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The Interface of Epilepsy and Psychiatry: Diagnostic Issues

VERNON M NEPPE MD, PhD(Med)

Poetic history

  • Epilepsy, the neurologic: the "Falling Sickness" of the Middle-ages;
  • Epilepsy, the religious: The "Sacred Disease" of Hippocrates;
  • Epilepsy: the anthropologic - Pre-literate cultures' special communication with the Supreme Being via indigenous healers;
  • Epilepsy, the psychiatric with Kraepelinian "epileptic insanity", and Pinel's link with " lunatic asylums ";
  • Epilepsy, the psychologic with the rigid, irritable "epileptic personality";
  • Epilepsy: the linguistic with ancient Japanese derivations of seizures and psychosis being similar.
  • The past has taught us a great deal about what seizures are not.
  • However, today in psychiatry, a great void exists with regard to seizures: DSM 4 does not address the links of seizures and psychiatry. In DSM 3 R we had the non-specific and diagnostically inadequate and inaccurate conditions of organic delusional disorder, atypical psychosis, organic hallucinosis or organic mood disorder. In DSM IV, we have "symptomatic disorders" and "mental disorders due to a general medical condition" with seizures having no special pride of place. Epilepsy has remained a predominantly neurologic and not psychiatric condition and the limited numbers of psychiatric epileptologists worldwide have not allowed this situation to correct itself.

    When is someone epileptic?

    A person is only epileptic when he has seizures recurrently. An epileptic seizure involves paroxysmal cerebral neuronal firing producing clinically relevant changes. Such seizures may or may not produce disturbed consciousness. Instead, they may manifest with other perceptual or cognitive or autonomic or motor alterations or even what to the patient may be indescribable types of experiences. In psychiatric presentations, they may manifest as subtle episodic behavioral, affective or cognitive changes which most commonly derive from the temporal lobe: hence the term Temporal Lobe Epilepsy - an anatomical origin term replaced today by the functional and broader non-anatomical description of "complex partial seizures". The most classical and common epileptic seizures are of the "grand mal" or generalized "tonic - clonic" kind. These usually involve relatively short ( 10-30 seconds ) tonic movements with marked extension / flexion of muscles but no shaking and then a longer (15-60 sec) clonic tonic manifesting as rhythmic muscle group shaking. These movements may be associated with a phase of laryngeal stridor due to tonic muscles manifesting as a high pitched scream sound. Urinary and occasionally fecal incontinence may occur due to sphincteric change and the seizures are almost invariably followed by headache, sleepiness and / or confusion. When preceded by perceptual, autonomic, affective or cognitive alterations such seizures are partial seizures secondarily generalized. These partial seizures are classified as complex partial when any impairment of consciousness occurs, and as simple partial when there are focal features but no change in consciousness. Often this call is difficult to make. An epileptic patient who experiences special symptoms lasting seconds referable to the cerebral cortex or limbic system such as a buzz in his ear, burning rubber smells, distortions in size, sudden sweating, or uncontrolled weeping, sudden right arm jerks, or a rising epigastric sensation may be having simple partial seizures. However, if the patient experiences with these symptoms, a strange sense of depersonalization or of unreality, or a sudden profound mood change over seconds, or a disorientation sense or loss of time or a frank absence of consciousness with no other manifestation, he may in fact be having subtle alterations of consciousness and the symptoms would reflect complex partial seizures.

    Some seizures do not have a specific locus of origin of firing to produce focal features and only have the tonic clonic movements or transient impairments of consciousness without movements (e.g. petit mal absences which are diagnosable on EEG) or variants of these (e.g. bilateral myoclonus, tonic or atonic episodes) are classified as generalized from the start and therefore called generalized epilepsy. (The terminology has changed: Previously primary generalized epilepsy referred to seizures generalized from the start in the presence of normal brain function and electroencephalographic (EEG) background; secondary generalized epilepsy was also generalized from the start but had abnormal brain function and background as in mental retardation with epilepsy. We should distinguish secondary from secondarily generalized.)

    Neuropsychiatrists, in fact, frequently recognize that marked behavior disturbance may correlate with paroxysmal discharges in the brain (particularly the temporolimbic areas) on the electroencephalogram although these patients would not be considered to have a seizure disorder by many neurologists. Many neuropsychiatrists believe these patients represent a form of episodic electrical cerebral firing which Dieter Blumer and I for non-prejudicial reasons have called "Paroxysmal Neurobehavioral Disorder". We characterize the individual events as "atypical spells".
    Thus the spectrum of epilepsy and psychiatry is broader now than it was, and a whole area - possibly the majority of patients presenting to psychiatrists - is couched in controversy and in diagnostic labels that are ambiguous, uncertain, non-existent or invented post-hoc based on pragmatic experience.

    Sometimes episodes may well be seizure phenomena, although they cannot be proven to be so on EEG. This is particularly important when such symptoms as major episodes of mood lability lasting seconds happen or confusional episodes occur or when a symptom like an unexplained rising epigastric sensation occurs on its own. These can be classified as atypical spells under paroxysmal neurobehavioral disorder (PND) because the actual phenomena may not have been proven to be seizures. Many of these patients respond to anticonvulsant treatment so that appropriate neuropharmacologic response is an important diagnostic indicator.

    Both proven seizure phenomena and PND may be sequelae after an acute brain insult such as closed head injury, vascular episode, encephalitis, anoxia or tumor but these conditions may also be mobilized by chronic cerebral exposure to recreational drugs of abuse like cocaine, LSD, cannabis and amphetamines. Some epileptics have loaded family histories of seizures or other episodic events like subjective paranormal experiences but for the most part the etiology of the epilepsy is not easily determined - cryptogenic.

    TABLE 1

    International League Against Epilepsy Revised Classification of Epileptic Seizures (1981)

    1. Partial (focal, local) seizures:
      1. Simple - motor, somatosensory, autonomic, psychic
      2. Complex
        1. Impaired consciousness at outset
        2. Simple partial followed by impaired consciousness
      3. Partial seizures evolving to generalized tonic-clonic (GTC)
        1. Simple to GTC
        2. Complex to GTC
    2. Generalized seizures (convulsive or non-convulsive)
        1. Absence seizures
        2. Atypical absences
      1. Myoclonic
      2. Clonic
      3. Tonic
      4. Tonic-clonic
      5. Atonic
      6. Combinations
    3. Unclassified epileptic seizures

    Epilepsy plus and Epilepsy standard

    Most epileptics are healthy. They do not have any psychiatric stigmata, and the only difference between them and a general non-epileptic population is the occurrence of seizures. I have dichotomized epileptics:

    1. Possibly 90% of cryptogenic epileptics constitute the epilepsy standard patient: These epileptic patients have no more psychopathology than the average patient. The epilepsy standard patients, without additional psychopathology, are functional within the community, and should be differentiated from the epilepsy plus patients.

    2. The second group is the epilepsy plus patient. This minority of epilepsy patients have significant behavioral or psychiatric abnormalities relating to the organic aspects of their seizure disorder. These patients frequently present psychiatrically, or may be evaluated commonly in an academic setting. They may have been misdiagnosed or be more resistant to conventional anticonvulsants alone needing psychotropics as well. As many as one-half require hospitalization for this. These patients may have a broader coarse neurobehavioral syndrome and may be mentally retarded (one subpopulation therefore has "secondary generalized epilepsy"). They also include a group in which psychoses and seizures coexist (at a frequency 3 to 5 times the general population incidence). Finally, probably the most common population with severe psychopathology is Blumer's interictal dysphoric disorder patients. These patients require anticonvulsant plus antidepressant treatment.

    These conditions remain controversial, and particularly so the debate as to whether these are linked with temporal lobe foci or relate to seizure disorders in general. The incidence with temporal lobe foci is certainly higher, but a number of confounding variables, such as dosage, number of anticonvulsants prescribed, severity of seizures, impairments in seizure control and number of seizure types, may play significant roles.

    The epilepsy plus patient probably constitutes a very small minority of the total number of epileptic patients that will generally present to major centers, and may be intractable, difficult to manage, and have behavioral disorders or associated coarse neurobehavioral syndromes. These are superimposed on, or coexist with the epilepsy, and their behavioral disturbances, or psychoses, may or may not be causally related to their epilepsy. Moreover, the differentiation should be clinical as well as academic, because interpretations of psychiatric populations with epilepsy as having causal links and not just coexistent conditions, may distort further research.

    One other factor distorts interpretations of patients with epilepsy and psychopathology. Psychiatric patients are sometimes perceived as having epilepsy, when in fact they do not. Their previous labels of epilepsy may relate to a single seizure, often associated with alcohol or withdrawal or other medical conditions. Alternatively, they may have had an acting-out episode, incorrectly interpreted as a seizure. They may be on anticonvulsant medication for mood disorder or paroxysmal episodic behavior disturbance, and the medication may be misconstrued by a new treating physician as for seizure control. They may be wrongly on anticonvulsant medication for black-outs which have not been proven to be epileptic. Finally, an abnormal EEG does not make the patient epileptic. It is probably best to limit epileptic psychiatric patients to those having a confirmed history of epilepsy associated with at least two documented seizures which were not linked to withdrawal phenomena or pyrexia or other acute events. Conversely, patients who are epileptic may have periods of altered or impaired consciousness following on their seizure, with the resulting confusion producing behavioral disturbances. This should not be interpreted as psychiatric; it is clearly a post-ictal confusional state. Similarly, patients diagnosed with pseudoseizure phenomena may be having real seizures which have been misdiagnosed or in addition to their non-epileptic events.

    Possible temporal lobe symptoms

    Seizure disorders with behavioral disturbance, may initially be interpreted as psychiatric in origin. Many such problems relate to the temporal lobe of the brain. The features of temporal lobe epilepsy and non-epileptic dysfunction of the temporal lobe are so varied and so protean that it is necessary to classify them. I have suggested the term "Possible temporal lobe symptoms" (PTLSs) relate to features which can be induced by stimulating areas of the temporal lobe during neurosurgery. These symptoms only become specific symptoms of temporal lobe dysfunction if their occurrence is validated empirically during a seizure - either through observation or by the electroencephalogram (hence the word "possible" in possible temporal lobe seizures). Great care must be taken in interpretation of such features : For example, using a phenomenological analysis, I demonstrated that the symptom of deja vu commonly regarded as symptomatic of temporal lobe epilepsy indeed had a very special phenomenologic quality in patients with temporal lobe epilepsy. Like many other such focal symptoms, this involves its association with post-ictal features such as sleepiness, headache and clouded consciousness and its link in time with these features. This association provides an excellent clue to the existence of temporal lobe epilepsy. However, deja vu is a normal phenomenon occurring in 70 percent of the population and unless such phenomenological detail is obtained, patients' symptomatology may be misinterpreted. I similarly studied olfactory hallucinations but a specific type of temporal lobe epilepsy olfactory hallucination could not be demonstrated although there were suggestive features. A major message, therefore, may be the relevance of adequately assessing the symptomatology of patients presenting with epilepsy. It may be that this is a direction as relevant as electroencephalographic monitoring. Most of all it reminds us how slender our interpretations of other related but different symptoms such as "he experiences strange smells" might be and the fact that it is critical to elicit whether these are episodic in quality and linked with other symptomatology particularly epileptic or temporal lobe. A written test instrument designed to screen for such symptoms which I use in clinical practice is the INSET - The INVENTORY OF NEPPE OF SYMPTOMS OF EPILEPSY AND THE TEMPORAL LOBE (INSET). The INSET involves screening for possible temporal lobe, epileptic and organic symptoms and spells. Thereafter the symptoms are categorized into several headers namely nonspecific symptoms, possible and controversial temporal lobe symptoms, seizure related and other focal features. The test is based on the subject and / or his family responding to questions which are thereafter elaborated in greater clinical detail. Responses are at two time levels: current as well as the most common frequency in the remote past and require the patient to rank frequency from never through less than yearly to more than daily (i.e. 0-6). Questions in the INSET have been based on the earlier Neppe Temporal Lobe Questionnaire which itself derived from an intensive literature review on the topic. The INSET plus medical history is a major determining factor for whether to order follow-up specialized electroencephalograms such as ambulatory EEG.

    TABLE 2: POSSIBLE TEMPORAL LOBE SYMPTOMS (PTLSs)

    Controversial PTLSs (CPTLSs)

    1. severe hypergraphia
    2. severe hyperreligiosity
    3. polymodal hallucinatory experience Paroxysmal (Recurrent) Episodes of:
    4. profound mood changes within hours
    5. frequent subjective paranormal experiences e.g. telepathy, mediumistic trance, writing automatisms, visualization of presences or of lights/colors round people, dream ESP, out-of body experiences, alleged healing abilities
    6. intense libidinal change
    7. Uncontrolled, lowly precipitated, directed, non-amnesic aggressive episodes;
    8. recurrent nightmares of stereotyped kind
    9. episodes of blurred vision or diplopia

    Not Necessarily Disintegrative PTLSs (NPTLSs)

    Symptoms Not Necessarily Requiring Treatment Paroxysmal (Recurrent) Episodes of:

    1. Complex visual hallucinations linked to other qualities of perception such as voices, emotions, or time

      Any form of:

    1. Auditory perceptual abnormality;
    2. Olfactory hallucinations;
    3. Gustatory hallucinations;
    4. Rotation or disequilibrium feelings linked to other perceptual qualities;
    5. Unexplained "sinking," "rising," or "gripping" epigastric sensations;
    6. Flashbacks;
    7. Illusions of distance, size (micropsia, macroscopy), (micropsia), loudness, tempo, strangeness, unreality, fear, sorrow;
    8. Hallucinations of indescribable modality.
    9. Temporal lobe epileptic deja vu (has associated ictal or postictal features {headache, sleepiness ,confusion} linked to the experience in clear or altered consciousness )
    10. Any CPTLSs which appear to improve after administration of an anticonvulsant agent such as carbamazepine.

    Disintegrative PTLSs (DPTLSs)

    Symptoms Requiring Treatment: Paroxysmal (Recurrent) Episodes of:

    1. Epileptic amnesia;
    2. Lapses in consciousness;
    3. Conscious "confusion" ("clear" consciousness but abnormal orientation, attention and behavior);
    4. Epileptic automatisms;
    5. Masticatory-salivatory episodes;
    6. Speech automatisms;
    7. "Fear which comes of itself" linked to other disorders (hallucinatory or unusual autonomic) ;
    8. Uncontrolled, unprecipitated, undirected, amnesic aggressive episodes;
    9. Superior quadrantic homonymous hemianopia;
    10. Receptive (Wernicke's) aphasia.
    11. Any CPTLSs or NPTLSs with ictal EEG correlates.

    Seizure related features ( SZs )

    Any typical absence, tonic or clonic or tonic-clonic or bilateral myoclonic seizures in the absence of metabolic, intoxication or withdrawal related phenomena.

    Clearly there is a greater need to pay attention to unusual episodic symptoms. This will ultimately lead to a workable classification and the recognition that certain seizure like features need be treated by psychiatrists.

 

 


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