Hereditary Ataxias And Friedreich\'s Ataxia
Ataxia is a disorder of balance and coordination due to a neurological disorder. It is a state of balance, stopping or not falling. Coordination is to achieve harmony between different body parts in the targeted movement.
Hereditary ataxias may be due to autosomal dominant (OD), autosomal recessive (OR) and X. The definitive diagnosis of the disease is based on molecular studies.
TYPES OF ATAXIAS
Ataxies are divided into two according to the place of involvement in the body:
- Body ataxia: Only the body is involved. There is coordination disorder related to balance.
- Extremity ataxia: Only arms and legs are involved. Other than equilibrium coordination disorders in cerebellum lesions are also accompanied (such as tremors, difficulty in determining the distance).
The child with an ataxia walks irregularly, spreading his legs and leaning forward, like a sailor or drunk man walking on a ship in the wavy sea to maintain his balance.
According to the neurological involvement, ataxias are divided into three:
- Sensory Ataxia: It is seen in proprioceptive sensory tract lesions (spinal posterior cord tumors, spinocerebellar ataxias and MS). Ataxia of the trunk or only the lower extremities is present. Patients follow their legs with their eyes while standing and walking. They extend the support surface. They perform exaggerated hip and knee flexion. Loss of balance is unilateral.
- Vestibular Ataxia: It occurs in diseases like central and peripheral vestibular diseases such as stroke, MS, which involve the vestibular nuclei and their connection with the cerebellum and other regions. The ataxia is accompanied by vertigo, nausea and nystagmus.
- Cerebellar Ataxia: It occurs when the cerebellum or its connections are affected. Ataxia of the trunk and extremities, and dysarthria and nystagmus are present.
After a detailed evaluation of the patient, balance, control and coordination exercises, gait training, occupational therapy, and robotic rehabilitation are performed according to the patient's condition and the goals which have been set.
Aims and Goals
- To improve balance and postural reaction.
- To improve and increase joint and postural stabilization
- To ensure proper arm and leg movements
- To increase functionality in all environmental conditions
- Movements should be advanced from simple to complex: From static to dynamic, and from open eye to closed eye.
- Distal segments should be stabilized after proximal tonus and stabilization is gained.
- Treatment should be supported by appropriate home programs and sports activities.
Improvement of Balance
- The balance work must be started from the previous stage.
- Balance exercises are started from static position and followed by the development pattern of movement. For example, it is moved from lying face down to kneeling, turning, sitting and standing positions. At each stage, it is attempted to have the patient perceive the correct position and to try to deteriorate patient’s balance and her/his return to the correct position.
Balance in sitting
- Keep your eyes closed
- Weight transfer to the left and right
- Balance exercises with balance ball
- First eyes are open, then closed. Semiautomatic, automatic, static balance exercises.
- Making the exercise more challenging by changing arm positions and using balance ball
Standing Balance Exercises
- Balance training on normal support surface
- Balance training on narrow support surface
- Dynamic balance training
- Plyometric Exercises. Improves balance
If there is a problem in the support surface and stabilization;
- Walking on the wide support surface
- Walking by narrowing the surface
- Walking sideways
- Crossside walking
2- Frenkel Coordination Exercises. It is used in coordination disorder caused by neurological disease. Frenkel exercises consist of well planned, successive (lying, sitting and standing), slow series of movements.
Rather, it is used in vertigo and balance disorders related to unilateral vestibular disorder. Patients with sitting balance disorder also benefit from Catwthorne-Coooksey exercises.
Friedreich's ataxia (FA) is the most common form of autosomal recessive ataxia. It occurs by mutation of a gene locus on chromosome 9. It constitutes at least half of the hereditary ataxias, and 75% of ataxia that starts before the age of 25.
The main symptoms are progressive gait ataxia, speech impairment, loss of joint position and sense of vibration and absence of reflex in the legs.
Frataxin protein synthesis is reduced by altering gene expression on chromosome 9. Frataxin is essential for normal mitochondrial function. In the absence of frataxin, iron accumulates in the mitochondria of the cells. On the one hand, more free radicals are produced, while on the other hand the capacity to mobilize antioxidants is reduced. Excessively increased intracellular iron increases free radical formation and mitochondrial destruction. Thus, cell death occurs in neurons in the spinal cord and peripheral nervous system.
Prevalence: The prevalence of Friedreich's ataxia is 1 in 30.000-50.000. The disease usually begins at the age of 8-15 before the age of 20 years. Walking is lost 15 years after the onset of the disease. After the age of 45, more than 95% of patients become wheelchair dependent. After the onset of the disease, patients live an average of 35 years. Friedreich's ataxia is mostly found in whites. There is no frataxin gene expansion in Black Africans and Asians.
Clinical Features: At the beginning of the disease, the patient complains of frequent falls, imbalance and difficulty in walking. Cerebellar findings such as extremity and trunk ataxia are present in all patients. Nystagmus in the eye is seen in 20% of the cases.
Complaints are accompanied by dysarthria after a few years. Dysphagia occurs in the late stages of the disease, especially when receiving liquid food. Cognitive functions are usually maintained.
Vibration and sense of position is one of the findings detected in approximately 80% of cases. Reflexes decrease or cannot be taken in 75% of the cases. 67-88% of patients suffer from muscle loss in their small muscles of the hands and feet, especially apparent in the lower extremities. Muscle tone may be normal or decreased.
Optical atrophy is detected in 30% of the patients but vision loss may not be present. Hearing loss develops in 20% and diabetes develops in 10%.
In the late stage of the disease legs and feet can be cold and cyanotic.
Skeletal deformities such as dome palate, scoliosis, pes cavus and hypertrophic cardiomyopathy can be seen.
Electrophysiological examinations: Decreased sensory conduction velocity is found by means of EMG. The motor transmission speed is normal or slightly reduced.
Imaging: MRI and brainstem are normal and cerebellar atrophy is detected. Atrophy may be present in the spinal cord, especially in the cervix.
Treatment: There is no medication to change the natural course of Fredreich's ataxia. Standard treatment is regulated for heart failure, arrhythmia and diabetes.
Coenzyme Q is an antioxidant that eliminates the free radicals produced by excess mitochondrial iron. The combination of coenzyme Q (400mg / day) and vitamin E (2100 IU / day) slowed progression in some clinical features and led to a significant improvement in cardiac function.
Drug studies aimed at increasing the level of frataxin can be promising. These are idebenone, which improves mitochondrial function and reduces free radical production, and deferiprone, which reduces Fe accumulation in mitochondria. There was a decrease in FFA with idebenone 20mg / kg / day given to FA patients for 1 year, but there was a tendency to improve emotional, social and school quality of life. It has been suggested that daily combination of 20 mg / kg deferiprone and idebenone may be effective on neurological function and cardiac hypertrophy.
Rehabilitation: These patients should receive regular physical therapy and rehabilitation. As described above, balance, coordination, gait, strengthening, speech and swallowing therapy, occupational therapy and robotic rehabilitation applications can be conducted during the rehabilitation. Orthopedic shoes can improve gait.
Surgical Treatment: Scoliosis and foot deformities corrective surgery can be done.