Evidence of Cerebellar Dysfunction in Children with Myelomeningocele

Review Article

Phys Med Rehabil Int. 2017; 4(1): 1109.

Evidence of Cerebellar Dysfunction in Children with Myelomeningocele?

Martin S¹* and Kitzman P²

¹Department of Physical Therapy, College of Education and Health Sciences, University of Evansville, USA

²Department of Rehabilitation Sciences, University of Kentucky, USA

*Corresponding author: Suzanne Martin, Department of Physical Therapy, University of Evansville, 1800 Lincoln Avenue, Evansville, USA

Received: January 21, 2017; Accepted: February 13, 2017; Published: February 15, 2017


Structural differences in the development of the cerebellum in children with spina bifida myelomeningocele are associated with functional deficits in movement, timing, and attention. Furthermore, these structural and functional deficits contribute to uneven development of perception and cognition. Studies are reviewed that provide some understanding of the reason such a mixed pattern of assets and deficits within the same area is seen in these children. Motor learning and adaptation are relative strengths while predictive motor control is not. Upper limb function and visual perception are problematic as is timing and attention. In utero damage to the cerebellum may provide an explanation for this mixed pattern. Early damage can negatively impact the development of cerebellar circuits which could interfere with learning. Clinicians need to be aware of the relative strengths and weaknesses in children with spina bifida myelomeningocele in order to individualize early intervention treatment plans, optimize motor learning, and promote maximal participation in daily life.

Keywords: Cerebellar Dysfunction; Spina Bifida; Myelomeningocele; Perception; Motor Learning


Spina bifida (SB) is one of the most debilitating birth defects affecting the central nervous system with a prevalence of 3 in 10,000 live births [1]. While the prevalence has declined since the implementation of folic acid fortification, 1500 babies are born with spina bifida annually in the US. Spina bifida myelomeningocele (SBM) is the most severe and common form of SB. It is characterized by failure of neural tube development and atypical brain development [2]. The congenital defect consists of a cystic protrusion of the spinal cord through open vertebral arches resulting in motor paralysis and sensory loss below the level of the spinal lesion. Children born with this defect experience limited mobility secondary to paralysis of the lower extremities. Congenital malformations of the cerebellum, corpus callosum, and the midbrain commonly occur in SBM that further disrupt brain development [3].

Children with SBM present with a mixed pattern of strengths and weaknesses often within the same developmental areas. Sensory loss and motor paralysis of the trunk and lower extremities is dependent on the level of the spinal lesion. Mobility is impaired which affects the ability of the child to explore the environment. The child may need orthoses and an assistive device to walk. Major functional deficits are seen in movement, timing, and attention. Upper extremity impairments have also been recognized clinically for some time but have not been explained based on the underlying pathology of SBM [4-6]. Damage to the developing cerebellum could disrupt the establishment of the cortico-cerebellar circuits that support procedural learning, modulation of attention, and social skill acquisition. Understanding the functional deficits associated with the cerebellar malformations seen in SBM could assist in guiding early intervention strategies.

The cerebellum in children with SBM is structurally different from a typically developing child’s cerebellum. Some parts of the cerebellum are smaller and some parts are larger. Children with SBM exhibit significant reductions in cerebellum volumeas well as structural deficits [7,8]. The volume of the anterior lobe of the cerebellum is increased while the posterior lobe of the cerebellum is decreased. The anterior lobe is involved in motor function while the posterior lobe is part of the cognitive cerebellum.The cerebellum regulates motor output by comparing sensory information from the intended movement with the sensory information from the actual movement. Early motor learning depends on the cortico-striatal and cortico-cerebellar systems. In later motor learning only one of these systems is needed to consolidate and maintain memory for the new motor sequence.

The majority of children with SBM also have an Arnold-Chiari-II malformation (ACM), and exhibit hydrocephalus requiring placement of a ventriculoperitoneal shunt. ACM is a cranial malformation of the posterior cranial fossa. A small posterior fossa restricts the development of the cerebellum. In ACM, the size of the cerebellar hemispheres is reduced, causing the cerebellar vermis to be displaced downward, shifting the medulla and cervical cord downward and elongating the medulla [9]. Additional changes include tectal beaking (structural changes in the roof of the midbrain) and wrapping of the cerebellar hemispheres around the brainstem [10]. The size of the posterior fossa and consequently the volume of the cerebellum are reduced in children with SBM. Moreover, the reductions are not merely a linear down scaling. The anterior cerebellum enlarges while the posterior cerebellum is reduced. Cerebellar pathology plays a central role in causing the motor and perceptual findings in children with SBM [11].

The cerebellum is an important part of the neural network for procedural motor learning [12]. The anterior lobe of the cerebellum is intact and enlarged in children with SBM while the posterior lobe of the cerebellum is reduced [13]. The reduction of the posterior cerebellum produces deficits in the cognitive part of the cerebellum. The cognitive cerebellum involves spatial processing and visual working memory [14]. Changes in structure and underdevelopment of the cerebellum are prominent features in the neuropathology of SBM [2].

Cerebellar dysfunction has been documented in a wide variety of neurodevelopmental disorders ranging from autism spectrum disorder (ASD) [15], attention deficit hyperactive disorder (ADHD) to Joubert syndrome [16], a rare genetic disorder. Recent reviews have linked the cognitive, language, and social deficits exhibited by these children to cerebellar malformations [17,18]. Abnormalities of the cerebellum are routinely described in studies of children with ASD [19,20] and symptom severity has been correlated with a reduction in cerebellar volume [21]. Decreases in cerebellar gray matter have also been documented in different cerebellar sub regions depending on the neurodevelopmental disorder described.

Functional Deficits

Functional deficits are those that are always present in children with SBM and are apparent in infancy; persist in childhood, adolescence and adulthood. The three functional deficits are movement, timing and attention. All have been linked to the CNS damage that occurs with SBM [22]. They are all weakly correlated to each other but are definitely associated with structural changes in the brain. The variation in the magnitude of these functional deficits is thought to be related to the degree of structural changes in the cerebellum caused by ACM [11,23]. Because of the variation in functional deficits, children with SBM present with a mixed pattern of strengths and weaknesses often within the same areas. A summary of reviewed studies can be found in Table 1.

Citation: Martin S and Kitzman P. Evidence of Cerebellar Dysfunction in Children with Myelomeningocele. Phys Med Rehabil Int. 2017; 4(1): 1109. ISSN : 2471-0377