Auditory Brainstem Response — MCQs
Where will be the placement location for Auditory Brainstem Implant?
Which of the following conditions is NOT typically associated with increased REM latency?
Progressive loss of hearing, tinnitus and ataxia are commonly seen in a case of -
Site for placing an electrode in auditory brain stem implant is?
Wave II in BERA originates from ?
Which of the following tests is used to differentiate between cochlear and retrocochlear hearing loss?
A child who was treated for H. influenzae meningitis is being discharged. Most important investigation to be done before discharge is:
In infants, what is the most sensitive audiometric screening method?
In infants most sensitive audiometric screening is
To distinguish between cochlear and post-cochlear damage, which test is done?
Auditory Brainstem Response Indian Medical PG Practice Questions and MCQs
Question 1: Where will be the placement location for Auditory Brainstem Implant?
- A. Scala tympani
- B. Recess of 4th ventricle (Correct Answer)
- C. IAC
- D. Back of ear
Explanation: ***Recess of 4th ventricle*** - An **Auditory Brainstem Implant (ABI)** is placed on the **cochlear nucleus** in the brainstem, which is anatomically located near the **lateral recess of the fourth ventricle**. - The implant stimulates these nuclei directly, bypassing the damaged auditory nerve in patients who cannot benefit from cochlear implants. *Scala tympani* - The **scala tympani** is the location for electrode placement in a **cochlear implant**, not an auditory brainstem implant. - Cochlear implants stimulate the intact auditory nerve within the cochlea. *IAC* - The **internal auditory canal (IAC)** houses the auditory and facial nerves, but it is not the target site for an ABI. - The ABI is designed for patients whose auditory nerve (which passes through the IAC) is non-functional. *Back of ear* - The "back of the ear" is the general area where the **external processor of a cochlear implant** or a **bone-anchored hearing aid** is typically worn, not the surgical placement site for an ABI. - The ABI's internal component is surgically placed within the cranium.
Question 2: Which of the following conditions is NOT typically associated with increased REM latency?
- A. First night effect
- B. SSRIs
- C. Restless leg syndrome
- D. Narcolepsy (Correct Answer)
Explanation: ***Narcolepsy*** - **Narcolepsy** is characterized by pathologically **decreased REM latency**, not increased. - Patients typically enter REM sleep within **15 minutes** of sleep onset (normal is 60-90 minutes). - **Sleep-onset REM periods (SOREMPs)** are a diagnostic hallmark of narcolepsy, seen on multiple sleep latency testing (MSLT). - Since narcolepsy is associated with *decreased* REM latency, it is definitively **NOT associated with increased REM latency**, making it the correct answer to this negation question. *First night effect* - The **first-night effect** refers to sleep disruption and increased REM latency during the first night of polysomnography in an unfamiliar environment. - This is a well-documented phenomenon that **increases REM latency** due to environmental stress and arousal. *SSRIs* - **Selective serotonin reuptake inhibitors (SSRIs)** significantly suppress REM sleep, leading to **increased REM latency** and decreased total REM sleep time. - This effect is mediated by increased serotonin, which inhibits cholinergic neurons involved in REM sleep generation. - SSRIs can increase REM latency by 30-90 minutes beyond normal values. *Restless leg syndrome* - **Restless leg syndrome (RLS)** primarily causes difficulty initiating sleep and sleep fragmentation due to uncomfortable leg sensations. - While RLS disrupts sleep architecture, its effect on REM latency is **variable and inconsistent** - some studies show minimal impact, while chronic sleep deprivation from RLS may actually decrease REM latency during rebound sleep. - However, RLS is not as clearly and consistently dissociated from increased REM latency as narcolepsy is.
Question 3: Progressive loss of hearing, tinnitus and ataxia are commonly seen in a case of -
- A. Acoustic neuroma (Correct Answer)
- B. Otitis media
- C. Ependymoma
- D. Cerebral glioma
Explanation: ***Acoustic neuroma*** - This benign tumor arises from the **vestibulocochlear nerve (cranial nerve VIII)**, leading to **progressive unilateral hearing loss**, **tinnitus**, and **ataxia** as it compresses the adjacent cerebellum [1]. - The symptoms are progressive and often insidious, reflecting the slow growth of the tumor, and are highly characteristic for this condition [1]. *Otitis media* - **Otitis media** is an **inflammation/infection of the middle ear**, primarily causing ear pain, ear discharge, and conductive hearing loss. - While it causes hearing loss, it typically presents with acute symptoms and does not typically cause **tinnitus** or **ataxia** unless there are severe complications affecting the inner ear or brain. *Ependymoma* - **Ependymomas** are tumors originating from the **ependymal cells** lining the ventricles and spinal cord, often causing symptoms related to increased intracranial pressure (headache, nausea) or spinal cord compression. - They do not typically present with the specific triad of **progressive hearing loss**, **tinnitus**, and **ataxia** characteristic of acoustic neuroma. *Cerebral glioma* - **Cerebral gliomas** are brain tumors that arise from glial cells and present with a wide range of neurological symptoms depending on their location, such as **seizures**, **weakness**, or **cognitive changes**. - They are unlikely to present with the specific combination of **progressive hearing loss**, **tinnitus**, and **ataxia** unless located in the brainstem or cerebellum in a way that specifically compresses the eighth cranial nerve and cerebellar pathways, which is less common than for an acoustic neuroma.
Question 4: Site for placing an electrode in auditory brain stem implant is?
- A. Round window
- B. Sinus tympani
- C. Lateral ventricle
- D. Recess of fourth ventricle (Correct Answer)
Explanation: ***Recess of fourth ventricle*** - The auditory brainstem implant (ABI) electrode arrays are typically placed on the surface of the **cochlear nucleus**, which lies in the **lateral recess of the fourth ventricle and cerebellopontine angle**. - This placement allows direct stimulation of the central auditory pathways, bypassing a damaged or absent auditory nerve. *Round window* - The round window is the site for electrode placement in a **cochlear implant**, not an auditory brainstem implant. - A cochlear implant stimulates the **auditory nerve terminals** within the cochlea. *Sinus tympani* - The sinus tympani is an **anatomical space** within the middle ear. - It is not a site for implant electrode placement for either cochlear or brainstem implants. *Lateral ventricle* - The lateral ventricles are spaces within the brain that contain **cerebrospinal fluid** and are not directly involved in the auditory pathway for implant stimulation. - Implants for hearing are generally directed towards the auditory neural structures.
Question 5: Wave II in BERA originates from ?
- A. Cochlear nucleus
- B. Distal eighth nerve
- C. Lateral lemniscus
- D. Proximal eighth nerve (Correct Answer)
Explanation: ***Proximal eighth nerve*** - **Wave II** of the **Brainstem Auditory Evoked Response (BAER)**, or BERA, is generated by the **proximal portion of the auditory (eighth cranial) nerve** as it enters the brainstem. - This wave reflects the electrical activity of the auditory nerve fibers just before they synapse in the cochlear nucleus. *Cochlear nucleus* - The **cochlear nucleus** is primarily associated with the generation of **Wave III** of the BERA, following the auditory nerve activity. - It's the first synapse in the central auditory pathway, processing signals from the auditory nerve. *Distal eighth nerve* - The **distal portion of the eighth cranial nerve** is where **Wave I** of the BERA originates, representing the initial compound action potential from the auditory nerve as it exits the cochlea. - This wave reflects the activity closest to the cochlea, preceding the more central brainstem responses. *Lateral lemniscus* - The **lateral lemniscus** is a major ascending auditory pathway in the brainstem, and its activity contributes to later waves, specifically **Wave V or VI**, which are generated from the more rostral brainstem structures. - It plays a role in transmitting auditory information from the cochlear nuclei and superior olivary complex to the inferior colliculus.
Question 6: Which of the following tests is used to differentiate between cochlear and retrocochlear hearing loss?
- A. Recruitment
- B. Threshold tone decay test
- C. Evoked response audiometry (Correct Answer)
- D. SISI test
Explanation: **Evoked response audiometry** - **Evoked response audiometry (ERA)**, specifically **Auditory Brainstem Response (ABR)** or **Brainstem Evoked Response Audiometry (BERA)**, is the gold standard for differentiating between cochlear and retrocochlear hearing loss. - ABR measures electrical activity from the auditory nerve and brainstem in response to sound, allowing for differentiation between **cochlear pathology** (normal ABR latencies with hearing loss) and **retrocochlear pathology** (prolonged interpeak latencies, absent waves, or abnormal waveform morphology suggestive of auditory nerve or brainstem lesion). - Classic findings in retrocochlear lesions include prolonged I-V interpeak latency or absent Wave V. *SISI test* - The **Short Increment Sensitivity Index (SISI) test** assesses the ability to detect small (1 dB) increments in sound intensity superimposed on a continuous tone. - A **high SISI score (>70%)** indicates **cochlear dysfunction** due to recruitment phenomenon, while a **low score (<20%)** may suggest retrocochlear pathology. - However, it does not directly differentiate between cochlear and retrocochlear lesions with the same specificity and sensitivity as ABR. *Threshold tone decay test* - The **Tone Decay Test (TDT)** measures the ability to sustain the perception of a continuous pure tone presented at or near threshold level. - **Significant tone decay (>30 dB in 60 seconds)** suggests **retrocochlear pathology** due to auditory nerve fatigue, making it useful for screening. - While helpful, it is less precise, sensitive, and specific than ABR for definitive differentiation and may have false positives. *Recruitment* - **Recruitment** is an abnormal growth in the perception of loudness, where a small increase in sound intensity leads to a disproportionately large increase in perceived loudness. - It is a classic sign of **cochlear hearing loss**, particularly associated with outer hair cell damage (sensory hearing loss). - Its presence confirms cochlear pathology but its absence does not confirm retrocochlear lesions, making it less reliable as a differentiating test compared to ABR.
Question 7: A child who was treated for H. influenzae meningitis is being discharged. Most important investigation to be done before discharge is:
- A. Brainstem evoked auditory response (Correct Answer)
- B. Growth screening test
- C. Psychotherapy
- D. MRI
Explanation: ***Brainstem evoked auditory response*** - **Sensorineural hearing loss** is a common and severe complication of *H. influenzae* meningitis, occurring in about 5-30% of cases due to damage to the auditory nerve or cochlea. - **Brainstem Evoked Auditory Response (BAER)** is an objective test that measures the electrical activity in the auditory pathway from the cochlea to the brainstem, making it the most reliable method for detecting hearing impairment in infants and children. *Growth screening test* - While chronic illness can affect growth, **growth faltering** is not specific to *H. influenzae* meningitis or its sequelae in the acute or subacute phase. - Growth checks are part of routine pediatric care and would be performed but are not the *most important* specific investigation for meningitis complications before discharge. *Psychotherapy* - **Psychotherapy** is a treatment modality for psychological and behavioral issues, not a diagnostic test. - It would only be considered if the child developed significant emotional or behavioral problems after meningitis, and these are typically assessed through clinical observation and neurodevelopmental screening, not a direct "psychotherapy" investigation. *MRI* - **MRI** is primarily used to detect structural brain abnormalities such as **hydrocephalus**, **subdural effusions**, **cerebral edema**, or **infarcts** that may result from meningitis. - While important for assessing neurological damage, **hearing loss** is a distinct and prevalent complication that requires a specific functional assessment (BAER), which MRI does not provide.
Question 8: In infants, what is the most sensitive audiometric screening method?
- A. Electrocochleography
- B. BERA (Correct Answer)
- C. Tympanometry
- D. Cochlear evoked response
Explanation: ***BERA*** - **Brainstem Evoked Response Audiometry (BERA)** is widely considered the most sensitive audiometric screening method for infants because it directly measures the electrical activity of the auditory pathway from the cochlea to the brainstem. - It can identify hearing loss even in unresponsive infants or those who cannot cooperate with behavioral audiometry. *Electrocochleography* - **Electrocochleography (ECoG)** measures electrical potentials generated by the cochlea and auditory nerve. - While very specific for Ménière's disease and assessing cochlear function, it is generally less commonly used as a primary screening tool for general hearing loss in infants compared to BERA due to its more invasive nature (requiring an electrode near the tympanic membrane). *Cochlear evoked response* - This term is somewhat general and can refer to several tests, including **otoacoustic emissions (OAEs)** or the initial parts of BERA. - While OAEs are a good screening tool to assess outer hair cell function, they are not as comprehensive as BERA in evaluating the entire auditory pathway and can miss neural hearing loss. *Tympanometry* - **Tympanometry** assesses the function of the middle ear, including the eardrum and ossicles. - It is crucial for detecting middle ear pathologies like **otitis media with effusion**, but it does not directly measure auditory nerve or brainstem responses to sound and is not a measure of hearing threshold.
Question 9: In infants most sensitive audiometric screening is
- A. Electrocochleography
- B. Cortical evoked response
- C. Tympanometry
- D. BERA (Correct Answer)
Explanation: ***BERA (Brainstem Evoked Response Audiometry)*** - **Most sensitive and objective** audiometric test for infants, as it measures electrical activity in the brainstem in response to sound, **independent of cooperation** - Can be performed on **sleeping or sedated infants**, making it ideal for newborn screening - Effectively identifies **sensorineural hearing loss** in newborns and young children, crucial for early intervention - Gold standard for **Universal Newborn Hearing Screening (UNHS)** programs worldwide *Electrocochleography* - Assesses electrical potentials generated by the **cochlea and auditory nerve** - While sensitive, it is more **invasive** and primarily used for diagnosing conditions like **Ménière's disease** or identifying auditory neuropathy - Not typically used as a primary infant screening tool *Cortical evoked response* - Measures activity in the **auditory cortex**, making it more susceptible to **sleep states, sedation, and cortical maturation** - Limited reliability for routine infant screening due to developmental variability - Typically used for older children or to assess higher-level auditory processing *Tympanometry* - Assesses **middle ear function** and mobility of the eardrum - Primarily used to detect **middle ear effusions** or ossicular chain problems - Does **not evaluate hearing threshold** or cochlear/auditory nerve function, therefore not suitable for hearing sensitivity screening
Question 10: To distinguish between cochlear and post-cochlear damage, which test is done?
- A. Auditory brainstem response (ABR) (Correct Answer)
- B. Impedance audiometry
- C. Pure tone audiometry
- D. Electrocochleography (ECochG)
Explanation: ***Auditory brainstem response (ABR)*** - This test evaluates the integrity of the **auditory pathway from the cochlea through the brainstem**, making it excellent for differentiating between cochlear (sensory) and post-cochlear (retrocochlear/neural) lesions. - Abnormalities in wave latencies or interpeak intervals suggest **retrocochlear pathology** (e.g., acoustic neuroma), while normal ABR responses despite hearing loss point towards cochlear damage. - ABR records **five characteristic waves (I-V)** representing neural transmission from the auditory nerve through the brainstem. *Impedance audiometry* - Primarily assesses the **middle ear function**, including the eardrum and ossicles, by measuring **tympanic membrane compliance** and **acoustic reflexes**. - It does not directly evaluate the function of the **cochlea or the retrocochlear pathways**, making it unsuitable for this differentiation. *Pure tone audiometry* - Measures a person's **hearing sensitivity** at different frequencies and provides information on the **degree and type of hearing loss (conductive, sensorineural, or mixed)**. - While it identifies sensorineural hearing loss, it cannot pinpoint whether the damage is **cochlear or retrocochlear** within the sensorineural category. *Electrocochleography (ECochG)* - Records **electrical potentials generated by the cochlea and auditory nerve** in response to sound, including **cochlear microphonics, summating potentials, and compound action potentials**. - While it evaluates cochlear function and is useful in diagnosing **Meniere's disease** and **auditory neuropathy**, it does not adequately assess the **integrity of the brainstem auditory pathways** needed to differentiate retrocochlear lesions.
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