In bacterial meningitis it is typically lower; the CSF glucose level is therefore divided by the blood glucose (CSF glucose to serum glucose ratio). A ratio ≤0.4 is indicative of bacterial meningitis; in the newborn, glucose levels in CSF are normally higher, and a ratio below 0.6 (60%) is therefore considered abnormal. High levels of lactate in CSF indicate a higher likelihood of bacterial meningitis, as does a higher white blood cell count. If lactate levels are less than 35 mg/dl and the person has not previously received antibiotics then this may rule out bacterial meningitis.Various other specialized tests may be used to distinguish between different types of meningitis. A latex agglutination test may be positive in meningitis caused by Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, Escherichia coli and group B streptococci; its routine use is not encouraged as it rarely leads to changes in treatment, but it may be used if other tests are not diagnostic. Similarly, the limulus lysate test may be positive in meningitis caused by Gram-negative bacteria, but it is of limited use unless other tests have been unhelpful. Polymerase chain reaction (PCR) is a technique used to amplify small traces of bacterial DNA in order to detect the presence of bacterial or viral DNA in cerebrospinal fluid; it is a highly sensitive and specific test since only trace amounts of the infecting agents DNA is required.
The Attitude Towards Heights Questionnaires (ATHQ) and Behavioural Avoidance Tests (BAT) are also used.However, acrophobic individuals tend to have biases in self-reporting. They often overestimate the danger and question their abilities of addressing height relevant issues. A Height Interpretation Questionnaire (HIQ) is a self-report to measure these height relevant judgements and interpretations. The Depression Scale of the Depression Anxiety Stress Scales short form (DASS21-DS) is a self report used to examine validity of the HIQ. Treatment
Traditional treatment of phobias is still in use today. Its underlying theory states that phobic anxiety is conditioned and triggered by a conditional stimulus. By avoiding phobic situations, anxiety is reduced. However, avoidance behaviour is reinforced through negative reinforcement. Wolpe developed a technique called systematic desensitization to help participants avoid "avoidance". Research results have suggested that even with a decrease in therapeutic contact, densensitization is still very effective. However, other studies have shown that therapists play an essential role in acrophobia treatment. Treatments like reinforced practice and self-efficacy treatments also emerged.There have been a number of studies into using virtual reality therapy for acrophobia. Botella and colleagues and Schneider were the first to use VR in treatment. Specifically, Schneider utilised inverted lenses in binoculars to "alter" the reality. Later in the mid-1990s, VR became computer-based and was widely available for therapists. A cheap VR equipment uses a normal PC with head-mounted display (HMD). In contrast, VRET uses an advanced computer automatic virtual environment (CAVE).