Outcome of acute seizures is more devastating in the aged population than in the young adults

(SciGuru.com) A new study suggests that acute seizures in the elderly population have much more devastating consequences than the effects of similar seizures in the young adult population. The study was conducted by scientists at the Durham Veterans Affairs Medical Center and the Duke University Medical Center at Durham, NC.

Using a rat model of status epilepticus (continuous unremitting seizure for prolonged period) and acute seizures, this study demonstrated that three hours of seizure activity in aged animals resulted in a much severe loss of neurons in the hippocampus, in comparison to young adult animals. The hippocampus is a region of the brain that is: (i) important for functions such as learning, memory and mood; (ii) most vulnerable to seizure-induced neuron loss; and (iii) believed to be the site of spontaneous seizure generation in temporal lobe epilepsy. Temporal lobe epilepsy, one of the most common types of epilepsy, evolves mostly after acute seizures resulting from stroke, head injury and infections.

Illustration of hippocampal damage after acute seizures

Acute seizures in this study induced chronic temporal lobe epilepsy, as revealed by repeated spontaneous seizures, in 100% of aged animals within the second month following acute seizures. In contrast, only 60% of young adult animals developed chronic temporal lobe epilepsy following acute seizures during a similar timeframe. In addition, aged animals that developed chronic epilepsy exhibited more frequent and severe spontaneous seizures than young adult rats that developed chronic epilepsy.

"This finding shows that the aged population has an increased tendency for developing chronic epilepsy following an episode of acute seizures, and the chronic epilepsy resulting from acute seizures is much severe in the aged than in the young adult population", Dr. Ashok K. Shetty, a professor at the Duke University Medical Center's Division of Neurosurgery and the senior author of this study told the online science news publication SciGuru.com.

The research was published by Dr. Shetty and colleagues in the February, 2011 issue of Aging and Disease, a peer-reviewed open access scholarly journal.

Aged animals that underwent acute seizures also developed severe learning impairments and hence were unable to form memory even after eleven sessions of training. Young adult animals, on the other hand, retained the ability for learning but failed to retrieve the memory at 24 hours after the learning sessions.

"This shows that, even after acute seizures, the young adult population can retain their ability for learning but might have problems with retrieval of the formed memory after a certain delay. In contrast, acute seizures in the aged population can impair the learning process itself and hence could make them incapable for making certain types of memory", said Dr. B. Hattiangady and Dr. R. Kuruba, co-authors of this study.

According to Dr. Shetty, "Early application of both anticonvulsant and neuroprotective treatments after the onset of acute seizures may be critical for decreasing both the duration of acute seizure activity and the resulting morbidity in the aged population. Aged population is generally more vulnerable to acute seizures due to a greater incidence of stroke, degenerative diseases, tumor, head injury and infections".

Epilepsy is a brain disorder characterized by recurrent seizures. Seizures are episodes of disturbed brain function that cause an involuntary change in body movement or function including change in attention or behavior. According to the Centers of Disease Control of the United States, epilepsy affects approximately 2.5 million people in the US alone.

A Merit Review Award from the Department of Veterans Affairs and a grant from the National Institute of Neurological Disorders and Stroke to Dr. Shetty supported this study.

Website of Dr Ashok Shetty at Duke: https://faculty.duhs.duke.edu/faculty/info?pid=2483

Publication: Acute Seizures in Old Age Leads to a Greater Loss of CA1 Pyramidal Neurons, an Increased Propensity for Developing Chronic TLE and Severe Cognitive Dysfunction
Bharathi Hattiangady, Ramkumar Kuruba and Ashok K. Shetty.
Aging and Disease Volume 2, Number 1; 1-17, 2011