Motor Deficits

All brain injuries are unique depending on the location(s) of the injury within the brain. Impairments can result which may be permanent or temporary and may also cause partial or total disability.

Brain injury can affect gross and fine muscle movements. Gross motor movements are large muscle movements as seen in muscle use during exercise or sporting activities. Fine motor movements are movements requiring dexterity and small very well controlled movements e.g. threading a needle.

The brain is ‘wired’ so that damage to the left side of the brain can cause motor deficits on the right side of the body, and damage to the right side of the brain can cause motor deficits on the left side of the body.

Muscle wasting otherwise known as atrophy can occur following an acquired brain injury and consequent loss of muscle function. Although a muscle itself may be undamaged, if it is not being stimulated by the nerves arising from the brain it will waste away. Physiotherapy and continued use of the muscle where possible is therefore important to prevent muscle wasting.

Paralysis

Paralysis can occur if a part of the brain that controls specific muscles is damaged as a result of acquired or traumatic brain injury involving the motor system. Paralysis is defined as a loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory damage as well as motor damage.

Abnormal Muscle Tone

Muscle tone (residual muscle tension or tonus) is a continuous and passive partial contraction of the muscles. Both extensor and flexor muscles (which act against each other), are involved in the maintenance of a constant tone while at rest. In skeletal muscles, this helps maintain a normal posture.

An acquired brain injury involving damage of motor neurons can result in abnormal muscle tone which can involve a state of low muscle tone (Hypotonia,) or a high muscle tone (Hypertonia).

Hypotonia, is also commonly known as floppy baby syndrome. It is a state of low muscle tone, often involving reduced muscle strength. Recognizing hypotonia, even in early infancy, is usually relatively straightforward. The long-term effects of hypotonia on a child’s development depend on the severity of the muscle weakness. The principal treatment for hypotonia is physical therapy, occupational therapy for remediation, and/or music therapy.

Hypertonia is sometimes also referred to as spasticity. Damage within the brain may result in muscle spasms, stiffening or straightening out of muscles, or shock like contractions of all or part of a muscle group. Rigidity is a severe state of hypertonia. Physiotherapy has been shown to be effective in controlling hypertonia through the use of stretching aimed to reduce motor neuron excitability. Medicines can also be used to reduce spasticity.

Ataxia/Co-ordination

Ataxia is a term for a group of disorders, including acquired brain injury that affect co-ordination, balance and speech. Any part of the body can be affected, but people with ataxia often have difficulties with:

• balance and walking
• speaking
• swallowing
• tasks that require a high degree of control, such as writing and eating
• vision

The exact symptoms and their severity vary depending on the type of ataxia a person has.

Treatment may include:

• speech and language therapy to help with speech and swallowing problems
• physiotherapy to help with movement problems
• occupational therapy to help cope with the day-to-day problems
• medication to control muscle, bladder, heart and eye problems