Dizziness is one of the most common complaints in outpatient clinics, and its etiology is complex and diverse involving neurology, otorhinolaryngology, general internal medicine and psychiatry. As a generalized subjective feeling, it is difficult to be determined by exact objective examination. Therefore, the correct diagnosis of dizziness relies more on the basic skills of clinicians, i.e., the correct determination of dizziness symptoms, the effective identification of the characteristics of clinical manifestations, the correct mastery of different causes of dizziness, and the correct use of various auxiliary examinations. A. Definition of dizziness symptoms is a prerequisite for correct diagnosis. The description of dizziness symptoms by patients may vary widely depending on culture, education, regional dialect and individual experience. When patients do have difficulty describing, a selective response may be used to determine symptom characteristics. Since 1972, it has been accepted in the medical community to classify dizziness into four distinct symptoms: vertigo, presyncope, imbalance, and a feeling of lightheadedness. Vertigo is a specific symptom that refers to the illusion or hallucination of motion with apparent rotation of surrounding objects or oneself, and the main cause is vestibular system dysfunction; presyncope is a transient feeling of “imminent loss of consciousness and fainting”, and the main cause is basically similar to syncope; imbalance is mainly a feeling of instability and loss of balance control when standing or walking. It is related to many kinds of neurological, medical and psychiatric diseases; the feeling of heavy head and light feet is the most non-specific, with the feeling of floating of head or body, or floating, and its causes are various. It can be seen that only by correctly defining the dizziness symptoms of vertigo or non-vertigo, clinicians can carry out further diagnosis and differential diagnosis, otherwise the whole diagnostic direction will be wrong. Second, careful questioning is the key to correct diagnosis Many clinical studies have proved that correct history taking is the key to clinical diagnosis. 90% of patients with symptoms of vertigo can be identified as specific vertigo or non-specific dizziness through questioning, and about 70-80% of patients with vertigo can also be clearly identified. During the interrogation, one should be particularly aware of the relevant clinical features, such as (1) form of onset: sudden onset is more likely to be a peripheral vestibular lesion, while chronic or subacute onset is more likely to be a central vestibular lesion. (2) Symptom level and accompanying autonomic symptoms: vertigo in peripheral vestibular lesions is mostly warmer and more often accompanied by obvious nausea and vomiting, while in central vestibular lesions it is mild and accompanied by mild or no autonomic symptoms. (3) Duration: benign episodic positional vertigo (BPPV) lasts for a few seconds, mostly less than 1 minute; Meniere’s disease, transient ischemic attacks and migraine-related vertigo last for minutes to hours; vestibular neuronitis and central lesions last for hours to days; and mental disorders last for weeks to months. The duration of symptoms due to different diseases is by no means fixed and is not the primary basis for diagnosis. (4) Frequency of attacks: single-onset vestibular neuronitis or vascular disease is the most common cause; Meniere’s disease or migraine should be considered first for recurrent vertigo; TIA should be considered for recurrent vertigo with other neurological manifestations; BPPV should be considered first for recurrent positional vertigo.(5) Concomitant symptoms: pay attention to the presence of tinnitus, tinnitus, ear pain, headache, hearing loss, facial palsy, imbalance, photophobia and phonophobia, nystagmus, and focal symptoms. and phonophobia, nystagmus, and focal neurological signs. (6) Triggering and relieving factors: head position changes are seen in BPPV, vestibular neuronitis, tumors, peripheral lymphatic leak, and multiple sclerosis; spontaneous vertigo is seen in vestibular neuronitis, stroke, tumors, migraine, Ménière’s disease, and multiple sclerosis; after upper respiratory tract infection is seen in vestibular neuronitis; stress is seen in psychogenic and migraine; and after ear pressure, trauma, or sustained exertion is seen in peripheral lymphatic leak. For nonspecific dizziness, special attention should be paid to the patient’s history of systemic diseases (hypertension, diabetes, various heart diseases, postural blood pressure fluctuations, medication use, anemia, thyroid disease, etc.), mental status (depression, anxiety, somatization disorders, etc.) and neurological diseases (deep sensory disorders, ataxia, multisystem degeneration, etc.). By mastering the clinical features of these different dizziness or vertigo and by careful and rigorous history questioning, clinicians can make a correct diagnosis for the majority of patients, which cannot be provided by any auxiliary examinations. Third, the mastery of different causes of dizziness is the guarantee of correct diagnosis Since the causes of dizziness involve various diseases such as neurology, otorhinolaryngology, general internal medicine and psychiatry, it is required that doctors of different specialties have multidisciplinary knowledge and can have the necessary mastery of multidisciplinary diseases involving vertigo or dizziness to reduce diagnostic errors. For example, by routinely performing the Dix-Hallpike test, a large number of patients with BPPV can be prevented from being misdiagnosed as cervical vertigo; by understanding that the so-called vertebrobasilar insufficiency of blood supply (VBI) is a TIA of the vertebrobasilar system, a large number of patients with long-term dizziness will not be misdiagnosed as VBI. Knowing which diseases are the most common causes of vertigo and which diseases are the most important causes of non-specific dizziness is the key to maintaining a busy clinical practice. Only then can we maintain clear diagnostic thinking and direction in busy clinical work, identify and diagnose diseases quickly, and avoid misdiagnosis, delayed diagnosis and overexamination due to inability to distinguish between common and rare diseases. Comparing the results of related studies at home and abroad, it can be seen that periventricular etiology and mental disorder etiology are the most important causes of dizziness, with the former being the primary cause of vertigo and the latter being the primary cause of nonspecific dizziness. In our country, the proportion of both is higher than foreign data because of the lack of a well-developed general medical system and the failure of a large number of patients with BPPV and psychotic dizziness to reach a timely and correct diagnosis, resulting in an exceptionally high proportion of them in specialized outpatient clinics in tertiary care hospitals. It can be seen that vestibular peripheral diseases (especially BPPV) are the most important etiology of vertigo, while mental disorder diseases and systemic diseases are the most important etiology of non-specific dizziness. IV. Targeted examination is the support for correct diagnosis Necessary physical examination should be performed in all patients. Although a complete physical examination cannot be carried out in an outpatient clinic, a targeted examination of vital signs, heart, cerebral nerves, ataxia, deep sensation, and hearing should be performed. Dix-Hallpike test should be done in all patients with vertigo or with posture-related dizziness, and immediate results can be obtained by performing manual repositioning in those who are sure. Vestibular function and pure tone measurements should be performed in patients with possible peripheral vestibular lesions. Neuroimaging should be performed for suspected central vestibular lesions, and MRI or CT is particularly recommended because CT is extremely difficult to detect various posterior cranial fossa lesions due to bone interference. On the contrary, indiscriminate vestibular function or neuroimaging not only cannot help the diagnosis, but can confuse the diagnostic thinking and lead to misdiagnosis. Studies have demonstrated no significant difference in the results of MRI, audiometry, and vestibular function tests between indiscriminate dizziness patients and age-matched normal subjects, with a positive test rate of less than l%. The root cause of many clinical errors in diagnosis is precisely the lack of proper diagnosis and over-reliance on ancillary tests, as well as a lack of understanding of the specificity and limitations of various ancillary tests. For example, the Dix-Hallpike test is not performed in patients with BPPV, but a large number of cervical spine imaging examinations are performed, and then the degenerative changes of the cervical spine, which are common in the middle-aged and elderly population, are used to explain vertigo, and the diagnosis of cervical spondylosis or cervical vertigo is taken for granted. Then, for example, we do not seriously understand the depression and anxiety status of patients with mental disorder dizziness, but carry out cranial CT, MRI or transcranial Doppler ultrasonography, and then use white matter lesions or cavernous infarcts seen in imaging and common in the elderly population to explain vertigo, or even diagnose it as VBI arbitrarily. V. Focusing on updating knowledge is the source of correct diagnosis Although there are many patients with dizziness and vertigo, there are still a considerable number of Although there are many patients with dizziness and vertigo, there are still a considerable number of patients who cannot get the correct diagnosis in time, and some of them cannot be diagnosed for a long time. Therefore, on the one hand, clinicians should diagnose the symptoms in a scientific and realistic manner, and should not make the diagnosis of VBI or cervical vertigo arbitrarily, and on the other hand, they should actively study and update their knowledge to improve the diagnosis of dizziness. With the progress of research on the etiology of dizziness, related concepts and diagnoses have changed significantly and deserve attention. As the awareness of BPPV has improved, its diagnosis rate has increased significantly and it has become the first cause of dizziness. For example, 10 years ago, many doctors did not know about BPPV and few doctors (especially non-otologists) diagnosed the disease, but since neurologists learned to diagnose it, many doctors can diagnose hundreds of patients. This is not an indication that the disease is endemic in our country, but simply a reflection of our long-standing lack of awareness of the disease. Previously, it has been found that paroxysmal vertigo in childhood is associated with migraine, and it has also been found that migraine patients can present with vertigo rather than headache in old age, and it is called migraine equilibrium, but the relationship between vertigo and migraine is not well understood. Recent studies have found that about 30% of dizziness patients have a history of migraine, and about 30% of migraine patients also have dizziness or vertigo, and the correlation between the two far exceeds the correlation with other diseases or syndromes. The prevalence of motion sickness is nine times higher in migraineurs than in the general population. What used to be called benign episodic vertigo or vestibular Meniere’s disease (without accompanying auditory or neurological symptoms) was also considered to be migraine. As the diagnostic criteria for migrainous vertigo have been promoted, more and more patients are being identified. Some traditional recognition and diagnostic concepts, on the other hand, have been considered wrong or ambiguous due to the progress of etiological studies and have been eliminated. For example, China has long diagnosed a large number of middle-aged and elderly people with chronic dizziness or vertigo as VBI and taken for granted that VBl is a state that is not normal but does not meet the criteria of ischemia, but the international classification of ischemic cerebrovascular diseases and the International Classification of Diseases do not have VBI, and the expert consensus in China also suggests that VBI is 11A of the posterior circulatory system and never a separate and specific disease. We hope that doctors will actively study and eliminate this “garbage can” diagnosis as soon as possible. Cervical vertigo is also used by many physicians, but there is a lack of serious clinical research on the accuracy of this diagnosis and the reliability of the diagnostic criteria, and many of them use hypothesis instead of clinical evidence or even against the evidence. In fact, there are many etiologies of dizziness or vertigo caused by turning the neck, and almost all kinds of vertigo disorders are aggravated by turning the head and neck. Turning the neck almost invariably causes a head turn at the same time, and visual and vestibular sensory stimulation cannot be excluded. The vertigo (more often dizziness and unsteadiness) during neck turning is associated with abnormalities of deep sensation caused by neck disorders (myofascial inflammation), and the current studies on cervical vertigo all suffer from weaknesses such as unverifiable diagnosis, lack of specific diagnostic methods, and inability to explain the large number of clinical inconsistencies, so this vague definition and diagnosis is no longer recommended internationally.