More white matter damage leads to more severe cerebral palsy; different subtypes are identified and diagnosed by a neurologist. Despite the varying grades of PVL and cerebral palsy, affected infants typically begin to exhibit signs of cerebral palsy in a predictable manner. Typically, some abnormal neurological signs (such as those previously mentioned) are visible by the third trimester of pregnancy (28 to 40 weeks after conception), and definitive signs of cerebral palsy are visible by six to nine months of age. Epilepsy
Another common but severe outcome of PVL patients is the development of epilepsy. The link between the two is not entirely clear; however, it appears that both genetic and early environmental factors are involved. One study estimated that 47% of children with PVL also have epilepsy, with 78% of those patients having a form of epilepsy not easily managed by medication. Many of these affected patients exhibit some seizures, as well as spastic diplegia or more severe forms of cerebral palsy, before a diagnosis of epilepsy is made. Frequency
Unfortunately, there are very few population-based studies on the frequency of PVL. As previously described, the highest frequency of PVL is seen in premature, very low birth weight infants. These infants are typically seen in the NICU in a hospital, with approximately 4-20% of patients in the NICU being affected by PVL. On a large autopsy material without selecting the most frequently detected PVL in male children with birth weight was 1500-2500 g., dying at 6–8 days of life.
Future treatments
Although no treatments have been approved for use in human PVL patients, a significant amount of research is occurring in developing treatments for protection of the nervous system. Researchers have begun to examine the potential of synthetic neuroprotection to minimize the amount of lesioning in patients exposed to ischemic conditions. Prognosis
The prognosis of patients with PVL is dependent on the severity and extent of white matter damage. Some children exhibit relatively minor deficits, while others have significant deficits and disabilities. Minor tissue damage
Minor white matter damage usually is exhibited through slight developmental delays and deficits in posture, vision systems, and motor skills. Many patients exhibit spastic diplegia, a condition characterized by increased muscle tone and spasticity in the lower body. The gait of PVL patients with spastic diplegia exhibits an unusual pattern of flexing during walking. Progression
Those patients with severe white matter injury typically exhibit more extensive signs of brain damage. Infants with severe PVL suffer from extremely high levels of muscle tone and frequent seizures. Children and adults may be quadriplegic, exhibiting a loss of function or paralysis of all four limbs. Cerebral palsy
Many infants with PVL eventually develop cerebral palsy. The percentage of individuals with PVL who develop cerebral palsy is generally reported with significant variability from study to study, with estimates ranging from 20% to more than 60%. One of the reasons for this discrepancy is the large variability in severity of cerebral palsy. This range corresponds to the severity of PVL, which can also be quite variable.