Medulloblastoma is a rapidly-growing tumor of the cerebellum, this area controls balance, posture and sophisticated motor functions like finer hand movements, speech, and swallowing. With the goal of, complete resection, major complications during tumor removal are usually caused by damage to the brain stem and injury to the lower cranial nerves.It has been reported that those children present Ataxia after resection. So the purpose of this study is to investigate the effectiveness of using a selected dual-task- training program to improve postural stability in those Children.

Most patients present with symptoms of hydrocephalus due to obstruction by tumor at the level of the fourth ventricle or cerebral aqueduct, and ataxia (Martin et al., 2014). If the tumor is large enough, the lesion itself can also cause mass effect and increased intracranial pressure. Furthermore, direct structural damage from the children can thus present with nausea, vomiting, ataxia,diplopia.

Ataxia in children is a common clinical sign of various origins consisting of impaired coordination of movement and balance with a lack of muscle control during voluntary activity. Ataxia is most frequently caused by dysfunction of the complex circuitry connecting the basal ganglia, cerebellum and cerebral cortex, and this type of involvement is recorded as "cerebellar ataxia.

Recently, the evidence for procedural memory training has advanced sophistication to suggest and ultimately prove that automaticity of a primary (motor task can be developed through exposure to massive repetitions practice) and the forced subconscious processing using dual task interference (Bermúdez, 2017).

The Objectives of the Study:

1- Aim of the Study: Determining the efficacy of "Dual Task Training in children with ataxia after Medulloblastoma Resection regarding "Static Balance" and "Dynamic Balance" as indicators of Postural Control

2-Specific Objectives:

1. Assess static balance by measuring center of pressure using force plate mode in the humac balance system.
2. Assess dynamic balance by using tilt mode in the humac balance system .
3. Evaluate the improvement on functional status and independence in ADL activities by functional independence measurement.
4. Determine the more effective program for rehabilitation of children with ataxia

3-Secondary Objectives:

1. Assess the degree of ataxia in children after medulloblastoma resection by SARA scale.
2. Detect the effect of cognitive interference on postural stability and balance.
3. Detect if there is improvement in cognitve function after dual task training.

Inclusion Criteria:

1. Age range from (5-10 years).
2. Severity of ataxia will be from 15-30 by SARA scale.
3. Children after 2 months of medulloblastoma resection.
4. They can stand and walk with minimal support.
5. They have good cognition, compliance, and ability to understand and execute test instructions.
6. Children receiving radiotherapy and chemotherapy sessions
7. They are medically stable

Exclusion Criteria:

Children will be excluded from the study if they have

1. Any neuromuscular disorder.
2. Visual impairment.
3. Cognitive problem
4. Convulsion.
5. Peripheral neuropathy due to chemotherapy.