Ataxia - Dysfunction of Part of the Nervous System That Control Coordination

Reanna Conway

Burrell        

 Honors Anatomy Physiology

Fall Semester

        Ataxia

   Ataxia is the clinical term implying dysfunction of part of the nervous system that control coordination.   Ataxia on only one side of the body is referred to as hemiataxia.  The three types of ataxia are cerebellar, sensory, and vestibular.

   Cerebellar ataxia is due to a dysfunction in the cerebellum of the brain.  The cerebellum processes neural information used in ongoing movements and motor planning.  People with cerebellar ataxia have trouble regulating the rhythm, direction, velocity, force, and range of muscle contractions. This results in irregular and uncoordinated movements such as dysarthria, dysphagia and difficulty with eye movements.  Cerebellar ataxia patients also have poor coordination and the inability to perform tandem gait.  Tandem gait is when the toes of the back foot touch the heel of the front foot after each step.  As the condition progresses walking is characterized by high stepping, lurching from side to side, and staggering. An impairment in speech articulation is also present.  It is characterized by speech with a slower rate, irregular rhythm, slurred words, and a tremor of the voice.    

   Sensory ataxia refers to the loss of sensitivity to the positions of body parts and joints.  Sensory ataxia has a gait with heavy heel strikes and postural instability. When patients stand with their feet together and close their eyes instability worsens and ends in a possible fall.  Vestibular ataxia is characterized by vertigo, nausea, and vomiting.  It is due to a dysfunction in the vestibular system.

   All types of ataxia have overlapping causes.  A focal lesion to the central nervous system, such as a stroke or brain tumor, will cause the type of ataxia corresponding to the area of the lesion.  Substances such as ethanol can cause ataxia because it has a depressant effect on the central nervous system.  Ataxia can also be caused by radiation poisoning of more than 30 Grays or a vitamin B12 deficiency.  Ataxia may depend on degenerative hereditary effects on the spine/cerebellum.

   The effectiveness of ataxia treatments depends on the underlying cause.  Treatments can reduce the effects of ataxia, but is unlikely to completely eliminate them.   Recovery is usually better in individuals with injuries such as a stroke or benign tumor than those with a neurological degenerative disease.  The disorder can be managed with drug treatments, physical therapy, and occupational therapy.  

   Physical therapy focuses on adapting activities and motor learning to retrain specific functional motor patterns.  The most common physical therapy treatments are Frenkel exercises and proprioceptive neuromuscular facilitation (PNF).  Frenkel exercises are a set of exercises developed by Professor Heinrich Sebastian Frenkel to treat ataxia, especially cerebellar ataxia.  They are a series of slow repetitious exercises that increase in difficulty over time. The patient carefully watches his or her movements and corrects them as needed.  Research has shown that 20,000 to 30,000 repetitions are needed in order to produce results.  Frenkel’s book on ataxia states that the best way is to perform the exercises for 3 minutes with a timer.  After 3 minutes a 15-30 minute break should be taken.  These sessions should then be continued every day for six weeks about six times a day.   PNF stretching is a set of stretching techniques used to improve range of motion in order to help rehabilitation and motor performance.  A PNF stretch involves a shortening contraction of the opposing muscle to place the target muscle on stretch.  This is followed by an isometric contraction of the target muscle.