Balance Disorders: Dizziness and Vertigo

Jed A. Kwartler MD, MBA

Dina Leyden PT

Gina Byrnes MSW, LCSW

What we will talk about

• How does the balance system work• What can go wrong in the system• How do we figure things out• What can we do to fix things

Why do we need a balance system?

• Balance, posture• Vestibular• Vision• Proprioception (ankle, etc)

• Stable sensory platform• Especially for vision

• Spatial orientation• Which way is up• Important in space, underwater,

in the air, and in underground tunnels

Organization of Balance System

Anatomy

Canal anatomy• Each canal has a swelling at

its base, called the ampulla

• The crista is a saddle--shaped receptor epithelium covered with hair cells

• The stereocillia of the cells are embedded in a gelatinous membrane (the cupula) that spans the ampulla and forms a barrier across it

The three semicircular canals lie in 3 orthogonal planes

Cochlear N

Vestibular N

HorizontalCanal

Vestibulo-Cochlear N

(Nerve VIII)

Cochlea

PosteriorVerticalCanal

AnteriorVerticalCanal

Canal orientation

The three semicircular canals are approximately orthogonal to each other. One is 30 deg above horizontal, while the anterior and posterior are vertical (approximately 45° from the sagittal plane)

Notice that they are arranged in pairs:

R Horizontal -- L Horizontal

R Anterior -- L Posterior

R Posterior -- L Anterior

The semicircular canals are functionally paired to eye muscles

• The canals lie in roughly the same planes as the extraocular muscles:

Horizontal canals: lateral and medial recti.LARP: left vertical recti, right obliques.RALP: right vertical recti, left obliques.

• Each canal excites a pair of muscles and inhibits a pair of muscles in its plane. Its partner excites the muscles it inhibits, and vice-versa.

Canal function

• When the head rotates, inertia causes the fluid in the canals to lag behind, exerting force on the cupula, which in turn bends the stereocillia

• Ipsilateral rotation is excitatory, contralateral is inhibitory; each canal pair works as a push-pull system

There are 3 major vestibular reflexes

• Vestibulo-ocular reflex – keep the eyes still in space when the head moves.

• Vestibulo-colic reflex – keeps the head still in space – or on a level plane when you walk.

• Vestibular-spinal reflex – adjusts posture for rapid changes in position.

First step – Take a history

What are we looking for in the history

• Describing what the sensation feels like• When and how did it start• Pattern

Constant, episodic, getting worse or better• What makes it worse, makes it better

Foods, activities, movements, time• Associated symptoms

Headache, sensorimotor changes, metabolic • Other factors

Sleep, stress, medications, mobility, general condition

Physical Examination

• Orthostatic blood pressure• General head and neck exam• Otoneurologic exam

Eye movements Postural control and coordination Provocative movements

• “testing for crystals”• Visual fixation/suppression of nystagmus• Dynamic visual acuity with head movement• Dizziness/nystagmus with air pressure or loud sound

Testing

• Hearing test• Tests of balance function

VNG Rotary Chair Posturography Head thrust VEMP (cervical or ocular)

• Functional balance assessment by PT

Vestibular• Menieres• Vestibular Neuritis• Benign position vertigo• Idiopathic recurrent vestibulopathy

Neurologic• Migraine• Concussion• Stroke/Ischemia• Neuropathy• Visual disturbance

Other• Cardiac – pressure, output, arrythmia, postural• Medications• Metabolic – endocrine• Sleep apnea• Stress/anxiety• Mobility and general conditioning