Cognitive Ability

The majority of leukodystrophies are likely to have an effect on cognitive ability (i.e. the capacity for intellectual activity such as thinking, reasoning and remembering).  Depending on the condition, people with some leukodystrophies may never develop normal cognitive ability, or may lose ability that they previously had. Some conditions will have a larger effect than others, and there will also be differences within conditions based on age of onset and other factors. In some conditions, such as some forms of ALD, cognitive ability can be unaffected.

Slowing or halting loss of cognitive ability is a strong priority for those with leukodystrophy and their loved ones. Unfortunately, in the majority of cases where it occurs, deterioration of cognitive ability caused by leukodystrophy is permanent and progressive. For some conditions (Adrenoleukodystrophy, Metachromatic Leukodystrophy) there are treatments that can prevent deterioration before it starts, or stop or slow down further deterioration. But deterioration that has already happened cannot be reversed.

Loss of cognitive ability in a loved one can be difficult and demanding for those caring for someone with a leukodystrophy. Mental health support should be considered for parents, partners and carers, and for the affected individual if appropriate. Please also see our information on respite and support for siblings.

Problems with cognitive ability typically start in different age groups depending on the condition.


Infants affected by cognitive problems either do not develop the usual cognitive skills, or lose skills they have acquired. Signs of cognitive difficulties may include irritability, feeding difficulties, disturbed sleep, and failure to develop psychomotor skills (i.e. ability at physical tasks like feeding or grasping) and coordination. It’s important to remember that irritability and problems with feeding or sleeping are common issues with babies whether or not they have a leukodystrophy, and are not automatically signs of cognitive problems.

Cognitive problems in infants with leukodystrophies are normally permanent and progressive. However, in Leukoencephalopathy with thalamus and brainstem involvement and elevated lactate, some improvement in cognitive ability may be seen over time.


Children with cognitive disabilities that began in infancy may continue to experience deterioration of their abilities. In some conditions, children initially develop normally but begin to lose cognitive skills at some time in childhood or adolescence. The onset of cognitive deterioration often causes changes in behaviour or personality, and increasing difficulties with school work. In some leukodystrophies the cognitive deterioration progresses until the child is left profoundly disabled. In other conditions  the deterioration may be less severe.

As children become adults, they will move from children’s (paediatric) health and other services to adult services. This process may begin when the child is as young as 14, but may be as late as 24 in some cases. See our transition information page for more details.


Some people with leukodystrophies will begin to experience cognitive deterioration in adulthood.

Memory loss is a common symptom of declining cognitive ability. Someone experiencing memory loss may forget the reality of what they are going through, causing periods of calm followed by panic as this information is remembered or reintroduced.

Severe cognitive deterioration and memory loss is known as dementia. People with dementia become increasingly dependent on others for personal care and wellbeing. Early signs of dementia include problems with language and judgement, disorientation, and difficulties with familiar tasks. In certain conditions, dementia can be triggered by a stroke (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy; Cerebral Autosomal Recessive Arteriopathy with Subcortical Infarcts and Leukoencephalopathy).

People with memory loss or dementia will need increasing amounts of support to perform everyday tasks. Helping someone with mild memory loss or the early stages of dementia to maintain their social life and continue with activities they enjoy can make a big difference to their sense of independence and self-confidence.

Mental Health and Psychiatric Problems

For adults and older children experiencing the beginnings of this process, the thought of losing cognitive ability can be terrifying. This can have a severe effect on mental health (link to mental health services), including depression and suicidal tendencies.

Personality changes, including increased tendency for aggressive behaviour, may occur in people experiencing cognitive deterioration. This can affect relationships and lead to increased isolation and vulnerability. Loss of judgement, loss of social inhibitions, poor concentration and loss of reasoning abilities all heighten this vulnerability and strain on relationships. Talking to people who understand this can be of great help. At Alex TLC we offer one-to-one support and peer support to individuals and families affected by dementia as a result of leukodystrophies.

Psychosis and hallucination can be an effect of cognitive changes in children and adults with some leukodystrophies (Alpha-Mannosidosis; Cerebrotendinous Xanthomatosis; Metachromatic Leukodystrophy). Schizophrenia is a possible consequence of Methylenetetrahydrofolate Reductase Deficiency, which may begin in childhood or adulthood. Mental health services can help with these conditions, through psychological treatments such as Cognitive Behavioural Therapy (CBT) or antipsychotic medication. For schizophrenia, Crisis Response Teams can be called out to help with acute incidents.