Dizziness is the second most common symptom in neurology (headache is the first). The incidence of dizziness increases with age, with a high prevalence in the elderly population and the number one reason for medical consultation in people over 65 years of age. Dizziness has a variety of causes and manifestations, and there are no objective tests that can reliably diagnose and differentially diagnose various types of dizziness. Dizziness (dizzy) definition: Dizziness is a group of generalized, non-specific symptoms, including: 1, vertigo surrounding objects or their own apparently rotating illusion of motion or hallucination 2, pre-syncope: a transient, immediately unconscious, fainting sensation 3, imbalance: unstable or insecure feeling, no rotation, difficulty standing and walking 4, head heavy feeling: head or environment with “swimming “, floating, dizzy or swaying sensation. In terms of symptomatology, vertigo is specific, suggesting damage to the vestibular system. History of dizziness: Dizziness is felt subjectively and lacks objective circumstantial evidence, so one’s own description becomes the most important basis for diagnosis. However, many patients do not or do not take the accurate description of their symptoms seriously. The significance of careful history taking is that it can distinguish between more than 90% of symptoms that are vertigo or non-vertigo dizziness and can clarify the etiology of 70% to 80% of dizziness. Correctly guide and ask about the symptoms: “Do you feel as if you are about to faint?” Cue pre-syncope. “Do you feel unstable when walking or sitting?” Cue imbalance. “Do you feel nervous or like something bad is about to happen?” Cues mental nature. “Do you feel like your surroundings are spinning?” Prompts vertigo. After identifying the symptoms as vertigo, ask carefully about: the severity of vertigo, duration, number and frequency of episodes, precipitating factors, and other medical history , vertigo, vomiting, nystagmus, and unsteadiness in standing are seen in all types of vertigo. Pay attention to the accompanying autonomic nervous system symptoms such as nausea and vomiting, and pay special attention to the presence of neurological or cochlear symptoms. When other neurological symptoms are present and the common peripheral causes are excluded, a central lesion should be considered. If there are no neurological symptoms but cochlear symptoms such as tinnitus and deafness, then peripheral pathology should be considered first. For non-vertigo dizziness, attention should be paid to inquiring about the patient’s systemic diseases, medications taken, and mental status. Examination of patients with dizziness: Basic systemic examination, neurological and otologic examination is important. Dix-Hallpike examination should be routinely performed in patients with vertigo in order to rapidly identify the most common causes of vertigo. In patients with peripheral vestibular lesions, attention should be paid to the targeted examination of vestibular function, etc., while in patients with central vestibular lesions, attention should be paid to the relevant imaging examinations. Many studies have demonstrated that MRI, audiometry, and vestibular function tests do not differ significantly between unselected patients with dizziness and age-matched normal subjects, with a positive rate of less than 1%, and therefore various ancillary tests are not recommended for unselected patients with dizziness. The root cause of many incorrect diagnoses is precisely that physicians do not take a good history and perform the necessary clinical examinations, have too little knowledge of the various diseases that require differential diagnosis, and rely excessively on ancillary tests (e.g., CT/MRI of the head or cervical spine, TCD, etc.) without understanding their limitations. For example, benign paroxysmal positional vertigo (BPPV) is misdiagnosed as multiple lacunar infarcts seen on CT/MRI of the head or degenerative lesions of the cervical spine seen on cervical spine examination without Dix-Hallpike examination. The main causes of dizziness: Understanding the common causes of dizziness will allow us to understand the main clinical features of these disorders, to maintain a correct diagnostic approach in our daily medical practice, and to avoid delays in diagnosis or excessive diagnostic testing due to inability to distinguish between common and rare diseases. Vertigo accounts for about half of all dizziness, and there are significantly more vestibular peripheral than vestibular central cases, 4 to 5 times more than the latter. Among the causes of periventricular vertigo, BPPV (about 1/2), vestibular neuronitis (about 1/4), and Meniere’s disease are the predominant causes and probably account for the vast majority of periventricular vertigo. Central vestibular vertigo has diverse but rare etiologies, including vascular, traumatic, tumor, demyelinating, and neurodegenerative diseases. It is important to note that vestibulocentric vertigo is almost always accompanied by other neurological signs and symptoms, except for migraine, and rarely is vertigo or dizziness the only manifestation. The etiology of non-vertigo dizziness is numerous and is by no means limited to neurological or otologic disorders. Numerous epidemiological studies suggest that the majority of chronic, persistent dizziness is mainly related to psychiatric disorders while transient or episodic dizziness is mostly associated with systemic diseases (e.g., anemia, infection, fever, hypovolemia, postural hypotension, diabetes mellitus, medication side effects, etc.). Evolution of dizziness etiology and diagnosis With the increased awareness of BPPV, its diagnosis has significantly increased and it has become the first cause of vertigo, which was rarely diagnosed by many physicians 10 years ago. Recent studies have found that many episodes of vertigo are associated with migraine, making migraine an important cause of episodic vertigo. What used to be called benign episodic vertigo (not accompanied by hearing or neurological symptoms) is thought to be a possible allelopathy of migraine. Vague and even erroneous clinical diagnosis of dizziness A large number of middle-aged and elderly people in China have long diagnosed chronic dizziness as vertebrobasilar insufficiency of blood supply (VBI) and considered it as a state that is not normal but does not meet the criteria for ischemia. Numerous prospective and retrospective clinical studies have demonstrated that simple dizziness or vertigo without other neurological manifestations is rarely caused by VBI. The International Classification of Ischemic Cerebrovascular Diseases and the International Classification of Diseases do not include VBI and consider it to be a TIA of the posterior circulation rather than a separate and specific disease. The promotion of the concept and diagnosis of “posterior circulation ischemia” replaced the diagnosis of VBI in China. The term “cervical vertigo” is also used by many physicians, but there is a lack of serious clinical studies on the accuracy of the definition and the reliability of the diagnostic criteria, and many of them use hypotheses instead of clinical evidence or even against the evidence. The studies to date have had weaknesses such as unverifiable diagnosis, lack of specific diagnostic methods, and inability to explain the large number of clinical inconsistencies, so the use of this vague definition and diagnosis is not recommended internationally. Many patients with vertigo have a combination of cervical spondylosis, but the vast majority of vertigo is not due to cervical spondylosis Simple dizziness, vertigo or imbalance strongly suggests a non-cerebrovascular cause. Of the 1666 patients with dizziness, 1297 had simple dizziness, vertigo, or imbalance, with no other symptoms, and only 9 of the 1297 patients with simple dizziness (0.7%) had stroke or TIA.