Why there is an unexpected decline in cognition after epilepsy surgery

In people with severe epilepsy, surgical intervention is often the only treatment – often with great success
.
While neuropsychological manifestations can recover in the long term after successful surgery, in rare cases, there can be an unexpected decline
in cognitive performance.
Researchers at the University of Bonn have now been able to show which patients are particularly at high risk for the disease
.
Their findings were published in the journal Annals of Neurology
.
They can help identify those who
should avoid surgery.
Instead, new prospects for treatment targeting these patients are emerging
.

Epilepsy cannot always be controlled
with medication.
In this case, the patient should consult whether surgery
is an option.
During surgery, surgeons selectively remove the damaged brain tissue
that caused the seizures.
This usually provides a complete cure
for the patient.

Dr.
Juri-Alexander Witt, a neuropsychologist from the Department of Epilepsy at Bonn University Hospital, explains: "Surgery has revolutionized the treatment
of severe epilepsy.
" "However, epilepsy surgery always carries the risk of
cognitive decline.
That said, long-term studies have shown that brain function can be restored
in the long term after successful surgery.
”

Performance declined unexpectedly in the months after surgery

However, in a small percentage of patients, unexpected performance degradation
does not occur until months or years after surgery.
"We wanted to know the reason behind this," said
Annika Lance, a doctoral student at the Institute of Neuropathology in Professor Albert Becker's research group.

University Hospital Bonn's extensive experience in epilepsy surgery has helped researchers: they were able to draw on brain tissue samples
taken decades ago.
"In total, we analyzed 24 samples from men and women diagnosed with severe cognitive decline months or even years after surgery," Reimers
explains.

In the process, the researchers made a surprising discovery: In those affected patients, the removed tissue was destroyed by a secondary disease at the time of surgery — either inflammation or early Alzheimer's-like dementia
.
Becker, who is also a member of the Interdisciplinary Research Area (TRA), said: "With these pre-existing diseases, the body's defenses are particularly active
.
" "The trauma of the surgery may further stimulate the immune system in the brain to attack healthy brain tissue
.
”

Examinations can guide when surgery should be avoided

The researchers now plan to study samples from other epilepsy centers to confirm their findings
.
The findings may help identify those patients
who should avoid surgery.
Dr.
Juri-Alexander Witt emphasizes: "We currently have a wide variety of diagnostic methods that can be used for this purpose
.
"

For example, all patients complete a series of psychological tests before surgery to determine their cognitive performance
.
When taking into account brain scanner images and examination of cerebrospinal fluid by lumbar puncture, some results already allow conclusions to be drawn
about concomitant diseases.
"If these tests indicate an onset of inflammation or neurodegenerative disease, entirely new treatment options, such as anti-inflammatory drugs, will emerge, which may make surgery unnecessary
," Baker said.

Subsidize:

The research was funded
by the German Research Foundation (DFG) and the Else Kröner-Fresenius-Foundation within the framework of the PhD program in Neuroimmunology.

Journal Reference:

1. Annika Reimers, Christoph Helmstaedter, Christian E.
   Elger, Julika Pitsch, Motaz Hamed, Albert J.
   Becker, Juri‐Alexander Witt.
   Neuropathological insights into unexpected cognitive decline in epilepsy.
   Annals of Neurology, 2022; DOI: 10.
   1002/ana.
   26557