By its very definition, the word palsy speaks of paralysis which may also be accompanied by involuntary movements, uncontrollable tremors or spasms. Whilst various types of palsy have been identified and categorised, cerebral palsy definition relates more pertinently to a specific set of neurological conditions which affect one or more aspects of motor function.
Four distinct types of cerebral palsy (CP)
The main cause of CP is a non-progressive brain lesion or injury which is acquired during a foetus’s development in the mother’s womb and in young babies and infants in their early childhood. In any such case, cerebral palsy definition is commonly recognised in four categories and these present differently due to the timing and location of the lesion within the brain, for example a lesion of the cerebral cortex, the basal ganglia or cerebellum, intraventricular haemorrhage (IVH Grades I-IV), periventricular leukomalacia (PVL) white matter changes usually associated with prematurity and meningitis. Whilst the lesion itself is non-progressive, the signs and symptoms can change through childhood and continue to cause difficulties into adulthood. The four types of cerebral palsy are spastic, athetoid or dyskinetic, hypotonic and ataxia and we will look at these in more detail next.
From prenatal brain haemorrhages and infections to a lack of oxygen during birthing and brain traumas, they can all be underlying causes of a resultant spastic CP condition. Visible symptoms can vary widely from mild muscle stiffness to more extreme effects in individual limbs or even to the whole of one side of the body.
Clinicians further classify spastic CP in three further categories including spastic diplegia which primarily affects the legs but may also have a minor impact on upper limb mobility. Another cerebral palsy definition category is spastic hemiplegia where movements on one side of the body are primarily affected, whilst spastic quadriplegia tends to affect the whole body including the face. Sufferers of the latter are also more likely to experience what is termed as “co-occurring” disorders which often include epilepsy.
Athetoid / Dyskinetic CP
In understanding something of the cerebral palsy definition of Choreoathetoid and Dyskinetic CP, its causation may be a useful place to start. Put in its simplest terms, the basal ganglia of the brain could be imagined as a kind of central switchboard which relays information for muscle movements down the spinal cord to the nerves and muscles. Damage to this area of the brain results in involuntary muscle movements that can range from small repetitive writhing movements, described as pure athetosis, to wider ranging movements of the limbs, recognised as choreoathetosis and to more extreme fluctuations in body and limb movements, and repetitive muscle spasms that can be painful. This last group is recognised as dystonic athetosis.
In contrast to the spastic hypertonus and dyskinetic forms of cerebral palsy described above, the hypotonic form has the opposite effect on muscles causing them to be “floppy” or relaxed (hypotonia). Poor or low muscle tone leads to difficulty in performing even the most basic motor functions. The most visible symptoms of hypotonic CP are instability, difficulty sustaining upright postures such as standing, and fatigue.
From blood clots and strokes to cranial infections and oxygen starvation, they may all be underlying causes of hypotonic cerebral palsy.
Pure Ataxia is less common and is usually seen in combination with spasticity or dyskinesia. It primarily arises from a lesion of the cerebellum, the area of the brain responsible for receiving sensory information and regulating movement. Damage to this area of the brain results in difficulties with balance and coordination, particularly walking, due to the role of the cerebellum in moderating force, direction and smoothness of movement. Patients with ataxia will often present with jerky movements and varying degrees of tremor. This is seen throughout the body and effects movement of the eyes (nystagmus) and speech.
Due to the nature of Cerebral Palsy, patients within all categories of CP often experience a number of secondary problems and associated difficulties. These include developmental delay; muscle contractures and postural deformity; breathing difficulties; feeding, drinking and swallowing difficulties; digestive problems; speech and communication difficulties; emotional regulation difficulties; learning difficulties and cognitive and behavioural difficulties including Autistic Spectrum Disorder and ADHD.
Understanding cerebral palsy definition for the most beneficial outcomes
Although, as yet, there is no cure for these conditions, understanding cerebral palsy definition and cause does lead to identifying the correct and most effective forms of treatment. Early detection and referral to specialist clinicians is also crucial and combined with the use of holistic and progressive therapies, such as MAES Therapy, have consistently shown to provide the most positive long-term outcomes.