Pure Tone Audiometry Hearing Test at Dr. Essa Lab

Pure Tone Audiometry at Dr. Essa Lab

Pure Tone Audiometry is the gold standard diagnostic behavioral test used to measure an individual’s hearing sensitivity across a range of frequencies. This non-invasive, highly precise examination determines the quietest sounds a person can hear at different pitches, establishing their hearing threshold levels. By evaluating both air conduction and bone conduction pathways, Pure Tone Audiometry provides critical clinical insights into the functional integrity of the entire auditory system. This includes the outer ear, middle ear, inner ear, and the vestibulocochlear nerve (cranial nerve VIII) pathways leading to the brain. At Dr. Essa Lab, this test is performed using advanced, calibrated diagnostic audiometers inside specialized soundproof booths to ensure maximum accuracy and eliminate environmental noise interference.

The primary clinical value of Pure Tone Audiometry lies in its ability to categorize hearing loss by type, degree, and configuration. Hearing loss is broadly classified into three types: conductive hearing loss, which involves a barrier in the outer or middle ear; sensorineural hearing loss, which stems from damage to the cochlear hair cells or the auditory nerve; and mixed hearing loss, which is a combination of both. By plotting these thresholds on a standardized graph known as an audiogram, audiologists and ENT specialists can pinpoint the exact nature of a patient’s auditory impairment. This detailed mapping is essential for designing effective treatment plans, which may range from medical or surgical interventions to the fitting of hearing aids or cochlear implants.

During the test, the patient is exposed to pure tones—pure sinusoids of specific frequencies measured in Hertz (Hz)—ranging from low pitches (typically 250 Hz) to high pitches (up to 8000 Hz). The intensity of these sounds is measured in decibels Hearing Level (dB HL). By systematically lowering the intensity of each frequency until the patient can barely detect it, the audiologist establishes the sensory threshold. This precise diagnostic tool is indispensable for patients experiencing unexplained hearing decline, persistent ringing in the ears (tinnitus), or balance issues, providing a clear pathway toward effective clinical management and improved quality of life.

Clinical Procedure: What to Expect

Patient Preparation

Preparing for a Pure Tone Audiometry test is straightforward, but following specific guidelines ensures the most accurate results:

• Avoid Loud Noises: Patients must avoid exposure to extremely loud environments, such as concerts, industrial machinery, or loud music, for at least 16 to 24 hours prior to the test. This prevents temporary threshold shift (TTS), which can artificially worsen test results.
• Ear Canal Inspection: It is highly recommended to have a physician inspect the ear canals for excessive cerumen (earwax) before the test. Impacted earwax can block sound waves, leading to an inaccurate indication of conductive hearing loss. If wax is present, professional ear cleaning should be performed.
• Remove Accessories: Before entering the testing booth, patients will be asked to remove eyeglasses, earrings, headbands, or hairpins, as these can interfere with the proper placement and seal of the headphones.
• No Fasting Required: There are no dietary restrictions or fasting requirements for this test. Patients can eat, drink, and take their regular medications as prescribed.
• Manage Acute Illnesses: If you have an active cold, sinus infection, or severe congestion, inform the clinic. Middle ear fluid associated with congestion can temporarily affect hearing thresholds, and it may be advisable to reschedule the test.

During the Procedure

The Pure Tone Audiometry procedure is entirely painless, non-invasive, and typically completed within 20 to 30 minutes. Here is what happens during the test:

• Soundproof Booth: The patient is seated comfortably inside a specialized, acoustically treated soundproof booth designed to block out all ambient background noise.
• Headphone Placement: The audiologist places high-quality supra-aural or insert headphones over or inside the patient’s ears. These are used to test air conduction, sending sound waves through the outer and middle ear to the inner ear.
• Response Mechanism: The patient is given a hand-held response button or instructed to raise their hand or say “yes” whenever they hear a tone, no matter how faint or distant it may seem.
• Testing Frequencies: The audiologist delivers tones of varying pitches (from 250 Hz to 8000 Hz) to one ear at a time. The test begins at an easily audible level and gradually decreases in volume until the patient can no longer hear the tone, establishing the threshold for each frequency.
• Bone Conduction Testing: To isolate the inner ear, the audiologist places a small, vibrating headband device (a bone conduction oscillator) on the mastoid bone directly behind the ear or on the forehead. This bypasses the outer and middle ear, vibrating the skull to stimulate the cochlea directly.
• Masking (If Needed): If there is a significant difference in hearing sensitivity between the two ears, the audiologist may introduce a static-like masking noise to the better ear. This prevents the better ear from “helping” the weaker ear, ensuring that each ear is evaluated independently and accurately.

When is a Pure Tone Audiometry Performed?

Evaluation of Progressive Hearing Loss

Physicians frequently order Pure Tone Audiometry when a patient reports a gradual, progressive decline in their ability to hear. This is common in older adults experiencing presbycusis (age-related hearing loss) or individuals exposed to chronic occupational noise. The test helps determine the rate of decline, the specific frequencies affected (typically high frequencies first in noise-induced loss), and whether the impairment is symmetrical across both ears, guiding appropriate rehabilitative strategies.

Assessment of Sudden Sensorineural Hearing Loss (SSNHL)

Sudden Sensorineural Hearing Loss is considered a medical emergency, characterized by a rapid loss of hearing in one or both ears over a period of 72 hours or less. Pure Tone Audiometry is performed urgently to confirm the diagnosis, determine the severity of the loss, and rule out conductive causes like earwax impaction. Immediate diagnostic mapping is crucial, as early treatment with systemic or intratympanic corticosteroids significantly improves the chances of hearing recovery.

Investigation of Chronic Tinnitus

Tinnitus, often described as a persistent ringing, buzzing, or hissing sound in the ears, is frequently a symptom of underlying cochlear damage or hearing loss. When patients present with chronic tinnitus, physicians request Pure Tone Audiometry to identify any corresponding hearing deficits. Mapping the hearing thresholds helps determine if the tinnitus is linked to a specific frequency loss, which is highly valuable when programming hearing aids with tinnitus-masking features.

Monitoring Ototoxic Medication Effects

Certain life-saving medications, including specific chemotherapy agents (such as cisplatin), aminoglycoside antibiotics (like gentamicin), and high-dose loop diuretics, are known to be ototoxic, meaning they can damage the delicate hair cells of the inner ear. Pure Tone Audiometry is performed before, during, and after treatment regimens to monitor for early signs of subclinical high-frequency hearing loss, allowing oncologists or infectious disease specialists to adjust dosages before permanent communication barriers occur.

Diagnosis of Chronic Middle Ear Pathology

Patients suffering from chronic middle ear conditions, such as recurrent otitis media, otosclerosis (abnormal bone growth in the middle ear), tympanic membrane perforation, or cholesteatoma, require Pure Tone Audiometry to quantify the functional impact of these diseases. By comparing air conduction and bone conduction thresholds, the test measures the exact degree of conductive hearing loss, helping ENT surgeons plan reconstructive middle ear surgeries and monitor post-operative outcomes.

What Does a Pure Tone Audiometry Detect?

Pure Tone Audiometry is highly sensitive and can detect a wide range of physiological and pathological conditions affecting the auditory pathway. The test accurately identifies:

• Normal Hearing: Thresholds between 0 and 20 dB HL across all tested frequencies, indicating healthy outer, middle, and inner ear function.
• Mild Conductive Hearing Loss: Thresholds between 26 and 40 dB HL with a significant air-bone gap, often caused by fluid in the middle ear or earwax.
• Moderate Conductive Hearing Loss: Thresholds between 41 and 55 dB HL, indicating more pronounced mechanical obstruction in the middle ear.
• Severe Conductive Hearing Loss: Thresholds up to 60-70 dB HL, representing maximum conductive loss, often due to ossicular chain discontinuity.
• Mild Sensorineural Hearing Loss: Thresholds between 26 and 40 dB HL without an air-bone gap, indicating early cochlear hair cell damage.
• Moderate Sensorineural Hearing Loss: Thresholds between 41 and 55 dB HL, affecting normal conversational speech understanding.
• Moderately-Severe Sensorineural Hearing Loss: Thresholds between 56 and 70 dB HL, requiring significant amplification for communication.
• Severe Sensorineural Hearing Loss: Thresholds between 71 and 90 dB HL, where speech is inaudible without powerful hearing aids.
• Profound Sensorineural Hearing Loss: Thresholds exceeding 90 dB HL, where even amplified sound may not be clearly perceived.
• Mixed Hearing Loss: Elevated thresholds in both air and bone conduction, with an air-bone gap, indicating coexisting outer/middle and inner ear pathologies.
• High-Frequency Hearing Loss: A sloping audiogram configuration where thresholds worsen at 4000 Hz and above, characteristic of presbycusis.
• Low-Frequency Hearing Loss: A rising audiogram configuration with poorer thresholds at lower frequencies, sometimes associated with early-stage Meniere’s disease.
• Flat Hearing Loss: Similar threshold elevation across all frequencies, often seen in certain genetic or inflammatory conditions.
• Cookie-Bite Hearing Loss: A U-shaped audiogram showing normal hearing at very low and very high frequencies but poor hearing in the mid-frequencies.
• Noise-Induced Hearing Loss Notch: A distinct dip or “notch” in hearing sensitivity typically localized around 4000 Hz, indicating acoustic trauma.
• Unilateral Hearing Loss: Impairment isolated to one ear, which may prompt further imaging to rule out retrocochlear pathology like vestibular schwannoma.
• Bilateral Symmetrical Hearing Loss: Equal hearing loss in both ears, commonly seen in systemic, genetic, or age-related conditions.
• Bilateral Asymmetrical Hearing Loss: Discrepancies in hearing thresholds between the left and right ears, requiring diagnostic masking.
• Air-Bone Gap: A difference of 15 dB or more between air and bone conduction thresholds, confirming a conductive barrier.
• Carhart’s Notch: A specific decrease in bone conduction threshold at 2000 Hz, highly indicative of otosclerosis.
• Presbycusis: Age-related, progressive, bilateral sensorineural hearing loss primarily affecting higher frequencies.
• Acoustic Trauma: Damage to the inner ear from sudden, intense noise exposure, visible as a localized threshold drop.
• Eustachian Tube Dysfunction: Temporary conductive hearing loss due to negative pressure or fluid accumulation in the middle ear.
• Tympanic Membrane Perforation Effects: Conductive hearing loss of varying degrees depending on the size and location of the eardrum tear.
• Ossicular Fixation: Reduced mobility of the middle ear bones, resulting in a consistent conductive hearing loss pattern.

Turnaround Time and Report Access at Dr. Essa Lab

At Dr. Essa Lab, we understand that timely diagnostic results are crucial for effective clinical decision-making and patient peace of mind. Because Pure Tone Audiometry is an interactive, real-time behavioral test, the preliminary audiogram is plotted immediately by the performing audiologist during your session. Following the completion of the test, a qualified audiologist or ENT specialist reviews the findings, correlates them with your clinical history, and drafts a comprehensive, formal diagnostic report.

The finalized, verified report is typically available within a few hours of the test completion, or at most on the same day. Dr. Essa Lab provides multiple convenient ways to access your diagnostic reports. Patients can securely download their digital reports and audiogram graphs directly from the official Dr. Essa Lab web portal or through our dedicated mobile application. Additionally, printed physical copies of the report, complete with professional interpretations and recommendations, can be collected directly from the diagnostic center where the test was conducted.

Pure Tone Audiometry Findings Overview

The following table outlines the key parameters evaluated during a Pure Tone Audiometry test, comparing normal ranges with potential abnormal findings and their clinical implications:

Structure / Parameter Evaluated	Normal Findings	Possible Abnormal Findings
Air Conduction (Right Ear)	Thresholds between 0 and 20 dB HL across all frequencies (250–8000 Hz).	Thresholds > 25 dB HL, indicating mild to profound hearing impairment in the right ear.
Air Conduction (Left Ear)	Thresholds between 0 and 20 dB HL across all frequencies (250–8000 Hz).	Thresholds > 25 dB HL, indicating mild to profound hearing impairment in the left ear.
Bone Conduction Thresholds	Thresholds between 0 and 20 dB HL; overlapping with air conduction.	Thresholds > 25 dB HL, confirming sensory or neural damage within the cochlea or auditory nerve.
Air-Bone Gap (ABG)	Difference of less than 10 dB between air and bone conduction thresholds.	ABG of 15 dB or greater, indicating a conductive hearing loss component (outer/middle ear pathology).
High-Frequency Sensitivity	Thresholds ≤ 20 dB HL at 4000 Hz, 6000 Hz, and 8000 Hz.	Sloping drop or localized notch, indicating presbycusis, noise-induced damage, or ototoxicity.
Mid-Frequency Sensitivity	Thresholds ≤ 20 dB HL at 1000 Hz and 2000 Hz.	U-shaped “cookie-bite” pattern, indicating congenital or genetic hearing impairment.
Low-Frequency Sensitivity	Thresholds ≤ 20 dB HL at 250 Hz and 500 Hz.	Elevated thresholds, suggesting early Meniere’s disease, middle ear fluid, or Eustachian tube dysfunction.
Interaural Symmetry	Symmetrical thresholds within 10–15 dB between both ears.	Asymmetrical thresholds, indicating unilateral pathology that requires further retrocochlear evaluation.

Note: Diagnostic findings should always be interpreted by a qualified healthcare professional together with the patient’s symptoms, medical history, physical examination, laboratory investigations, previous imaging studies, and other relevant clinical information. Additional investigations or specialist consultation may be recommended depending on the findings.

Why Choose Dr. Essa Lab for Pure Tone Audiometry?

• Experienced Healthcare Professionals: Our audiology department is staffed by highly trained, certified audiologists with extensive experience in diagnostic hearing assessments.
• Patient-Focused Care: We prioritize patient comfort and clear communication, ensuring a stress-free testing environment for patients of all ages.
• Quality Diagnostic Services: Dr. Essa Lab is committed to clinical excellence, utilizing stringent quality control protocols for all diagnostic procedures.
• Professional Reporting: Receive highly accurate, detailed audiogram reports interpreted by qualified specialists to guide your treatment pathway.
• Modern Diagnostic Approach: We utilize state-of-the-art, regularly calibrated diagnostic audiometers and soundproof testing cabins to ensure precise results.
• Comfortable Environment: Our diagnostic centers are designed to provide a welcoming, clean, and highly professional atmosphere for all visitors.
• Convenient Location: With an extensive network of branches across Karachi and other major cities, accessing quality diagnostic care is highly convenient.
• Commitment to Accurate Diagnosis: Backed by a legacy of trust spanning over five decades, Dr. Essa Lab is a household name for reliable diagnostic services in Pakistan.