Ataxia

Clinic

• Ataxia is a COD, since it has a variety of Sigh / Symptoms which have a common axis, which is named cerebellum. These Sign / Symptoms arise from different pars of cerebellum and their extra cerebellar centers. As I explained it in more details in Nerocognitive considerations, Ultra complexity of our nervous system does not let neuroscientists to localized Functional units Anatomically / Physiologically. Although it is very Tempting to isolate the functional units of nervous system, But we are not allowed to delay the treatment of patients until these physiological units are isolated. So TLT tries to make a model by use these functional units only by their function and dysfunction. Here is the list of Ataxia entities:
  • Dysarthria
  • Gait abnormality: Balance disturbances
  • Vertigo: Postural instability
  • Unsteadiness
  • Ext, Incoordination: Dysdiadochokinesia, Dysmetria, Peculiar writing abnormalities
  • Ext, Awkwardness
  • Nystagmus
  • Tremor
• Lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements.
• Ataxia can be limited to one side of the body, which is referred to as hemiataxia.
• Dystaxia is a mild degree of ataxia.

Here we have a confusing rubric, named Ataxia. Since it is used in its general them, means unbalance movements. I prefer using this rubric as a general guiding in all problems of Balance system, But for finding one or two miasm, you should add an entity to it.

Cerebellar ataxia

Dysfunction of the cerebrocerebellum (Lateral hemispheres) Appendicular ataxia	Intention tremor Coarse trembling Accentuated over the execution of voluntary movements Possibly involving head, eyes, limbs and torso	Peculiar writing abnormalities Large, unequal letters Irregular underlining	Peculiar Dysarthria Slurred speech characterized by explosive variations in voice intensity despite a regular rhythm	Dysdiadochokinesia Inability to perform rapidly alternating movements which could involve rapidly switching from pronation to supination of the forearm. Movements become more irregular with increases of speed.	Dysmetria Hypometria or overshooting Hypermetria Inability to judge distances or ranges of movement happens.	Rebound phenomenon Loss of the check reflex	Schmahmann's syndrome Patients may exhibit a constellation of subtle to overt cognitive symptoms
Dysfunction of the spinocerebellum (Vermis and areas near the midline)	Truncal ataxia: Uncertain starts and stops Lateral deviations Unequal steps
Vestibulocerebellum dysfunction Flocculonodular lobe	Balance disturbances Control of eye movements Postural instability Negative Romberg's test

Sensory Ataxia

Clinic

• Sensory Ataxia is a form of ataxia caused not by cerebellar dysfunction
• It is due to
  • Loss of Sensory input / Proprioception (Positions of joint and body parts)
  • Dysfunction of dorsal columns of spinal cord (Because they carry proprioceptive information up to brain)
  • Dysfunction of the various parts of the brain that receive positional information, including the cerebellum, thalamus, and parietal lobes.

Vestibular Ataxia

• Ataxia due to dysfunction of the vestibular system
• Acute and unilateral cases is associated with prominent vertigo, nausea, and vomiting.
• In chronic bilateral cases, dysequilibrium may be the only presentation.

Truncal ataxia

Truncal ataxia is caused by midline damage to the cerebellar vermis.