Hearing and Balance Problems after Head Injury

Definition and epidemiology

Hearing and balance problems after head injury include dizziness, unsteadiness, hearing loss, tinnitus, reduced sound tolerance and auditory processing complaints that appear after the impact. This entry focuses on situations in which there is no temporal bone fracture or the fracture is not the main issue; fracture-related problems are described under temporal bone fractures. Mild traumatic brain injury (concussion) is the commonest setting for these symptoms. In sport-related concussion, symptoms lasting more than four weeks are defined as ‘persisting symptoms’, while unrestricted return to sport usually occurs within a month (Patricios et al., 2023).

Dizziness and imbalance are among the commonest complaints after concussion and last six months or longer in some patients (Akin et al., 2017). Balance problems after mild head injury have been reported in 15-78% of patients, depending on the study, and in one long-term follow-up of untreated mild head injury, vertigo persisted in 59% after five years (Fausti et al., 2009). In military populations, blasts are a leading cause of traumatic brain injury. Hearing loss and tinnitus are the two most prevalent service-connected disabilities among US veterans of the Iraq and Afghanistan wars (Theodoroff et al., 2015), and they affect up to 60% of patients with blast-related traumatic brain injury (Fausti et al., 2009).

Symptoms and signs

Dizziness after concussion takes several forms: a spinning sensation triggered by head movement and lasting seconds, constant swaying or unsteadiness, dizziness that worsens in crowded or visually busy places, attacks accompanied by headache, and light-headedness linked to neck pain. Nausea, poor concentration, sensitivity to light and sound, fatigue and disturbed sleep are common companions. Some patients with persistent dizziness and motion sensitivity but no inner ear cause have features of vestibular migraine (Fife and Kalra, 2015). In others, the initial vestibular problem settles but Persistent Postural-Perceptual Dizziness (PPPD) develops.

Hearing complaints vary as well. Labyrinthine concussion causes sudden sensorineural hearing loss and vertigo at the time of injury, and the symptoms are often short-lived (Kurihara et al., 2020). Eardrum perforation has been reported in 4-79% of people exposed to blasts, and many patients say they struggle to follow speech in noise despite normal hearing thresholds (Fausti et al., 2009). Tinnitus, finding sounds uncomfortably loud and tiring quickly when listening are also frequently described. In children and adolescents these problems may show up as difficulty following lessons and a fall in school performance.

Causes and risk factors

Benign paroxysmal positional vertigo heads the list of peripheral causes: the impact dislodges otoconia from the utricle and the debris enters the semicircular canals. BPPV has been reported in 10-25% of people after head trauma (Fausti et al., 2009). Of 192 patients presenting with positional vertigo after head injury, 32 had confirmed BPPV, and traumatic BPPV needed more treatment sessions than idiopathic BPPV (Ahn et al., 2011). There is some evidence that the otolith organs may be more vulnerable to impact and blast than the horizontal semicircular canal (Akin et al., 2017). Labyrinthine concussion is injury to the membranous labyrinth without a fracture, and inner ear haemorrhage may be visible on MRI (Kurihara et al., 2020); rupture of the oval or round window can cause a perilymph fistula.

Central causes include diffuse axonal injury, white matter abnormalities and damage to central vestibular structures (Akin et al., 2017). The same mechanisms can affect the auditory pathways: blast-exposed veterans with largely normal hearing thresholds have shown more abnormal results on central auditory processing tests than controls (Gallun et al., 2012). In blast injury, the pressure wave itself, the intense accompanying noise and acceleration of the head act together; in adults a pressure of about 5 psi ruptures half of eardrums (Fausti et al., 2009). Neck injury, anxiety, depressive symptoms and post-traumatic stress disorder can maintain or aggravate dizziness (Fife and Kalra, 2015).

Audiological and clinical assessment

The first step is to rule out emergencies. The type of complaint is then explored in detail: whether the dizziness is spinning or unsteadiness, whether it is triggered by head movement or visual stimuli, how long it lasts, and whether headache or neck pain accompanies it. The concussion consensus statement includes vestibular-ocular motor screening in the office assessment and recommends checking for symptom provocation with vestibulo-ocular reflex and oculomotor tests when monitoring recovery (Patricios et al., 2023).

• Positional tests: the Dix-Hallpike and supine roll tests should be performed in every patient. Traumatic BPPV can involve more than one canal; in one series, 24 of 32 patients had posterior and 11 had horizontal canal involvement (Ahn et al., 2011).
• Vestibular test battery: the video head impulse test (vHIT), caloric testing, cervical and ocular vestibular evoked myogenic potentials (VEMP), oculomotor tests such as saccades and smooth pursuit, and posturography help to separate peripheral from central involvement. VEMPs are particularly useful for detecting otolith involvement (Akin et al., 2017).
• Audiological assessment: otoscopy, air- and bone-conduction thresholds, tympanometry, ipsilateral and contralateral acoustic reflexes, speech thresholds and monosyllabic word recognition form the core battery; ABR and OAEs are used when behavioural testing is unreliable (Fausti et al., 2009).
• Central auditory processing tests: temporal processing, dichotic listening, low-redundancy speech and binaural interaction tests, together with middle and late latency responses, can show the origin of the complaint; no standard battery exists for these patients (Fausti et al., 2009). See central auditory processing disorder for details.
• Sound tolerance: loudness discomfort levels and questionnaires document the degree of decreased sound tolerance and track it over time.
• Questionnaires and imaging: the Dizziness Handicap Inventory and hearing handicap scales show the impact on daily life (Fausti et al., 2009). In sudden sensorineural loss or unexplained vertigo, MRI may reveal inner ear haemorrhage (Kurihara et al., 2020).

The differential diagnosis is usually less about finding a single cause than about weighing the contribution of several. Peripheral problems such as BPPV and labyrinthine concussion, vestibular migraine features, neck-related symptoms and psychological factors can coexist in the same patient, so assessment calls for ENT, neurology, audiology and physiotherapy to work together (Fife and Kalra, 2015).

Treatment and audiological rehabilitation

Post-traumatic BPPV responds well to canalith repositioning (Akin et al., 2017). More sessions may be needed than in idiopathic BPPV, but recurrence rates are similar (15.6% in traumatic and 18.8% in idiopathic cases) (Ahn et al., 2011). For vestibular disorders other than BPPV, vestibular rehabilitation is the mainstay of treatment, combined with other rehabilitation methods and medication when needed (Akin et al., 2017). The physical therapy guideline likewise recommends vestibular rehabilitation for patients with dizziness and vestibulo-oculomotor dysfunction after concussion (Quatman-Yates et al., 2020). If dizziness, neck pain or headache lasts more than ten days, cervicovestibular rehabilitation is recommended, as is subsymptom-threshold aerobic exercise within 2-10 days of injury (Patricios et al., 2023).

Patients with features of vestibular migraine may benefit from migraine-preventive treatment (Fife and Kalra, 2015); the choice of medication rests with the doctor. Sudden hearing loss due to labyrinthine concussion should be assessed by an ENT doctor without delay, as for any sudden sensorineural hearing loss. Persistent hearing loss is managed with hearing aids. For patients with normal thresholds who struggle in noise, adjusting the listening environment, communication strategies, remote microphone systems and auditory training can be used, although evidence for their effectiveness is limited. Tinnitus and sound tolerance problems are managed with counselling and sound therapy; avoiding sound and wearing earplugs all the time are discouraged because they can further reduce tolerance.

Patients and families should be told clearly when to seek emergency care. Loss or clouding of consciousness, seizures, behavioural change and marked unsteadiness are signs that require an athlete to be removed from play immediately (Patricios et al., 2023). Clear fluid from the ear or nose, bleeding from the ear, sudden hearing loss and facial palsy suggest a temporal bone fracture and need urgent assessment.

Impact on quality of life and advice

Patients without a visible injury often say that those around them do not understand symptoms such as dizziness, sound sensitivity or difficulty hearing in noise. These problems make it harder to return to work or school and can lead to avoiding social situations and increasing anxiety. After sport-related concussion, 93% of athletes returned to learning without academic support within ten days (Patricios et al., 2023); those with persisting symptoms need a graded return and temporary adjustments at school or work.

Practical advice: after the first few days, do not stay completely inactive; return gradually to activity at the level your doctor recommends. If dizziness persists, check with your doctor before driving or working at heights. Sitting near the front in class, choosing a seat away from noise in meetings and taking short breaks from demanding listening reduce listening effort. If sounds bother you, use earplugs only in genuinely noisy places. If you are exposed to military or occupational noise, wear hearing protection consistently and keep up with hearing checks. Tell your audiologist about your symptoms and the situations you find hardest; the rehabilitation plan is built on this information.