Why am I dizzy?

A common symptom post concussion is dizziness and feeling off balance. We explored in the last section what this may mean if it is linked to exercise but what if the dizziness is at rest and less predictable?

This is where your physiotherapist will be able to assess where the source of the problem lies… and this is sometimes quite challenging as dizziness can be caused by many factors post concussion.

A thorough subjective history into aggravating factors, easing factors, duration of dizziness, frequency of dizziness and a description of the symptoms, will help guide our assessment.

Areas to check during an assessment for dizziness post concussion is the peripheral vestibular system, the central vestibular system and the upper cervical spine.

Let’s start with what we mean by the ‘vestibular system’?

The vestibular system is the sensory system that provides the leading contribution to the sense of balance and spatial orientation for the purpose of coordinating movement with balance. The vestibular organs located in the inner ear are in a state of symmetrically tonic activity, that when excited stimulate the central vestibular system. This information, along with proprioceptive and ocular input, is processed by the central vestibular pathways and maintains our sense of balance and position.

The vestibular system is broadly categorized into both peripheral and central components. The peripheral system is bilaterally composed of three semicircular canals (posterior, superior, lateral) and the otolithic organs (saccule and utricle). The semicircular canals detect rotational head movement while the utricle and saccule respond to linear acceleration and gravity, respectively. Peripheral Vestibular Disorders are limited to the vestibulocochlear nerve (CN VIII) and all distal structures.

The central vestibular pathways are those information highways otherwise known as neural tracts that relay this information from the vestibulocochlear nerve to other parts of our brain, about our position in space. This information is vital for maintaining our posture (so we don’t fall over when we move) and our gaze stability (so our vision does not blur when we move)

The information about where we are in space from the vestibular nerve helps our cerebellum coordinate the correct postural muscles to keep us upright via the vestibulospinal and reticulospinal tracts.

‘Gaze stability’ is achieved by the Vestibular Ocular Reflex (VOR) which uses information from the vestibular nerve about our head position, to stimulate the correct eye muscles to maintain your focus on a target- try focusing on an object and shaking your head- it doesn’t matter what speed or direction, your focus stays very true, all thanks to this reflex šŸ™‚

After a concussion, we may see trauma to the peripheral vestibular organs or a dysfunction to the central vestibular pathways. Due to the complexity of the system, even a mild dysfunction in the information processing may lead to feelings of instability, dizziness and/or visual disturbances. Our clever cerebellum tries to correct any inaccuracies but this can take time and so we teach you strategies and training exercises to help speed up the process.

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