Conductive and Sensorineural: Two Ways Hearing Can Break Down

Two people can describe muffled hearing for different reasons. One may have reduced sound transfer, another cochlear or nerve dysfunction, and some people have both.

Hearing loss can involve different pathway components Hearing depends on sound transfer, cochlear conversion, auditory nerve transmission and brain processing. A difficulty at one stage can resemble a difficulty at another. Pure tone hearing loss is commonly classified as conductive, sensorineural or mixed. These labels describe the affected pathway component rather than the exact disease causing it. Some listening difficulties arise from brain processing even when pure tone thresholds appear normal. Those problems do not fit neatly into these three threshold patterns. Conductive hearing loss reduces sound transfer Conductive hearing loss occurs when the outer or middle ear does not transfer sound efficiently towards the cochlea. The cochlea may still function normally. Possible causes include earwax, an eardrum perforation, middle ear fluid or reduced ossicle movement. Different causes affect frequencies and severity in different ways. Conductive loss often makes sounds quieter, but it is not only a volume control. Greater loss can also make speech difficult, especially in background noise. Some conductive causes are temporary or treatable. Others are longstanding, recur or cannot be fully corrected. Sensorineural hearing loss affects sensory or nerve function Sensorineural hearing loss involves the cochlea, its sensory hair cells or the auditory nerve. Age, harmful noise, medicines, illness and inherited factors can contribute. It can reduce hearing sensitivity and frequency resolution. Some people notice reduced clarity, particularly when several people speak or background noise is present. Sensorineural loss may be gradual, sudden, stable, progressive or fluctuating. Many common cochlear losses are permanent, but sensorineural loss is not automatically irreversible. Sudden sensorineural hearing loss can recover partly or completely in some people. It can also remain permanent, so prompt assessment matters. Mixed hearing loss combines both components Mixed hearing loss means that conductive and sensorineural components affect the same ear. For example, earwax can occur alongside age related cochlear hearing loss. Treating the conductive component may improve hearing. A remaining sensorineural component may still require hearing support. The amount of improvement cannot be predicted from the label alone. It depends on each component's cause, severity and available treatment. Pure tone audiometry measures hearing thresholds Pure tone audiometry measures the quietest tones detected at several frequencies. The results are plotted on an audiogram for each ear. Air conduction sends sound through the ear canal, eardrum, ossicles, cochlea and auditory pathway. It tests the complete route but does not locate a problem alone. Bone conduction sends skull vibration towards the cochleae and largely bypasses the outer and middle ear. It still depends on cochlear and neural function. Bone conducted sound can reach both cochleae. Audiologists use masking when needed so the non test ear does not provide the response. The air bone gap supports classification An air bone gap occurs when air conduction thresholds are poorer than bone conduction thresholds at the same frequencies. A reliable gap supports a conductive component. Raised air thresholds with bone thresholds in the expected range support conductive hearing loss. Raised air and bone thresholds without a significant gap support sensorineural hearing loss. Raised bone thresholds with an additional air bone gap support mixed hearing loss. These patterns classify components but do not identify the exact cause. Small or isolated gaps can arise from measurement limits or testing conditions. Audiologists consider masking, reliability, frequency pattern and the wider assessment. Other hearing tests answer different questions Otoscopy allows looking at the ear canal and eardrum. It can identify visible wax or a perforation but cannot show the cochlea or auditory nerve. A normal looking eardrum does not exclude every conductive problem. Some ossicle or middle ear conditions can exist without an obvious surface abnormality. Tympanometry measures eardrum and middle ear movement as ear canal pressure changes. It does not directly measure the quietest sound someone can hear. Speech recognition testing measures how accurately selected speech is repeated under controlled conditions. It cannot fully predict conversation in every real world environment. Tuning fork tests provide rapid screening clues about a possible conductive component. They do not replace formal audiometry and can miss mild, bilateral or mixed patterns. Treatment depends on cause and communication needs Conductive management may include wax removal, treatment of infection, monitoring, surgery or a hearing device. The correct option depends on the underlying condition. Hearing aids amplify sound and can help many people with sensorineural, mixed or selected conductive hearing loss. They do not restore normal cochlear processing. Assistive listening devices and communication strategies can also improve daily function. Selected people with severe hearing loss may benefit from a cochlear implant. A cochlear implant bypasses damaged inner ear structures and stimulates the auditory nerve. It does not recreate normal hearing and requires specialist assessment and rehabilitation. Know when urgent assessment matters Ask for an urgent GP appointment or contact NHS 111 immediately for sudden hearing loss in one or both ears. Do not delay while treating possible earwax yourself. Hearing that worsens over several days or weeks also needs urgent advice. The same applies when hearing loss occurs with earache or ear discharge. Call 999 for sudden hearing change with facial weakness, arm weakness, speech difficulty, severe new difficulty walking or collapse. Do not drive yourself. Arrange assessment for gradual hearing loss, persistent one sided hearing difference or continuing hearing difficulty after wax or infection treatment.

Conductive and sensorineural components describe different parts of the hearing pathway. Mixed loss combines both, while test patterns guide classification without proving the cause or outcome.