Nystagmus
Balance Disorders Symptoms
Dizziness and imbalance is the second most common medical complaint people report to their doctors. It is estimated that as many as 40% of adults are affected at some time in their life. There are a very wide range of possible causes and optimum management may involve Neurologists, Cardiologists and General Physicians as well ENT Surgeons and Neuro-Otologists so accurate diagnosis is therefore essential. Fortunately most causes of dizziness and imbalance are detectable with today’s sophisticated computerised diagnostics, whilst appropriate medical or surgical treatment is also usually very effective.
Because the symptoms are subjective, patients may use various terms to try to describe the unpleasant sensations they feel to their doctor. This section therefore lists and explains many of these common terms.
Dizziness
Dizziness is a term which encompasses a broad range of sensations from severe rotational vertigo to lightheadedness, dysequilibrium or imbalance. Clinically it is commonly used to describe the type of medical condition in a non-specific way before comprehensive specialist evaluation has established a precise diagnosis.
Nausea
Nausea is a sensation of unease in the stomach associated with an involuntary urge to vomit. There are many nerve connections between the vestibular system and the vomiting centre and trigger zone in the medulla, so that nausea is a very common associated feature with any type of dizziness or imbalance.
Motion Sickness
Motion sickness or travel sickness is characterised by nausea, vomiting, pallor and sweating when travelling in a moving vehicle, typically a car. It is a physiological response to a mismatch between vestibular and visual information about the moving environment. Clinically it appears that the vestibular system in these individuals is programmed in a way that makes them very sensitive to movement. People with a background history of motion sickness are more likely to suffer vestibular compensation problems with any type of dizziness or balance disorder.
Positional Dizziness
This term refers to conditions in which sudden changes of head position, such as lying down or looking upwards at a high shelf, induce dizziness. Benign paroxysmal positional vertigo (BPPV) is a disorder where degenerative dust particles build up in the fluid inside the labyrinth. Sudden movements of the head shake up and disturb the debris., which subsequently settle under the force of gravity stimulating sensitive balance cells in the ampulla leading to delayed transient vertigo. Patients with an uncompensated vestibular disorder may often report induced dizziness during the movement due to a “sensitive” labyrinth. Persistent positional vertigo which does not fade away may be due to a central (brain) problem.
Vertigo
Vertigo is the illusion that one’s body or the environment is spinning or tumbling and usually indicates a vestibular problem. Any sensation of motion, such as tilting or falling can also be caused by vestibular disease.
Lightheadedness
Lightheadedness or faintness, also termed pre-syncopal dizziness, is a non-vestibular type of dizziness due to a temporary impairment of oxygenated blood to the balance part of the brain. The patient may also describe a feeling of detachment from their surroundings. The symptom may be due to a transient ischaemic attack (TIA), which is a feature of arteriosclerotic vascular disease when a small blood clot may become detached from an arterial wall plaque and temporarily block part of the vertebro-basilar blood vessel network. It may be a symptom of basilar migraine when there is temporary blood vessel spasm, or may be associated with acute anxiety or panic attacks when palpitations and a heavy feeling in the chest are common additional complaints.
Muzziness
Patients with vestibular problems frequently use this term to describe the sensation of an “unclear” head, as if it is “filled with cotton wool”. It represents the mildest form of mismatch between the incorrect information generated by a damaged labyrinth and the information expected by the central “balance computer” in the brain. It is commonly reported by patients with an uncompensated peripheral vestibular disorder and usually affects one’s ability to concentrate on mental tasks. The extra effort required to complete everyday tasks often results in excessive tiredness.
Visual Vertigo
Horizontal and vertical visual cues provide important sensory information to enable orientation in our surroundings. Patients with an uncompensated vestibular disorder frequently have a “sensitive” balance system which can literally become overwhelmed by rapidly changing visual stimuli. Patients may report a wide range of complaints such as difficulty riding an escalator in a department store, driving a car on a motorway, working at a computer screen or watching TV, or even maintaining satisfactory balance whilst walking outside in sunlight which can cause variable reflections from smooth irregular surfaces, such as water, or when shining through the swaying foliage of trees or plants. There is a wide variation in the way different people’s balance system is programmed, and some individuals are much more reliant on visual cues than others, probably rendering them more like to suffer Visual Vertigo with a vestibular disorder.
Imbalance
Imbalance or dysequilibrium is a term used to denote difficulty maintaining one’s centre of gravity in a set position. Rather like dizziness it is a non-specific term which may be due to a wide spectrum of disorders. Imbalance is not a specific diagnosis but generally refers to a type of medical problem.
Movement Dysequilibrium
Transient imbalance on sudden movement is a common feature of an uncompensated vestibular disorder. Such patients frequently have an abnormality of their vestibular-ocular reflexes and sudden movements give rise to an “inertia” effect, when the head and the body do not seem to move synchronously in a quick, seamless co-ordinated manner. It is frequently helped by a customised course of vestibular rehabilitation exercises.
Mal De Debarquement Syndrome
After a boat trip, healthy people will often feel a slight rocking sensation for several hours after disembarkation, a phenomenon called mal de debarquement. When this symptom continues for more than a few weeks it is called the mal de debarquement syndrome.
Drop Attacks
These abrupt episodes can occur without any warning in various end stage peripheral vestibular disorders, so called Tumarkin otolithic crises. They represent a serious problem as the lack of any warning means that patients are potentially at real risk of serious accidental injury and should avoid potentially dangerous activities including driving. Destructive surgical procedures are often warranted to guarantee abolishing the episodes. Drop attacks may also occur with acute central (brain) ischaemic episodes or other neurological disorders such as epilepsy.
Oscillopsia
Oscillopsia is the illusion that the environment is moving. The abnormal eye movements in nystagmus often cause blurring of vision and horizontal oscillopsia. Vestibular damage may cause impairment of the vestibular-ocular reflex, which results in an inability to stablise an image on the retina during head movements. Bobbing oscillopsia is a condition when objects or the horizon appear to jump or bob up and down spontaneously when the subject is walking or running. Bobbing oscillopsia is typically seen in bilateral peripheral vestibular failure and is a classic symptom of aminoglycoside ototoxicity.
Trauma
Dizzinesss and balance problems after a head injury is common. A skull fracture passing through the inner ear results in a fistula with sudden loss of perilymph causing acute vertigo and a total sensorineural hearing loss. A closed head injury can also cause vestibular symptoms by inner ear concussion, or torsion of the delicate nerve and blood supply to the inner ear as the brain is shaken violently on impact (contre coup injury). Trauma is a recognised causative factor in some cases of BPPV and in about 1 in 15 cases of Meniere’s syndrome.
Whiplash Injury
Whiplash is the term given to a sudden flexion-extension injury of the neck. It is very common after any type road traffic accident, when the occupant is thrown forwards on impact by their momentum only to be stopped suddenly by their seat-belt causing a jolting injury to the neck. Dizziness is a very common early symptom in addition to local pain and muscle tension in the neck and shoulders. Whiplash injuries commonly lead to medico-legal claims for compensation.
Nystagmus
The control of eye movements is very closely linked to the balance system. The vestibular-ocular reflex (VOR) is an essential function which ensures that when we turn our head quickly in any direction the axis of the eyes automatically move synchronously and almost immediately so that we can still see where we are and rapidly re-orientate ourself. This vestibular-ocular reflex (VOR) is programmed very early in life with the rest of the vestibular system. It is a completely separate function to visual acuity, which is the ability of the eyes to focus clearly in any fixed position.
Balance disorders often cause wrong information to be sent to the eyes. Abnormal electrical activity in the balance organ (labyrinth) or balance connections causes system confusion. The eye reflex (VOR) is stimulated as if the head has moved quickly to a certain position. The eyes mistakenly move to that position, but quickly register that they have been fooled and almost immediately move back to their correct position of alignment with the head. This eye movement anomaly is termed nystagmus and is commonly seen in many types of balance disorder. Unidirectional spontaneous horizontal nystagmus is typical of a peripheral labyrinthine disorder. Bilateral horizontal or vertical nystagmusis is typical of a central (brain) disorder. Torsional or rotatory nystagmus is typically seen in BPPV. Nystagmus is not a diagnosis, however, and may on occasions be present at birth due to a congenital fault in the VOR pathways or other visual impairments.
Diagnostics
Because of the wide spectrum of possible causes of dizziness and imbalance an extensive range of specialised audiological, vestibular, imaging and other investigations may be necessary to make an accurate diagnosis.
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