Ataxia is characterized by a lack of muscle coordination and can result in symptoms such as unsteady movements, dizziness, and balance disorders. The cerebellum, divided into the archicerebellum, paleocerebellum, and neocerebellum, plays a crucial role in coordinating movement and posture. Various factors such as lesions in the sensory systems, neurological disorders, and external stimuli can contribute to vertigo and balance impairments.

1. Julius King Kwedhi

2.  The word "ataxia", comes from the Greek
word, "a taxis" meaning "without order or
incoordination". The word ataxia means
without coordination.
(http://www.ataxia.org/learn/ataxia-diagnosis.aspx)
 Inability to coordinate voluntary muscle
movements; unsteady movements and
staggering gait. (WordWeb Dictionary)

7. Involved in movement
coordination.
Receives sensory information
and then influences descending
motor pathways to produce fine,
smooth, and coordinated
motion.

8.  THE ARCHICEREBELLUM (vestibulocerebellum)
Primarily controls posture and balance, also
movement of the head and eyes.
It receives afferent signals from the vestibular
apparatus and then sends efferent fibers to the
appropriate descending motor pathways.
 THE PALEOCEREBELLUM (spinocerebellum)
Primarily controls movement of the proximal
portions of the limbs.
It receives sensory information on limb position and
muscle tone and then modifies and coordinates
these movements through efferent pathways to
the appropriate descending motor pathways.
 THE NEOCEREBELLUM (cerebrocerebellum).
The largest part. Coordinates movement of distal
portions of the limbs.
It receives input from the cerebral cortex and thus
helps in the planning of motor activity (e.g.,
seeing an object and then planning and
executing the movement of the arm and hand to
pick it up).

10. Vibrations of the
tympanic membrane
 Pressure changes
imparted on oval
window of cochlea 
Basilar membrane
vibration 
depolarization of hair
cells  creation of an
electrical signal which
is transduced through
the afferent nerve
fibers to cochlea
nerve

11. The cochlea transduces sound into electrical
signals.
Axons convey these signals to the dorsal and
ventral cochlear nuclei, where it is
tonotopically organized.
Following a series of integrated relay
pathways, the ascending pathway projects to
the thalamus (medial geniculate bodies) and
then the acoustic cortex in the transverse
gyrus of the temporal lobe, where
information is tonotopically represented
(low, middle, and high tones).

14.  Three sensory systems serving spatial
orientation and posture:
1. The vestibular system
2. The visual system (retina to occipital
cortex) and the
3. Somatosensory system that conveys
peripheral information from skin, joint, and
muscle receptors.
 These 3 stabilizing systems overlap enough to
compensate (partially or completely) for
each other’s deficiencies

15.  Dizziness
 Vertigo
 Faintness
 Disorder of gait (Ataxia, Disorders of
balance)
 Falls
 Nausea
 Vomitting

16.  Physiologic Vertigo
a) When brain is confronted with an intersensory mismatch between the 3
stabilizing sensory systems (e.g. car sickness, height vertigo)
b) Vestibular system is in unusual head movements it’s not adapted to (e.g.
seasickness)
c) Unusual head/neck position (e.g. extreme extension when painting
ceiling)
d) Following a spin (Physiologic postrotational vertigo)
 Pathologic Vertigo:
Due to lesions of visual, somatosensory or vestibular
systems
1) Peripheral vertigo
2) Central vertigo
3) Psychogenic vertigo

17.  Localization of lesions & Common causes:
 Labyrinthine,
• Acute unilateral dysfunction:
• Infection, Trauma, Ischemia
• E.g.Occluded labyrinthine branch of auditory artery 
Labyrinthine Ischemia  abrupt onset of severe vertigo,
nausea, vomiting
• Acute bilateral dysfunction: toxins, drugs & alcohol
• Recurrent unilateral dysfunction: Meniere’s disease
• Positional vertigo: Trauma. Aggravated by head
position. Nystagmus – tortional & upbeating. Benign
Paroxysmal Position Position(ing) Vertigo BPPV
 Vestibular nerve
• Diseases affecting the cochlear nerve in petrous bone,
e.g. Tumour (schwanoma). Tinnismus, hearing loss

18.  Localization:
• Brain stem & cerebellum (vestibulocerebellum)
 Common causes:
 Stroke
 Brain tumor
 Mltiple Sclerosis
 Infection
 Basilar migraine

20.  Antimigranous treatment
 Antihistamines (Meclizine, Promethazine)
 Benzodiazepines (Diazepam, Clonazepam)
 Phenothiazepines (Prochlorperazine)
 Anticholinergic (Scopolamine transdermal)
 Sympathomimetics (Ephedrine)

21.  Mechanism:
 Pathology of one or more of the 3 sensory
systems serving spatial orientation and
posture:
1. The vestibular system
2. The visual system (retina to occipital
cortex) and the
3. Somatosensory system that conveys
peripheral information from skin, joint, and
muscle receptors.

22.  Cerebellar Gait Ataxia
 A wide base of support,
 Lateral instability of the trunk,
 Erratic foot placement, and
 Decompensation of balance when attempting to
walk tandem.
 Early feature: Difficulty maintaining balance
when turning.
 Patient unable to walk tandem heel to toe, and
display truncal sway in narrow-based or tandem
stance.
 Patient show considerable change in their
tendency to fall in daily life.

23.  Alcohol
 Hereditary cerebellar degeneration (e.g.
multiple system atrophy)
 Stroke (in elderly)
 Trauma
 Tumour
 Neurodegenerative disease (e.g. multiple
system atrophy)

24.  Balance depends on:
 high-quality sensory information from
 the visual system
 the vestibular systems and
 proprioception.
 Balance impairment and instability due to loss
or degradation of sensory information, leading
to:
 Sensory ataxia of tabetic neurosyphilis,

25.  Neuropathy affecting large fibers.
 Vitamin B12 deficiency (demyelination 
large-fiber sensory loss in the spinal cord
and peripheral nervous system)

26.  Diminished joint position and vibration sense in
the lower limbs.
 Destabilized standing posture with eyes closed
 Patients often look down at their feet when
walking and do poorly in the dark.
 Imbalance due to bilateral vestibular loss,
caused by disease or by exposure to ototoxic
drugs.

27.  Rohkamm R,. (2004). Colour Atlas of
Neurology, Thieme, Stuttgart, Germany
 Netter F. H., et al (2004). Atlas of
Neuroanatomy And Neurophysiology, Stalevo,
USA
 Hauser S. L.,& Josephson S. A., (2010).
Harrison’s Neurology In Clinical Medicine,
McGraw Hill Medical, New York, USA