Periventricular leukomalacia is a condition which is usually associated with premature babies and belongs under the umbrella term cerebral palsy. Cerebral palsy is a condition in which there is some impairment to the brain’s ability to control movement and posture. Whilst movement and posture are both affected by muscles, in people with cerebral palsy, the problem lies not with the muscles themselves, but rather within the brain. This is due to abnormalities within the brain that affect its ability to control the muscles.
Cerebral palsy can arise due to abnormal development of the brain in utero, or a brain injury incurred before, during or after birth. The damage is irreparable and usually results in permanent disability, although the severity of the disability is variable, ranging from mild to severe.
Effects on the Brain
The human brain is composed of two types of tissue; white matter and grey matter. White matter represents about 60% of brain tissue with grey matter making up the remaining 40%. Whilst the brain typically represents about 2% of body mass, it uses 20% of the body’s oxygen supply and 20% of the blood supply. If brain cells are deprived of oxygen for more than 3 to 5 minutes, brain damage is likely to occur.
The term “periventricular” simply means around the ventricles of the brain. The ventricles are hollow chambers filled with cerebrospinal fluid which supports the tissues of the brain. In periventricular leukomalacia, the white matter of the brain has been damaged. This tissue is responsible for transmitting signals within the brain and to the rest of the body. In people with this condition, the white matter appears to be peppered with tiny holes. These holes interfere with the normal transmission of nerve signals passing through the tissue. Research has shown that these voids fill with cerebrospinal fluid.
The condition can be caused by certain infections picked up by the mother or the fetus and the child is particularly vulnerable between weeks 26 and 34 of gestation. The condition may also arise due to injury during this period of vulnerability. As a result of damage to the white tissue, the damaged nerve cells cause the muscles to become spastic, or tight, and resistant to movement (particularly in the legs). It may be the case that the symptoms do not become apparent until the child is a few months old.
Diagnosis And Therapy
Diagnosis is made with a combination of cranial ultrasound and magnetic resonance imaging techniques. The incidence of of the condition is higher in premature infants than their full-term counterparts. Between 4% and 20% of very low birth weight premature babies have the condition, and it is the principal form of brain injury sustained in these children. Up to three quarters of premature babies that do not survive, show evidence of the condition at autopsy.
Whilst there is no treatment for this condition, people can benefit from physiotherapy, speech therapy, occupational therapy and special education programmes. The outcomes will depend on the severity of the disability that the child sustained at the very start of life.
- Cerebral Palsy, National Institute of Neurological Disorders and Stroke: https://www.ninds.nih.gov/disorders/cerebral_palsy/detail_cerebral_palsy.htm
- Children’s Hospital of Wisconsin, Periventricular Leukomalacia: https://www.chw.org/display/PPF/DocID/22508/router.asp
- Brain Volumes in Adult Survivors of Very Low Birth Weight: A Sibling-Controlled Study, Fearon P. et al, PEDIATRICS Vol. 114 No. 2 August 2004, pp. 367-371
- Early Detection Of Periventricular Leukomalacia By Diffusion-Weighted Mr Imaging Techniques: https://www.spl.harvard.edu/archive/spl-pre2007/pages/papers/inder/earlydet/earlydet.html
- Periventricular Leukomalacia, Healthline: https://www.healthline.com/galecontent/periventricular-leukomalacia