The term chronic subjective dizziness (CSD) is used to describe a commonly encountered type of

dizziness Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness. Dizziness is a common medical c ...

that is not easily categorized into one of several other types, and for which the physical examination is typically normal. Patients with CSD frequently initially suffer a sudden injury of some sort to their vestibular system, the neurologic network that preserves sense of balance. Even after this initial injury has healed, people with CSD usually describe a vague sense of unsteadiness worsened by triggers in their environment such as high places, standing on moving objects, or standing in motion-rich environments like busy streets or crowds. There is a clear indication that anxiety and other mental illnesses play a role in the dizziness symptoms that occur with CSD. However, the condition is categorized as chronic functional vestibular disorder, not as a structural or psychiatric condition. Proposals include renaming it persistent postural-perceptual dizziness (PPPD) which better captures the multiple aspects of the condition under its title. It is under that title the World Health Organization has included PPPD in its draft list of diagnoses to be included to the next edition of the International Classification of Diseases (ICD-11) in 2017.

Signs and symptoms

Symptoms can include: * A constant sense of unsteadiness, rocking or swaying, dizziness or lightheadedness * Disequilibrium on most days for at least 3 months * Spatial orientation problems * Off-kilter sensation * Extreme sensitivity to movement and/or complex visual stimuli such as grocery stores or driving in certain weather conditions * Worsening dizziness with experience of complex visual environments such as walking through a grocery store * Heavy-headedness; a feeling of floating, wooziness Symptoms of CSD can be worsened by any self-precipitated motion, usually from the head, or the witnessing of motion from another subject. These are usually less noticeable when the person is lying still.

Diagnosis

Diagnosis can be difficult as there is not a specific test for PPPD but rather a series of elimination tests for other vestibular causes. If elimination test are all normal and the symptoms match a PPPD diagnosis is possible.

Treatment

Effective treatments include vestibular rehabilitation therapy, medications such as

SSRI Selective serotonin reuptake inhibitors (SSRIs) are a class of drugs that are typically used as antidepressants in the treatment of major depressive disorder, anxiety disorders, and other psychological conditions. SSRIs increase the extracellul ...

s and psychotherapy, including the most effectively represented cognitive behavioral therapy. Promising results were also found with

transcranial direct-current stimulation Transcranial direct current stimulation (tDCS) is a form of neuromodulation that uses constant, low direct current delivered via electrodes on the head. It was originally developed to help patients with brain injuries or neuropsychiatric conditio ...

combined with vestibular rehabilitation with significant improvement in symptoms of patients over a sham group in an exploratory study. More recently, a study showed non-invasive

vagus nerve stimulation Vagus nerve stimulation (VNS) is a medical treatment that involves delivering electrical impulses to the vagus nerve. It is used as an add-on treatment for certain types of intractable epilepsy and treatment-resistant depression. Medical use VNS ...

to offer significant effect in PPPD patients regarding the quality of life, postural balance control, attack severity and depression level, with no reported serious side effects. The findings are argued to imply nVNS to be a safe and promising treatment option in patients with treatment-refractory PPPD and suggesting the need for further research.{{cite journal, title=Non-invasive vagus nerve stimulation significantly improves quality of life in patients with persistent postural-perceptual dizziness, journal=Journal of Neurology, pmid=29785522 , doi=10.1007/s00415-018-8894-8, volume=265, issue=Suppl 1, pages=63–69 , last1 = Eren , first1 = O , last2 = Filippopulos, first2 = F , last3 = Sönmez , first3 = K , last4 = Möhwald, first4 = K , last5 = Straube, first5 = A , last6 = Schöberl , first6 = F, year=2018, s2cid=29167439

History

Perhaps the first account of CSD was the German neurologist Karl Westphal's portrayal in the late 1800s of people who suffered

anxiety Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...

and spatial disorientation when shopping in town squares. This phenomenon was called " agoraphobia", meaning a fear of the marketplace. The term is now used to describe a psychological fear, but Westphal's original description included many symptoms of dizziness and imbalance not included in the modern psychiatric definition. Unlike people who feel anxious in crowds because they feel something bad will happen, people with CSD may dislike crowds because all the movement leads to a sensation of dizziness.

References

Symptoms Neurological disorders