Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed.

Truncal ataxia is a sign of ataxia characterized by instability of the trunk. It usually occurs during sitting.

The presence of atrophy (wasting) of the corpus callosum.

Incapability to ambulate.

Cerebellar atrophy is defined as a cerebellum with initially normal structures, in a posterior fossa with normal size, which displays enlarged fissures (interfolial spaces) in comparison to the foliae secondary to loss of tissue. Cerebellar atrophy implies irreversible loss of tissue and result from an ongoing progressive disease until a final stage is reached or a single injury, e.g. an intoxication or infectious event.

Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.

The presence of cerebellar signs and symptoms such as lack of balance associated with quadrupedal gait (locomotion on all four extremities with a 'bear-like' gait with the legs held straight).

Atrophy of the cortex of the cerebrum.