing these vibrations into nerve impulses via the auditory nerve (vestibulocochlear nerve) which is then delivered along the central pathways to the auditory cortex where it is processed and perceived as sound. This pathway is termed air conduction. However, sound can also be transmitted via bone conduction where vibrations are transmitted via the skull and delivered directly to the cochlea which is buried within the temporal bone.
Hearing loss may occur due to interruption at any point along these pathways.
The Weber test, along with its paired Rinne test, is commonly used to distinguish the site and likely cause of hearing loss. Conductive hearing loss is due to problems with the sound-conducting system, while sensorineural hearing loss is due to problems with the sound-transducing system, the auditory nerve or its central pathways. Occasionally, one can get a mixed hearing loss, which is a combination of the 2 hearing loss.
In normal hearing, an individual will hear equally on both sides of the ear. The Weber test is a test of lateralization and is of most value useful in those with an asymmetrical hearing loss.
Weber Test Principles
The inner ear is more sensitive to sound via air conduction than bone conduction (in other words, air conduction is better than bone conduction).
In the presence of a purely unilateral conductive hearing loss, there is a relative improvement in the ability to hear a bone-conducted sound. This can be explained by the following:
In the presence of sensorineural hearing loss, the sound will be perceived louder in the unaffected ear which has the better cochlear.
An ideal tuning fork of choice for the Weber test would be one that has a long period of tone decay, in other words, the tone maintains/lasts long after the tuning fork has been struck, and cannot be detected by sense of bone vibration, therefore preventing misinterpretation of the vibration as sound.
512-Hz Tuning Fork
In clinical practice, the 512-Hz tuning fork has traditionally been preferred. At this frequency, it provides the best balance of time of tone decay and tactile vibration. Lower-frequency tuning forks like the 256-Hz tuning fork provide greater tactile vibration. In other words, they are better felt than heard. Higher-frequency tuning forks, for example, the 1024-Hz tuning fork, have a shorter tone decay time.
256-Hz Tuning Fork: An Alternative
The 256-Hz tuning fork, along with 128-Hz tuning fork, is commonly used as part of neurological examination due to their greater tactile vibration characteristic. However, evidence suggests that the 256-Hz provides better reliability when compared to the 512-Hz. ,
The audiometric tuning fork generally consists of the tines (the U-shaped prongs), the stem, and the footplate.
Striking the Tuning Fork
Performing Weber Test 
Unilateral Sensorineural Hearing Loss
Note: an abnormal/negative response on the affected ear (BC greater than AC) can also occur in a severe sensorineural hearing loss, also called a dead ear. This is termed a "false negative." Rinne "true negative" only occurs if there is a conductive hearing loss element. However, when testing a dead ear, the bone conduction is perceived to be heard louder than air conduction due to cross-over of bone conduction detected by the opposite normal-functioning cochlear, resulting in a Rinne false negative.
Unilateral Conductive Hearing Loss
Symmetrical Conductive Hearing Loss
The Rinne test is the complement for the Weber test. They are screening tests and do not replace formal audiometry. It is important to note that further examinations and investigations such as otoscopy, audiometry, tympanometry, and imaging may be required to correctly diagnose the cause of the hearing loss and allow appropriate management.
Possible Causes (Non-Exhaustive) of Hearing Loss
Conductive Hearing Loss
Outer Ear Causes
Middle Ear Causes
Sensorineural Hearing Loss
Inner Ear Causes
The weber test is used by multiple health professionals that includes the primary care provider, nurse practitioner, ENT surgeon, neurologist and internist to evaluate the patient's hearing. The test is almost always used along with the Rhinne test to differentiate between conductive hearing loss from a sensorineural hearing loss. This will guide the clinician to the need for further examination, investigation, and management. In addition, the Weber and Rinne tuning fork tests can be used to confirm audiometric findings, particularly when the audiogram is not consistent with clinical findings. In the assessment of a patient with bilateral conductive hearing loss, the Weber test is a quick and useful test for the otorhinolaryngology (ENT) surgeon to help determine which side of the ear to operate on first. Usually, the ear with the more significant conductive hearing loss is preferred.
|||Browning GG,Swan IR, Sensitivity and specificity of Rinne tuning fork test. BMJ (Clinical research ed.). 1988 Nov 26 [PubMed PMID: 3146371]|
|||Browning GG,Swan IR,Chew KK, Clinical role of informal tests of hearing. The Journal of laryngology and otology. 1989 Jan [PubMed PMID: 2646384]|
|||Recommended procedure for Rinne and Weber tuning-fork tests. British Society of Audiology. British journal of audiology. 1987 Aug [PubMed PMID: 3620757]|
|||Walsh B,Usler E,Bostian A,Mohan R,Gerwin KL,Brown B,Weber C,Smith A, What Are Predictors for Persistence in Childhood Stuttering? Seminars in speech and language. 2018 Sep; [PubMed PMID: 30142641]|
|||Kelly EA,Li B,Adams ME, Diagnostic Accuracy of Tuning Fork Tests for Hearing Loss: A Systematic Review. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery. 2018 Aug; [PubMed PMID: 29661046]|
|||Kong EL,Fowler JB, Rinne Test 2018 Jan; [PubMed PMID: 28613725]|