Functional seizures
The central idea of the first model is that functional seizures result from a process of dissociation, where memories and/or mental functions are psychologically split from consciousness, and thus strongly resemble the phenomena of post-traumatic reliving. Functional seizures are thought to represent sensorimotor flashes that occur when dissociative material resulting from a past traumatic event invades consciousness, usually in response to a traumatic reminder from the environment. The individual consequently misinterprets it as a seizure, as there is only awareness of fragments of the dissociated material, and its links to the traumatic event are not recognised, or the individual is able to recognise it but is either unwilling or unable to articulate it in a way that does not result in a dissociative seizure.
MODEL 1: Functional seizures are caused by activation of the dissociation process
MODEL 2: Functional seizures are a learned biological response
Functional seizures are thought to represent an acute and highly automatic behavioural response, as a result of a response to a threat and/or an alteration of arousal, aimed at protecting the organism and regulating arousal in a way that returns to homeostasis. Acute arousal is thus thought to irritate the dissociative state, characterised by emotional numbing, depersonalisation-derealisation and other aspects that characterise non-epileptic seizures.
MODEL 3: Functional seizures are a manifestation of emotional distress
Functional seizures are a defence mechanism whose function is to express emotional distress. Thus, non-epileptic seizures either represent physical components of emotional states that individuals are unable to recognise or misinterpret because they have not developed the ability to identify and/or name their emotional states (Read more).
MODEL 4: Functional seizures are the result of learned behaviour
Functional seizures represent habitual behaviour that is maintained by the process of learning through conditioning (either positive or negative reinforcement) or by intrinsic or extrinsic benefits (either primary or secondary benefits). Functional seizures can also develop as a result of model learning (a family member has had or is having seizures).
Integrative Cognitive Model (ICM)
The integrative cognitive model assumes that the observed and subjective elements of functional seizures are the result of the automatic execution of learned mental representations of seizures (seizure scaffolding), which are executed in the context of high-level inhibitory dysfunctions as a consequence of chronic stress.
The seizure stage consists of a sequence of sensations and motor activities. These can form:
Physical symptoms (e.g. dissociation, hyperventilation, head injury)
Intrinsic reflexes such as freezing (sympathetic nervous system response)
Knowledge gained and learning by imitation
While perceptions can be triggered by sensory inputs, they are primarily created on the basis of pre-existing expectations and consequently do not reflect the individual's real internal or external environment. The stage of the seizure is not fixed, but is nevertheless relatively stable and resembles a conditioned response.
Stage fits can be triggered by a range of internal and external stimuli. It is mostly triggered in response to increased autonomic arousal, although it can also be triggered in its absence, in response to relatively neutral emotional and cognitive stimuli. The individual experiences it as involuntary, and thus deliberately submits to the dissociation that results from a functional seizure. Active inhibition is thus withdrawn, although there is a possibility that individuals begin to perceive it as voluntary (Reuber and Brown, 2017).
Advantages and disadvantages of the models
(adapted from Brown and Reuber, 2016)
-
Benefits
The model explains the increased level of childhood trauma in patients with functional seizures and confirms the clinical relevance of traumatic events in the treatment of patients
Explains perceived 'involuntary' seizures, unusual motor activity and potential loss of consciousness
It explains elevated scores on questionnaires measuring dissociation as a trait.
Restrictions
Many patients do not report a history of potentially traumatic events
Only a minority of patients meet the criteria for PTSD
Mixed results on questionnaires that measure dissociation as a trait; there may also be different aspects of dissociation that are not measured by these questionnaires
Some patients do not report significant dissociative flashes
Findings on suggestibility are mixed
-
Benefits
Explains the phenomenology and semiology of seizures
Explains why many patients report autonomic arousal without explicitly stated anxiety (i.e. panic without panic)
Panic without panic is consistent with ictal unreality and dissociation in patients with functional seizures
The dissociation property is elevated in patients with functional seizures
Disadvantages
There are large intra- and inter-individual differences between individuals, suggesting that they need not be a purely stereotypical, biologically hardened phenomenon
Panic without panic does not explain why patients perceive a seizure as involuntary, loss of consciousness, unusual motor activity or unresponsiveness.
Many functional seizures can also occur in response to neutral cognitive and emotional stimuli, in the absence of arousal of the autonomic nervous system.
-
Benefits
Explains the discrepancy between physical symptoms indicating increased arousal and low explicit anxiety
Consistent with the results of neuroscientific studies (avoidant behaviour, deficits in emotional processing and regulation, alexithymia)
Disadvantages
It does not explain semiology and phenomenology
Neuroscience studies are not fully consistent and have statistical weaknesses (e.g. small sample sizes, population heterogeneity)
Many individuals deny emotional problems
-
Benefits
Explains unresponsiveness and motor activity in some patients
The model is supported by the increased prevalence of patients diagnosed with functional seizures who were also previously diagnosed with epilepsy
Explains the link between functional seizures and previous injury/illness/loss of consciousness.
Disadvantages
Indicates voluntary and deliberate simulation
It does not explain the similarities in the characteristics of attacks between different cultures
It is difficult to explain the onset of symptoms
-
An exclusively psychological model
It lacks an anatomical or mechanistic explanation
Functional seizures are the result of dysfunction in the structure and functional connectivity of many brain networks, allowing the model to be individualised
-
Reuber, M., and Brown, R. J. (2017). Understanding psychogenic nonepileptic seizures-Phenomenology, semiology and the Integrative Cognitive Model. Seizure, 44, 199-205. doi:10.1016/j.seizure.2016.10.029
Brown, R. J., and Reuber, M. (2016). Psychological and psychiatric aspects of psychogenic non-epileptic seizures (PNES): A systematic review. Clinical Psychology Review, 45, 157-182. doi:10.1016/j.cpr.2016.01.003
Brown, R. J., and Reuber, M. (2016). Towards an integrative theory of psychogenic non-epileptic seizures (PNES). Clinical Psychology Review, 47, 55-70. doi:10.1016/j.cpr.2016.06.003