What is the Tullio phenomenon?

The Tullio phenomenon (TP) refers to sound-induced dizziness.

TP is not a disorder or disease – it is a symptom of an underlying condition.

People with TP experience disequilibrium (unsteadiness), vertigo, nausea and nystagmus (rapid involuntary eye movements). The symptoms are recurrent, brief and frequently triggered by certain types of noise or changes in middle ear pressure. Trigger sounds include loud sounds, high-pitched voices and sustained musical notes.

TP is named after Pietro Tullio, a biologist from Bologna, Italy, who first described it in 1929. Professor Tullio discovered that by drilling tiny holes in the semicircular canals of pigeons he could cause them to have balance problems when exposed to sound.

What causes TP?

TP arises from a thinning or dehiscence (hole) in the temporal bone overlying one of the semicircular canals. Until very recently it remained a mystery how sound waves could excite nerve signals in parts of the inner ear that normally only react to motion. It is now understood that sound waves entering the inner ear through a tiny hole in the temporal bone can cause an abnormal pumping of the fluid (endolymph) within the semicircular canals. The waves moving through the canals stimulate the hair cells that send signals to the brain about head movement. The brain misinterprets this information as head rotation. The brain reacts by sending signals to the eyes. They compensate by rotating in the opposite direction. A brief spinning sensation (vertigo) and nystagmus (rapid involuntary eye movements) is the result.

The opening in the temporal bone may stem from a congenital (present from birth) problem in the development of the inner ear, certain infectious diseases and/or from trauma. The majority of TP is associated with semicircular canal dehiscence (SCD). 90% of people with SCD confirmed by CT scanning of the temporal bones have symptoms when exposed to loud sounds.

TP is more rarely associated with other conditions including:

• otosclerosis
• congenital syphilis
• Ménière's disease
• perilymph fistula
• cholesteatoma with semicircular canal erosion and fenestration (opening)
• head trauma
• post stapedectomy (surgery to remove a small bone from the middle ear to improve hearing)
• post tympanomastoidectomy (surgery to treat frequent ear infections that have damaged the eardrum and tissue in and near the ear)
• collapsed canal syndrome
• congenital (present from birth) deafness
• Lyme disease
• middle ear osteoma (non-cancerous tumour)

Some people who experience TP have no associated medical condition. TP might, for example, be triggered by the noise of a loud explosion.

People with TP often also have pressure-induced dizziness and nystagmus (Hennebert's sign) as well as tinnitus and hearing loss.

Diagnosis of TP

An otolaryngologist (ENT) can often diagnose TP simply through a patient’s medical history and a focused examination. This can be confirmed by a high-resolution scan of the temporal bones to look for a hole or thinning and other ear problems. Sound sensitivity tests may also be done.

Treatment and management of TP

Treatment for milder cases of TP involve simple lifestyle changes, such as wearing earplugs. Surgery may be considered for some patients.

Sources

Iversen MM et al. Sound abnormally stimulates the vestibular system in canal dehiscence syndrome by generating pathological fluid-mechanical waves. Scientific Reports 8. 2018. Article number 10257. Available from: https://bit.ly/2LHDzPv

Kaski D, Davies R, Luxon L, Bronstein AM, Rudge P. The Tullio phenomenon: a neurologically neglected presentation. J Neurol. 2012 Jan. 259(1): 4-21. Available from: https://bit.ly/2XuiOOo

Lehmkuhl B, Andaloro C. Tullio phenomenon. StatPearls. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://bit.ly/2L8U47V