EEG is a safe, inexpensive, mobile test that can be integrated with the neurologic clinical examination and other testing to help physicians move more quickly and accurately to the right branch of the differential diagnostic tree even when the EEG result is not specifically diagnostic itself As technology evolves to allow faster; easier electrode application and remote transmission of EEG data to electroencephalographers; the use of EEG in the emergency room and intensive care units to assist with differential diagnosis is likely to sharply increase. We examine some differential diagnostic scenarios and actual cases where EEG proved useful. Neurologists are trained to think in differential diagnostic terms. As they review EEG tracings, they often ask neurodiagnostic technologists questions pertaining to the patient history or other testing results that help them assimilate the relevant differential diagnostic data. Neurodiagnostic technologists have a unique opportunity to collect useful differential diagnostic information because they spend about 20 minutes talking with the patient as they apply electrodes and they see the EEG results while the patient, family members, or the patient's nurse is still available for questioning. Those technologists who are able to see the bigger picture and think in differential diagnostic terms as they do EEG testing are more likely to include in their patient's history important clinical details that will help the neurologist reach the correct diagnosis of the patient.
Lambda waves are physiological, triangular shaped, sharp transients occurring over the occipital regions when eyes are open. Lambda waves occur with saccadic eye movements during visual scanning, disappearing when eyes are closed and in sleep. They are best elicited when subjects visually scan a complex picture, therefore seen during visual exploration of a brightly illuminated object or room. The expression of these waveforms seems to be secondary to a functional activation of a common region in the brain, probably localized within parieto-occipital region.
Tuberous Sclerosis Complex (TSC) is an inherited disorder resulting from mutations in one of two tumor suppressor genes: TSC1 (hamartin) and TSC2 (tuberin). Hamartin and tuberin, the protein products of TSC1 and TSC2, form a functional protein complex in the mTOR pathway that controls cell growth and proliferation. Epilepsy is the most common disorder in TSC, frequently associated with intractable and early onset seizures, and often as infantile spasms. Epilepsy surgery is an option for TSC patients with medically intractable epilepsy. Multimodality neuroimaging has improved the detection of epileptogenic foci, allowing an increased number of TSC patients to be evaluated noninvasively for resective surgery. Advances in understanding of the molecular pathogenesis of the TSC are crucial to establish new therapeutic approaches for individuals with TSC.