Epilepsy and cognition – A bidirectional relationship?

Abstract

Cognitive comorbidities are very common in epilepsy and often seen as secondary to epilepsy or caused by epilepsy. The implicit and sometimes explicit assumption is that epilepsy (i.e. having seizures) damages the brain and thus leads to functional deterioration and behavioral alterations. This article highlights the historical background surrounding this viewpoint which is characterized by old reports on 'epileptic dementia' and the fact that most cognitive research in chronic epilepsies is done retrospectively. The central question of the present article is whether there is a bidirectional relationship between epilepsy and cognition. In this regard it is essential to disentangle what is the disease and what is the symptom. Cognitive problems often exist from the onset of epilepsy, if not before, and the impact of epilepsy on cognition cannot be discerned without also considering the underlying brain pathology and its dynamics. Unraveling the etiologies of epilepsy increasingly reveals conditions wherein epilepsy, cognitive and behavioral problems are all symptoms of a common underlying pathological condition. Functional reserve capacities determine the outcome of epilepsy and its treatment. A functional interrelationship exists between epilepsy and behavior, since epileptic activity can affect behavior and behavior can alter epileptic activity. In conclusion, an epilepsy-centric unidirectional view of the behavioral problems being caused by epilepsy is obsolete. Such a view may even prevent the search for and treatment of the underlying etiological factors. Instead a practical clinical approach is favored according to which the comorbidities of epilepsy must be diagnosed at the onset of the disease, and according to which comorbidities may require separate treatment approaches.

Challenges in epilepsy—The perspective of Norwegian epilepsy patients

“…in PWE, 20 with recurring tonic-clonic seizures particularly associated with a decline in cognitive function. 20…”

No proof of a causal relationship between antiepileptic drug treatment and incidence of dementia. Comment on: Use of antiepileptic drugs and dementia risk—An analysis of Finnish health register and German health insurance data

“…Many patients with epilepsy, because of their seizures or underlying pathologies, may fulfill psychometrically the criteria of a mild cognitive impairment. However, there is no evidence that a dementing mental decline occurs as a result of having seizures or seizures being treated . If there is progressive cognitive decline, there should be an underlying pathological condition causing it.…”

“…However, there is no evidence that a dementing mental decline occurs as a result of having seizures or seizures being treated. 10,11 If there is progressive cognitive decline, there should be an underlying pathological condition causing it. It is clear that in these cases differential diagnosis is challenging and misdiagnoses of dementia can easily occur.…”

Future directions in recognizing and dealing with the first seizure presentation – Research and operational issues

“…In this context, the neurobehavioral assessment of patients presenting with a first seizure or in the early stages of epilepsy is showing promise [11,12], these issues, [13]. There is increasing evidence that brain function is already compromised at the time of first seizure occurrence [14], with evidence of cognitive disturbances and neuropsychiatric issues which may be very subtle or more severe.…”

“…Unfortunately, there is only a limited number of welldesigned longitudinal studies so far. Evidence is particularly lacking in adult patients [13,11]. However, the findings that are available support the interpretation of a PFS as the "tip of the iceberg" [1] and the call for a search for new "clinical" biomarkers.…”