Otolithiasis, the standard clinical name for benign paroxysmal positional vertigo, refers to transient vertigo and nystagmus that occurs when the head position is moved rapidly to a specific position, and is accompanied by nausea and vomiting in severe cases. It is the most common form of vertigo, accounting for about 20% to 40% of all outpatients with vertigo, with an annual incidence of 0.6% and a lifetime prevalence of 2.4%. Otoliths themselves are not life-threatening, but physical and mental health may be affected because patients are prone to falls and symptoms of anxiety and fear during vertigo attacks. In addition to its auditory function, the inner ear inside the human temporal bone also plays a role in maintaining the body’s balance, and it consists of two parts: the vestibule and the semicircular canal. The vestibular ellipsoid and balloon sacs have stone shaped calcium carbonate crystals (commonly known as “otoliths”) that can sense changes in linear acceleration and gravity. The three semicircular canals, which are at a 90° angle to each other, can sense changes in angular acceleration. If the otoliths in the vestibule are dislodged from their original position due to trauma or local structural degeneration and fall into the semicircular canals, vertigo will be caused when the patient’s head changes. Clinical manifestations of otolithiasis 1. vertigo induced by specific head position changes such as getting up, lying down, turning over, etc.; 2. vertigo lasts for a short period of time, usually less than 1 minute; 3. It is usually not accompanied by tinnitus and hearing loss. Otoliths can be divided into two categories, one is secondary, such as secondary to head trauma, vestibular neuritis, Meniere’s disease, etc.; the other is idiopathic, i.e., no clear secondary factors can be found. Investigations have shown that idiopathic otoliths are prone to occur in individuals with osteoporosis, hyperuricemia, and vitamin D deficiency in the body. Some patients have a family genetic predisposition. Otoliths are generally common in middle-aged and older women, but in recent years, there has been a trend towards a younger age. The ratio of men to women in our patients with otolithiasis is about 1:2, with an average age of 58 years, the oldest being 91 years old and the youngest being 22 years old. Treatment of otoliths If a patient’s vertigo attacks are consistent with the above symptoms, he or she needs to be further treated in the neurology or quintuplegia departments of major hospitals. However, there is still a lack of standardized otolithology treatment centers in Shanghai and even in China, and misdiagnosis and mistreatment often occur. For this reason, the Department of Neurology of the Ninth Hospital has opened a special outpatient clinic for vertigo (otolithiasis) since 2010, and has served more than 600 cases of otoliths so far, including many patients who came from other provinces and cities to seek treatment. For example, in horizontal hemimegalithiasis, vertigo is mainly induced when turning over to the left or right side, but it is worse when turning over to the side. In contrast, posterior hallux valgus usually presents with vertigo when lying back and when sitting up, and on examination, clockwise or counterclockwise torsional nystagmus can be detected. The traditional position-evoked test is mainly observed by the physician’s naked eye, which has a certain degree of error. The infrared video nystagmograph specially designed for otolith examination can clearly and objectively record the form and intensity of nystagmus, which is one of the most advanced instruments for otolithology examination in the world.