Olfactory auras are not necessarily unpleasant. The amygdala is the most likely symptomatogenic zone of olfactory auras. Tumors are the commonest etiology; mesial temporal sclerosis is a relatively rare cause.

The elderly are generally defined as those over 60 or 65 years old, but they are a heterogeneous group and may be subdivided into categories based on age and health status. The incidence of epilepsy is highest in the elderly. With a progressive increase in life expectancy, this is the fastest growing segment of patients with epilepsy. Older patients most often have focal seizures, with less prominent auras and automatisms, and longer duration of postictal confusion compared to younger patients. Status epilepticus is common and has a high mortality. The most common specific etiology is cerebrovascular disease, but the cause remains unknown in many patients. Diagnosis can be challenging because of several patient-related, physician-related and investigation-related factors. Over-diagnosis and under-diagnosis are common. Treatment is complicated by the presence of physiological changes related to aging, co-morbidities and cognitive problems as well as concerns regarding drug interactions and medication adherence. Seizures can be controlled in most patients with low doses of a single anti-epileptic drug (AED). Tolerability is an important factor in selection of an AED, as elderly patients tend to be highly sensitive to side effects. Drug-resistant epilepsy is uncommon. Epilepsy surgery, especially temporal lobectomy, can be performed in older patients with good results. More studies addressing the pathophysiological mechanisms of epilepsy in this age group, and greater inclusion of the elderly in clinical trials, as well as development of comprehensive care models are needed to provide optimal care to these patients.

Summary: Montages are logical, orderly arrangements of electroencephalographic derivations or channels that are created to display activity over the entire head and to provide lateralizing and localizing information. Most often, bipolar and referential montages are used for routine electroencephalographic recordings. Common average and Laplacian montages can also be helpful in some situations. Because each type of montage has certain strengths and limitations, the ACNS guidelines recommend the use of multiple classes of montages for each electroencephalographic recording. A variety of factors need to be considered for localization by scalp electroencephalogram, but in clinical practice, a three-step approach can be used to localize an interictal epileptiform discharge by visual inspection using a standard set of scalp electrodes and conventional montages. The ACNS guideline provides a number of standard and suggested montages, but, depending on the clinical situation, additional montages can be designed using the electrodes within the 10-20 system or by placing additional electrodes.

Numerous cases of severe and life-threatening hyperammonemia (HA) related to the treatment of epileptic seizures with valproic acid (VPA) have been previously reported in the medical literature. The aim of this prospective, multicenter study was to verify the putative association between T1405 polymorphism and occurrence of VPA-induced HA in the cohort of 142 adult Caucasian patients with epilepsy treated with VPA for at least 1 year and with normal liver functions. The nonsynonymous T1405N polymorphism genotyping was performed by real-time TaqMan PCR genotyping. In addition to plasma ammonia level, concentrations of liver enzymes and total VPA were measured in plasma with standard laboratory methods. HA (defined as ammonia plasma level >65 μmol/L) was observed in total of 11 (7.7%) of patients treated with VPA, and the carrier status for the investigated polymorphism was significantly (P = 0.009, odds ratio 5.4 with 95% confidence interval of 1.58–18.43) associated with the occurrence of HA. The results of this study support a notion that in the Caucasian patients with epilepsy undergoing VPA therapy, a T1405N (4217C > A, rs1047891) nonsynonymous variant was a significant risk factor for the occurrence of HA, even in patients with normal plasma levels of VPA.