There is also research investigating whether high-throughput sequencing, wherein the investigator does not need to compare DNA results with known genomic sequences, could be used in specifically diagnosing unknown causes of viral meningitis.While there is some emerging evidence that bacterial meningitis may have a negative impact on cognitive function, there is no such evidence for viral meningitis. References


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Primary lateral sclerosis (PLS) is a very rare neuromuscular disease characterized by progressive muscle weakness in the voluntary muscles. PLS belongs to a group of disorders known as motor neuron diseases. Motor neuron diseases develop when the nerve cells that control voluntary muscle movement degenerate and die, causing weakness in the muscles they control. PLS only affects upper motor neurons. There is no evidence of the degeneration of spinal motor neurons or muscle wasting (amyotrophy) that occurs in amyotrophic lateral sclerosis (ALS). Symptoms and signs
Onset of PLS usually occurs spontaneously after age 50 and progresses gradually over a number of years, or even decades. The disorder usually begins in the legs, but it may start in the tongue or the hands. Symptoms may include difficulty with balance, weakness and stiffness in the legs, and clumsiness. Other common symptoms are spasticity (involuntary muscle contraction due to the stretching of muscle, which depends on the velocity of the stretch) in the hands, feet, or legs, foot dragging, and speech and swallowing problems due to involvement of the facial muscles. Breathing may also become compromised in the later stages of the disease, causing those patients who develop ventilatory failure to require noninvasive ventilatory support. Hyperreflexia is another key feature of PLS as seen in patients presenting with the Babinskis sign.