Cerebrospinal fluid free-radical peroxidation products and cognitive functioning patterns differentiate varieties of normal pressure hydrocephalus.

The aims of the study were as follows: first, to verify the hypothesis that free radical peroxidation may be one of the factors implicated in pathophysiology of normal pressure hydrocephalus (NPH) and, second, to find out whether these biochemical characteristics together with neuropsychological cognitive deficits can differentiate between various types of NPH. This provides prognostic criteria for selection of patients for shunt surgery. Lipid peroxidation was measured in terms of thiobarbituric acid-reactive material (TBAR) and protein sulphydryl (SH) groups were measured as CSF content. Cognitive deficits were assessed using a number of neuropsychological tests. In the sample of NPH patients (n = 24), three categories were distinguished using these criteria: idiopathic active hydrocephalus (A), arrested hydrocephalus (AH), and post-traumatic hydrocephalus (PT). TBAR levels for NPH patients were higher than that of controls without CNS pathology (n = 2). Moreover, NPH patients had increased levels of total and soluble protein groups, and decreased levels of protein SH groups, which suggests the occurrence of processes that activate peroxidation of free radicals in normal pressure hydrocephalus. Levels of these indicators varied across NPH types. Two categories of NPH patients, with active (A) or posttraumatic (PT) hydrocephalus differed significantly from the controls (C)--their TBAR levels were 0.58, 0.56 and 0.28 nmol/mg protein, respectively; soluble SH levels: 41.5; 58.15 and 11.3 nmol/mg protein, and protein SH levels: 34.3, 21.8 and 57.5 nmol/mg protein. In PT group, many individual differences were noticed. These findings seem promising because the studied biochemical indicators may serve as additional diagnostic criteria for selection of NPH patients for shunting.