Temporal lobe epilepsy (TLE), now more commonly called complex
partial seizure disorder so as to include seizures that originate
in the frontal foci, straddles the borderland between psychiatry
and neurology. Since the condition may involve gross disorders
of thought and emotion, patients with temporal lobe epilepsy frequently
come to the attention of psychiatrists. But since symptoms may
occur in the absence of generalized grand mal seizures, physicians
may often fail to recognize the epileptic origin of the disorder.
Indeed, misdiagnosis and failures of diagnosis are common in TLE.
Fortunately, the illness is marked by certain "signature"
symptoms that can aid in its identification.
John Hughlings Jackson observed in the late 1800s that seizures
originating in the medial temporal lobe often result in a "dreamy
state" involving vivid memory-like hallucinations sometimes
accompanied by déjà vu or jamais vu (interpreting
frequently encountered people, places or events as unfamiliar).
Jackson wrote of "highly elaborated mental states, sometimes
called intellectual aura," involving "dreams mixing
up with present thoughts," a "double consciousness"
and a "feeling of being somewhere else." While the "dreamy
state" can occur in isolation, it is often accompanied by
fear and a peculiar form of abdominal discomfort associated with
loss of contact with surroundings, and automatisms involving the
mouth and GI tract (licking, lip-smacking, grunting and other
sounds).
Experiential Illusions
In the 1940s and '50s, Wilder Penfield, a neurosurgeon at the
Montreal Neurological Institute, artificially elicited "dreamy
states" by cortically stimulating the lateral temporal neocortex,
the anterior hippocampus or the amygdala in awake epileptic patients
prior to their surgical resections. During these operating room
experiments, the patients experienced what Penfield referred to
as "experiential illusions."
These illusions involved an alteration, sometimes subtle, of the
person's relationship to his or her environment, as well as emotional
response to it. In contrast to psychotic persons, Penfield's patients
remained fully aware that their altered interpretation was an
illusion. A friend's voice may sound remote, or a well-known living
room may appear unfamiliar, but the meaning is preserved, the
voice does not become depersonalized, nor does the living room
lose its identity. Even those patients describing feelings of
unreality state that they know at the same time what reality is,
observed Penfield. This is an important distinction from schizophrenia
and other psychotic states.
For example, a patient of mine with temporal lobe epilepsy often
feels compelled to stare for brief moments at a coffee table in
her living room since, as she put it, "It just doesn't look
exactly like my coffee table." After a few seconds, the feeling
disappears. At no time does she think that the table has actually
changed; the only thing that varies is her perception and "interpretation"
of it.
Altogether Penfield (Mullan and Penfield 1959) divided the illusions
of interpretation into four groups:
Auditory illusions accompanied by the perception that sounds
were louder or clearer, fainter or more distinct, nearer or farther
away;
Visual illusions where things seemed clearer or blurred,
nearer or farther away, larger or smaller; fatter or thinner;
Illusions of recognition where present experience seemed
familiar, strange, altered or unreal; and
Illusions of emotion consisting of feelings of fear, loneliness,
sorrow or disgust.
None of these groups of symptoms are unique to epilepsy. Migraine
sufferers regularly experience illusions of sound, sight, taste
and smell.
True hallucinations-those without external stimulus-may occur
in complex partial seizures, especially the classic olfactory
or gustatory hallucination seen with uncinate fits.
In a psychiatric or neuropsychiatric practice, the most commonly
encountered illusions of interpretation are those of emotion.
Typically, these are sudden in onset and unrelated to conscious
experiences or anything in the environment:
A 40-year-old patient with a 20-year history of mental illness
had been diagnosed at various times as having either schizophrenia
or borderline personality disorder. She regularly experienced
sudden episodes of dread that occurred without warning and without
relationship to any inner experiences or anything happening around
her.
On one occasion while waiting for a cab to come to her home to
take her and her husband to an event they had both been looking
forward to attending, she experienced such an overwhelming sense
of dread she sank to the floor with a compulsion to hurt herself.
Because of the strong visceral component to her symptoms and the
inexplicable sudden change in mood, a neurological workup was
ordered. An electroencephalogram (EEG) "showed the presence
of an intermittent epileptiform disturbance confined to the right
anterior and mid-temporal regions. EEG findings would be compatible
with partial complex seizure disorder." On carbamazepine
(Tegretol), she has been free of the seizures for 10 years.
In most instances, the emotion experienced as part of the seizure
is a disturbing one variously described as dread or a feeling
of impending doom; in others, the emotion may be experienced as
pleasant or euphoric, as Dostoyevsky described. Since the feelings
can arise de novo without any identifiable precipitant, an incorrect
diagnosis of an acute panic attack may be entertained. Almost
always, however, the patient will describe additional experiences
that will help in the differential diagnosis. Included here is
a strong visceral component to the symptoms: a feeling or sensation,
almost always unpleasant, traveling upward from stomach to head.
In an attempt to explain the experience, the patient will sweep
his or her hands upward starting at the abdomen. Descriptions
such as "a wave," "something flowing upward"
are often employed.
Often such details must be elicited by careful, tactful questioning,
because the patient will be reluctant to describe the experience;
its intensity and bizarre nature arouses fears of insanity. The
physician frequently can sidestep this reaction by asking: "Have
your episodes ever involved anything strange?" with a lack
of emphasis on the word strange, thereby suggesting that
strange experiences are not at all unusual with these kinds of
seizures. Another approach is to say: "On occasion persons
who have experienced some of the things you have told me about
have described other experiences they have been reluctant to discuss
because they were afraid other people, even their doctors, might
think them crazy." Questions about specific epileptic experiences
should be delayed until the end of the interview to avoid suggestibility.
TLE Personality?
Controversy continues as to the validity of a so-called temporal
lobe personality. Certainly, many of the patients tend to be obsessive
and over-inclusive in their thinking, often satisfying some or
all of the requirements for obsessive-compulsive personality:
hyperphogia may be seen in some patients. Their speech and thinking
is "viscous" and ponderous with a tendency toward loquacity
and the insistence on the elaboration of fine and often tedious
distinctions. Outbursts of irritability, rather than frank violence,
are hallmarks of TLE.
When interviewing suspected TLE patients, it's important to inquire
about their birth and any complications of the pregnancy. Forceps
deliveries, now almost unheard of, were quite common years ago
and led to compressive injuries of the brain, anoxic damage to
Ammon's horn in the hippocampus and the subsequent temporal lobe
epilepsy. Also ask about generalized seizures, head injuries,
concussions, temper tantrums and, with males, a history of aggression,
fire setting, truancy and impulsive behaviors. Has the patient
experienced frequent déjà vu, jamais vu, depersonalization,
autoscopy or sudden mood swings accompanied by visceral or oral
sensations? Do others complain that the patient often doesn't
seem to be listening, appears to be daydreaming or otherwise preoccupied?
Often the patients are aware of their lapses, and almost all of
them experience some form of memory disturbance, even if nothing
more than a vague inability to grasp things with sufficient precision.
Other rare presentations include anorexia nervosa (Signer and
Benson 1990), multiple personality (Schenk and Bear 1981) or compulsive
water drinking (Remillard, et al. 1981). Spitting and embarrassment
have been described as the aura of a complex partial seizure (Devinsky
and colleagues 1982; Hecker and colleagues 1972).
Finally, the clinician should inquire as to a family history of
migraine, since migraine is overrepresented in families with TLE
and can mimic the majority of TLE symptoms.
Tactful inquiry may result in anecdotal reports of sexual disturbances
in some patients with TLE. Most common is a global hyposexuality
affecting both libidinal and genital arousal. In individual instances,
such patients may be mistakenly diagnosed as exhibiting hypoactive
sexual desire disorder. These two can be distinguished by eliciting
on history other hallmarks of temporal lobe epilepsy. Although
rarer than hyposexuality, a great variety of other sexual disorders
may be encountered in TLE. These include fetishism, transvestic
fetishism, sadomasochism, pedophilia, frotteurism and voyeurism.
During the seizures, the patients may also experience genital
sensations, even feelings of sexual excitement evoked by the epileptic
discharges.
Episodes of frank psychosis can be the initial presentation of
TLE: a 38-year-old businessman with a history of childhood staring
spells and petit mal epilepsy confirmed by EEG, came under considerable
work pressure and began an around-the-clock work marathon lasting
two days. Suddenly, early in the morning of his second "all-nighter,"
he experienced a "realization" that his difficulties
must be conveyed to the president of the United States. After
his arrest at the White House and transfer to the psychiatric
ward of a local teaching hospital, an EEG was ordered for him
because clinicians uncovered a history of childhood epilepsy.
It showed bursts of generalized spike/wave discharges consistent
with a generalized seizure disorder.
A magnetic resonance imaging (MRI) scan showed "two foci
of increased signal noted in the medial aspect of the right temporal
horn associated with a widening of the right temporal horn."
A neurology consult suggested the use of anticonvulsants only
if the patient became "symptomatic." The psychiatrist
concluded: "Since the patient had no observable physical
symptoms of seizures, we would withhold the anticonvulsant at
this time." On low doses of antipsychotics the patient improved,
another tip-off that his psychosis was atypical in etiology. (Clinicians
should note, however, that antipsychotics tend to lower the seizure
threshold, thereby increasing patient's incidence of seizure.)
At discharge he left the hospital uncertain and worried about
what had happened to him. When I saw him in initial consultation
several months later, the psychosis had cleared and he was no
longer on any medications. Nonetheless, he continued to experience
difficulties with memory and "getting my thinking exactly
right." Neuropsychological testing showed "deficits
consistent with the local or remote effects of a right temporal
lesion." When placed on carbamazepine, the patient reported
improvement in thinking and memory.
In retrospect, the most likely explanation was this: The lack
of sleep and food coupled with stress led to the onset of a schizophreniform
episode in a person with a latent seizure disorder. Because the
episode was not associated with any signs of generalized epilepsy,
it was not recognized as an example of complex partial seizure
disorder by either psychiatrist or neurologist . After the psychosis
had cleared, the patient was still left with a problem involving
memory and focus originating from the hippocampus, a secondary
effect of the abnormality in the right temporal region. The memory
disturbance improved with anticonvulsant administration.
TLE also may be responsible for chronic rather than just acute
psychoses. While any of the symptoms of schizophrenia may be encountered,
paranoid traits are the most common. TLE patients can be distinguished
from schizophrenic patients by the maintenance, when not acutely
ill, of warm affect and good rapport. In addition to the history,
the diagnosis of complex partial seizure disorder can be aided
by EEG. However, since such diagnosis remains a clinical one,
it should be noted that several negative EEGs do not rule out
the diagnosis of TLE in a given patient. Other diagnostic aids
include MRI, single photon emission computed tomography (SPECT)
and positron emission tomography (PET). Interictal SPECT of cerebral
blood flow is not nearly as helpful as ictal SPECT. Even more
sensitive, although not generally available, is PET imaging of
interictal cerebral metabolism. PET permits greater spatial resolution
and versatility. Only MRI can image the structural changes associated
with the underlying epileptic process. Quantitative evidence of
hippocampal volume loss is correlated with seizure onset in medial
temporal structures.
The treatment of TLE is complicated by the fact that many times
improved seizure control via anticonvulsants leads to deterioration
of the neuropsychiatric status. Schizophrenia-like epileptic psychoses
often emerge when anticonvulsants are normalizing or improving
the seizure activity. If this antithesis isn't recognized, the
psychosis will soon become more of a problem than the seizures.
One expert, Dietrich Blumer, M.D., has gone so far as to claim:
"It is probable that the modern schizophrenia-like epileptic
psychoses are largely iatrogenic in nature, caused by modern ability
to control seizures."
TLE management presents a conundrum. While the illness is an epileptic
one and treated by neurologists, many neurologists remain unfamiliar
with and even uninterested in its neuropsychiatric components.
But by ignoring the experiential symptoms, the neurologist deprives
the patient of the opportunity to coherently integrate all aspects
of the epilepsy. It may also cement the patient's misconception
that in addition to the epilepsy, he or she suffers from a "mental
illness."
Total management of TLE by a psychiatrist is also not without
problems. Although temporal lobe epileptic patients are particularly
intriguing to psychiatrists because of the nature of the symptoms,
these "psychic" seizures can generalize at any time
into psychomotor status or grand mal attacks. What's more, neither
the timing nor the seriousness of grand mal episodes can be predicted;
the initial generalized seizure sometimes occurs many years after
the first manifestations of the illness and may culminate in status
epilepticus and death.
For these reasons, a physician should undertake the treatment
of TLE patients only if he or she has sufficient training and
experience in the overall management of epilepsy. When this isn't
the case, close collaboration between psychiatrist and neurologist
offers the best venue for successful management of this fascinating
"bridge" between neurology and psychiatry.
