Behavioral aspects of frontal lobe epilepsy
Behavioral Aspects of Frontal Lobe Epilepsy
University Clinic of Epileptology Bonn, Sigmund Freud Strasse 25,
D-53105 Bonn, Germany
Received February 24, 2001; accepted for publication August 15, 2001
There is growing interest in disorders of behavior, personality, and mood associated with focal
epilepsies, though the neuropsychological and behavioral or psychiatric aspects of epilepsy have
usually been treated separately. The causes of behavioral disorders in patients with focal epilepsies
are multifactorial, though the positive effects of seizure control on behavior suggest that state
dependency is a major contributing factor. Patients with temporal lobe epilepsy manifest depression,
anxiety, neuroticism, and social limitations, as well as impaired memory. By contrast, studies of
cognitive function in patients with frontal lobe epilepsy show executive dysfunctions in response
selection/initiation and inhibition, as well as cognitive impairment, hyperactivity, conscientiousness,
obsession, and addictive behaviors. © 2001 Academic Press
Key Words: frontal lobe epilepsy; cognition; seizure semiology; behavior; personality; quality of life.
To date, neurobiologists interested in behavior and
epilepsy have focused primarily on temporal lobe epilepsy
(TLE) and mesial temporal lobe epilepsy (mTLE),
in particular, mostly because TLE accounts for the majority
of patients with focal epilepsies seen at epilepsy
referral centers. For example, in the Bonn series of patients
with pharmacoresistant epilepsies, approximately
80% had TLE. Another reason is that patients with mTLE
often constitute a well-defined cohort with respect to
underlying pathology (hippocampal sclerosis), a frequent
history of febrile convulsions, an early onset of
epilepsy, and memory problems as the prominent neuropsychological
impairment. Further, the affected cerebral
structures and epileptogenic regions associated with
TLE are usually circumscribed, and the structural pathology
can be readily characterized by quantitative MRI
(T2 relaxometry and volumetry) or histopathological examinations
of resected specimens.
Thus, frequency of occurrence, homogeneity of phenotypic
expression, and well circumscribed and quantifiable
pathology provide ideal prerequisites for the study
of the functional and behavioral correlates of TLE. Ac-
1 To whom correspondence should be addressed. Fax: 1 49 (0)
228 287 6294. E-mail: C.Helmstaedter@uni-bonn.de.
great progress has been made in recent years
with respect to the neuropsychological and cognitive
aspects of TLE. Additionally, studies have led to a rediscovery
of the role of the temporal lobes in emotion and
The conditions for studying frontal lobe epilepsy
(FLE) are quite different. FLE, despite the size of the
frontal lobes, is less frequent than TLE. In our own
series, patients with FLE represent about 15% of the
patients with pharmacoresistant epilepsies. Further,
the site and type of the underlying pathology are very
heterogeneous. Finally, ictal and interictal clinicoelectric
manifestations of FLE are infrequently localizable
because multiple connections to most other brain areas
enable fast and widely distributed propagation of
epileptic activity. The functional correlates of frontal
pathology in epilepsy are thus less well understood.
FRONTAL LOBE: ANATOMY, FUNCTION,
AND ASSOCIATED BEHAVIOR
Based on its cytoarchitectonic structure, the frontal
lobe is traditionally divided into two parts, each with
Copyright © 2001 by Academic Press
All rights of reproduction in any form reserved.
|Behavioral Aspects of Frontal Lobe Epilepsy
important functional characteristics. The posterior
part controls motor movement and is subdivided into
a premotor area and a motor area, which control preparation
for movement and actual execution of movement,
respectively. The anterior part, the prefrontal
cortex, is especially important for higher mental functions,
such as anticipation and planning, initiative,
judgment, and in the control of mood, will power, and
the determination of personality (1, 2). The prefrontal
cortex can be further subdivided into the dorsolateral
cortex and the orbitofrontal cortex, though this is simplistic
because the orbitofrontal cortex is a heterogeneous
area connected with a wide range of other prefrontal,
limbic, premotor, sensory areas in addition to
subcortical nuclei (3).
Damage of the dorsolateral prefrontal cortex is typically
associated with impairment of executive functions
and working memory, whereas damage of the
orbitofrontal cortex leads to impairment of the choice
of behavior, the establishment of emotional valences,
and the evaluation and balancing of the past and
future consequences of a given behavior (4–6). Studies
in common marmosets suggest a dissociation between
the lateral and the orbital medial divisions of the
prefrontal cortex according to which the former selects
and controls actions on the basis of higher-order rules
and the latter controls different behavior on the basis
of lower-order rules (7). The significance of the orbitofrontal
cortex for social and interpersonal behavior in
humans was again demonstrated by the recent report
of two patients, one with a traumatic brain injury at 15
months of age and the other with a frontal tumor
resected at 16 months of age, who both showed severe
impairment of social and moral behavior (8).
Traditionally, behavioral dyscontrol in epilepsy has
been attributed to dysfunction of temporolimbic structures.
Evidence for the involvement of the amygdala
in aggression comes from human and animal stimulation
studies, from the effects of antiepileptic drugs
on activating and inhibiting aggression, and, recently,
from direct correlations of amygdala volumes with
aggression in patients with mesial epilepsy (9 –12).
Aggression associated with involvement of the amygdala
appears to be defensive rather than offensive in
Disinhibition phenomena or a loss of impulse control
as observed in patients with frontal lesions suggests
the importance of frontal regions in the genesis
of impulsive aggressive behavior. The orbitofrontal
cortex, as the border zone between the frontal lobe and
the limbic system, links the frontal and limbic components
involved in disorders of behavioral control. The
anterior cingulate gyrus, which is also strongly connected
to the amygdala, has also been associated with
deviant social behavior and pathological affective
states when damaged (14).
Attributing antisocial and aggressive behavior to
frontal lobe damage is not new. A prominent and
often-cited example is the historic case of Phineas
Gage, who after an accident with a severe frontal brain
injury changed from a well-behaved man into an irresponsible
and convention-neglecting person (15, 16).
One new concept, brought out by the case reports of
Anderson et al. (8), is that patients with frontal lobe
damage not only may display severe behavioral disorders
but also may neglect the moral aspects of their
behavior, depending on the age at which the damage
occurred (17). Consequently, the orbitofrontal cortex
seems important both for behavior control and for the
acquisition of social and interpersonal rules of conduct.
It is important to note that irresponsible, aggressive,
and sociopathic behaviors can occur irrespective
of intellectual abilities, which are often well preserved
in frontal lesions.
The orbitofrontal cortex and medial prefrontal cortex
are believed to play a central role in addictive
behavior, attention deficit– hyperactivity disorder, and
negative emotion and major depression, respectively
(18 –21). Davidson and co-workers further propose a
key role of the prefrontal cortex in the regulation of
emotion in violent subjects and those predisposed to
Damasio proposed the “somatic marker” hypothesis
as a theoretical basis for the role of the prefrontal
cortex in the interplay of cognition and emotion (23).
This hypothesis posits that responses to external stimuli
do not rely on either conditioning processes or
cognition alone, but on somatic “marker signals” or
autonomic response sets, which determine the conscious/
unconscious connection between stimulus
conditions, feelings, and behavior.
EPILEPSY AND ASSOCIATED
Case reports of behavioral and personality disorders
in patients with severe brain lesions raise the
question of whether there might be parallels in the
behavior of patients with seizures arising from the
same brain regions. With the exception of rare cases of
ictal aggression, postictal confusional states, or psychosis
(24), behavior and personality disorders observed
in patients with frontal lobe epilepsy appear to
Factors Affecting Cognitive and Mood States in Epilepsy
|States of epilepsy
||Interictal (seizure free after successful
||Nonconvulsive status epilepticus
||Local versus distant effects
||For example, alien tissues versus
migration and developmental disorders
(confounded with different ages at
||Extent, location, lateralization
||Positive versus negative psychotrophic
be less dramatic than found in the published case
reports. Furthermore, as with TLE, one can hardly
expect to find the prototypical “frontal epileptic personality”
or “Wesensa¨nderung,” respectively. Personality
is by definition more trait than state dependent.
In patients with epilepsy, it is particularly difficult to
determine whether a given behavior has trait characteristics
or not. Concluding that abnormal behaviors
have persisted requires follow-up observations over
long time intervals, which generally are not reported
in the literature. Several epilepsy-related variables can
account for reversible changes in cognitive abilities
and mood states (see Table 1). Finally, despite the long
history of patients becoming seizure free from epilepsy
surgery, it is still not clear whether seizures are
necessary for the development of epilepsy-related behavior
and mood disorders. Behavior in patients with
epilepsy should be defined by state as it relates temporally
to seizure events, e.g., ictal, postictal, or interictal.
Recent findings with regard to seizure prediction
by nonlinear measures of complexity loss as recorded
by intracranial EEG suggest that the preictal period
should also be considered (25). Accordingly, patients
may report a prodrome consisting of increased dysphoric
mood and cognitive problems well before their
seizures begin. Finally, the observation of behavior
problems following successful treatment with epilepsy
surgery or antiepileptic drugs implies that an
additional state that should be evaluated is that of
seizure freedom associated with treatment.
Epileptic activity can affect brain areas distant from
the epileptogenic zone, causing cognitive and behavior
problems (26). Notwithstanding seizures and interictal
epileptic activity one must also differentiate
the underlying pathology(ies) and when they occurred
(which could influence effects on brain maturation
and the development of cognition and personality).
We must also consider the effects of chronic
antiepileptic medications, which may have positive or
negative psychotropic side effects (27). Antiepileptic
drugs can have different effects in patients with lesional
epilepsy compared with nonlesional patients,
and they may act differently dependent on seizure
control (28). Thus, the effects of underlying pathology,
seizures, and pharmacological treatment must be considered
individually and as they may interact in a
FRONTAL LOBE EPILEPSY:
NEUROPSYCHOLOGY AND EVIDENCE
OF SPECIFIC BEHAVIORAL DISORDERS
The development of neuropsychology in frontal
lobe epilepsy is probably best reflected by Brenda
Milner’s description of her evaluation of Penfield’s
patient K.M., the frontal counterpart of the temporal
patient H.M. This patient had a penetrating head injury
in 1928, developed seizures, and underwent surgery
of the anterior parts of both frontal lobes. Surgery
successfully controlled the seizures and led to improved
behavior as well as improved IQ. However,
when reevaluated with the newly developed Wisconsin
Card Sorting test in 1962 he showed severe impairment
in flexible categorical thinking and concept formation
while the IQ still was average (see Milner (29)).
This case exemplifies how much outcome interpretation
depends on test sensitivity and test selection.
Since that time surprisingly few attempts have been
made to comprehend the cognitive characteristics of
patients with frontal lobe epilepsy in group studies
(26). Unfortunately, most data from Milner’s era stem
from operated patients and thus tell us more about
frontal lobe lesions than about frontal lobe epilepsy.
Furthermore, most earlier studies focused on single
functions more or less following a rather monistic
view of a frontal “central executive” (30). Major impairments
indicated by these studies are problems in
concept formation, response inhibition (31), estimations
(32), conditional associative learning (33, 34), and
profit from information provided in advance in choice
reaction tasks (35). Focusing on memory Delaney et al.
|Behavioral Aspects of Frontal Lobe Epilepsy
found no differences in measures of memory when
nonoperated patients with unilateral frontal lobe foci
were compared with healthy controls (36). The first of
our own studies found that deficits in attention are the
most significant problem in patients with frontal lobe
Later systematic group studies in nonresected patients
with FLE followed the theoretical suggestion of
different frontal subfunctions (38) and met the requirements
of the manifold frontal lobe pathology by
the use of a broader range of tests. These addressed
different aspects of attention, motor coordination, psychomotor
speed, fluency, response inhibition, conceptual
formation and shift, as well as planning, guessing,
Between 1996 and 1999 Upton and co-workers published
a series of five articles reporting different findings
on neuropsychology in the their sample of 74
subjects with frontal lobe epilepsy (39–43). Using a
test battery with different measures of executive functions
and motor skills they came to the conclusion
patients with frontal lobe epilepsy show a deficit pattern
similar to that found in frontal lobe dysfunction in
general (39). As compared with patients with temporal
lobe epilepsy, frontal patients show poorer motor
cordination, guessing, estimation, and response inhibition.
Similarly, we found in 23 patients with frontal
lobe epilepsy that cognitive problems could be diagnosed
with a broad range of 10 “frontal” tasks with
about double as many test parameters. The great number
of test parameters, however, turned out to be
highly redundant and could be statistically reduced to
four relatively independent functional areas: “psychomotor
speed/attention,” “motor coordination,”
“working memory,” and “response inhibition.” These
four factors explained 70% of the total variance. When
compared with patients with temporal lobe epilepsy,
those with frontal lobe epilepsy were characterized by
prominent impairment in motor skills and response
inhibition (44). Problems in speed/attention and
working memory were frequent but they appeared
rather nonspecific since they were also observed in the
temporal lobe group. This, however, does not necessarily
contradict the assumption that these are frontal
functions. An imaging study by Jokeit et al. showed in
this respect that in patients with temporal lobe epilepsy,
prefrontal metabolic asymmetries are evident
that are associated with “frontal lobe measures” and
In another of our own studies we addressed the
cognitive consequences of frontal lobe surgery. We
evaluated 33 patients pre- and postoperatively. First,
we were able to confirm the impairment pattern of
impaired motor skills and response inhibition. Second,
we showed that frontal surgery does not cause considerable
additional damage as far as eloquent cortex
(SMA, motor and language area) is spared. However,
when surgery included resection of the SMA the most
prominent neuropsychological symptom besides neurological
deficits directly after surgery was a SMA
deficiency syndrome (impairment of initiation) with
aphasia (speech arrest and transcortical aphasia) (46).
Additional psychomotor slowing was observed in lobectomies
as compared with lesionectomies.
Looking closer at clinical variables that might explain
the impairment pattern in nonresected patients,
no consistent picture emerges. According to Upton
and Thompson seizure frequency and the duration of
epilepsy have an effect on performance but this appears
to be a nonspecific effect rather than a consistent
finding over different tests (41). With the exception of
motor skills, which were spared in early right-sided
FLE, no systematic effect of the assumed influence of
the age at the onset of epilepsy on cognitive development
could be concluded from their data (42). The
impact of having epileptic seizures on cognition can
well be demonstrated by our postoperative findings
indicating that in seizure-free patients adjacent functions
recovered after surgery. Comparable release effects
have been also reported after temporal lobe surgery
(47). However, one should not go so far as to
conclude that all deficits are due to epileptic dysfunction
and thus reversible as has been suggested by
Boone et al. in a single case report in 1988 (48).
In summary, from the neuropsychological findings
in FLE, it appears that indeed different frontal subfunctions
can be differentiated. Nevertheless, the measures
that characterize FLE have in common the demand
of adequate response selection and initiation,
and response inhibition. This holds for tests that explicitly
assess interferences and response inhibition
but also for tests of motor skills or working memory.
Ending up again with a unique central executive function,
one may hypothesize that the particular problem
in FLE is the impairment of response selection/initiation/
inhibition with varying emphasis depending on
different functional areas. Which area is affected then
depends on the type and localization of the underlying
lesion, including the possibility that symptoms are
overshadowed by spreading epileptic dysfunction.
It is important to mention that the development of
appropriate test instruments for the assessment of
frontal lobe dysfunction is not yet complete and still
represents a challenge for neuropsychologists. Most
psychometric tests that allow quantification of test
behavior provide patients with a clear structure for
behavior, i.e., with test instructions, rules, time constraints.
This enables the patient to behave in an ordered
way and real problems with behavior organization
arising from frontal pathology are easily overlooked.
If provided with more degrees of freedom and
demands on spontaneous interactions with complex
situations, the same patient would otherwise reveal
deficits. A possible solution to this dilemma could be
to design tasks that evoke spontaneous behavior and
decisions that are up to the subject, as has been done
by Bechara et al. with the gambling task (49), by Goldberg
et al. with their cognitive bias task (50), or by
Upton and Thompson with their twenty questions
ICTAL BEHAVIOR IN FRONTAL LOBE
SEIZURES: “POSITIVE” AND
Like others before, we recently analyzed seizure
phenomena in patients with frontal lobe epilepsy by
video-EEG monitoring. The main purpose was to get
hints from seizures for differential diagnosis. On the
other hand seizures can be studied in terms of transient
dysfunctions, which are more or less circumscribed
and point to certain cerebral structures. Seizure
semiology, preserved functions, as well as impaired
functions can tell us something about the
cerebral functional organization of cognition and consciousness.
We studied “positive phenomena” in
terms of seizure semiology and “negative phenomena”
in terms of impairment when patients were neuropsychologically
tested during their seizures (51–53).
Ictal phenomena in frontal seizures are mostly positive
phenomena (see Table 2). On the one hand, this
means a nearly 1:1 relationship between discharges
and motor excitation when direct access to motor neurons
is possible in primary motor area seizures, for
example. On the other hand, this means release and
disinhibition of complex behaviors and behavior
chains when precentral areas are involved. Examples
are posturing and contraversive movements in SMA
and premotor seizures, and explosive, bizarre, and
emotional unstable behaviors in prefrontal seizures
including its mesial parts. Negative phenomena like
loss of consciousness are commonly observed in seizures
with mesial propagation and secondary generalization.
For frontal seizures one can thus conclude
that the prominent feature is impairment of executive
Ictal Frontal Seizure Semiology (N = 15)
||Nearly 1:1 manifestation of
seizure activity in myoclonic
and tonic or clonic motor
||Contraversive head and eye
|Prefrontal (including cingulate
|Explosive and complex motor
||Bizarre and hysterical behaviour
|Mesial propagation and
|Loss of consciousness
|Impaired executive control: “pathological exitation
control in terms of a pathological "hyperexcitation or
Neuropsychological examination of the cognitive
impairment during seizures can provide additional
insight into the ictal event. We performed ictal testing
in 116 patients, most of whom were candidates for
epilepsy surgery. These patients underwent ictal examinations
that included examination of orientation
reflexes (verbal, nonverbal, tactile), expressive/receptive
language (commands, naming repetition), nonverbal
reception/expression (commands and imitation),
and, finally, awareness and memory (interrogation
after the seizure). Testing was performed by the
video-EEG monitoring staff and started as soon as
possible after seizure onset. Functions were tested hierarchically
according to their complexity and testing
was continued until the seizure ended. About half of
the patients had implanted strip or depth electrodes
for invasive EEG recordings. Table 3 shows the impairment
pattern that results when distribution of ictal
EEG activity at the time of testing is considered. In
comparison to lateralized and bilateral temporal lobe
seizures, frontal lobe seizures are characterized by
prominent impairment of orientation reflexes and expressive
speech, which are typical frontal functions.
Receptive speech is often preserved. Patients can try,
for example, to follow body commands even when
they appear involved in excessive motor activity. In
contrast to left and bitemporal seizures in particular,
consciousness (awareness of any kind) and memory
|Behavioral Aspects of Frontal Lobe Epilepsy
Negative Ictal Symptoms in Focal Epilepsy (N = 116)
||Location of seizure activity
N = 29
n = 21
n = 38
N = 28
|% Impaired when tested ictally
for the test situation during the seizures are mostly
A very interesting behavior and neuropsychological
pattern of impairment can be observed in patients
with frontal nonconvulsive status epilepticus. It is important
to note that in contrast to grand mal status,
which is the repetition of the same seizure, the nature
of frontal nonconvulsive status and frontal seizures is
completely different. In contrast to frontal lobe seizures,
seizure semiology of nonconvulsive status is
dominated by negative seizure phenomena. Without
EEG recording, the epileptic nature of this state is
easily overlooked and patients appear somehow
strange since they are slowed, dysphoric, morose, and
adverse. When neuropsychologically examined during
the seizure we found in five cases consistently
generally reduced activity, fluctuating orientation, reflexive
and no self-initiated behavior, perseverations,
intrusions, apractic signs, problems to shift between
tasks, impaired working memory on a higher cognitive
level, and emotional instability (see Table 4). In
1997 we already described a single patient with a
nonconvulsive status epilepticus who showed a generalized
EEG pattern but focal cognitive deficits when
neuropsychologically tested during this state. Today,
with better diagnostic tools we would probably be
able to reinterpret this case also as frontal nonconvulsive
In contrasting frontal seizures with frontal nonconvulsive
status one could interpret the latter rather in
terms of an impaired executive control by pathological
“hyperinhibition.” Impressive recovery to normal behavior
can be observed in these patients when the
status is successfully ended by injection of diazepam.
This is thus one form of state-dependent cognitive
impairment. Another form can be seen in postictal
Because they often do not lose consciousness during
frontal lobe seizures, patients are accordingly quickly
reoriented postictally. Figure 1 shows the course of
verbal memory and decision times in pre- and postictal
memory testing after frontal lobe seizures as compared
with left/right temporal seizures and repeated
testing in healthy controls. After lateralized temporal
lobe seizures, material-specific memory impairment
can be observed for at least 1 hour after complete
reorientation. What is shown for left temporal patients
in verbal memory in Fig. 1 has its counterpart for right
temporal patients in figural memory. As for frontal
lobe seizures it is remarkable that there is no postictal
deterioration in memory nor significant slowing of
reaction times. However, when seizures secondarily
generalize, lasting memory impairment can be observed
also following frontal seizures (55).
We can conclude so far that from frontal lobe seizures,
a dysexecutive syndrome results with mostly
preserved awareness and consciousness, reflexive but
not self-initiated behavior, and a seizure semiology
dominated by a state of hyperexcitation and disinhibition
or hyperinhibition. This would confirm the impression
from neuropsychological findings that the
major problem in FLE is appropriate response selection/
initiation and inhibition of behavior. A further
Ictal Symptoms in Frontal Nonconvulsive Status Epilepticus (N = 5)
|Motor functions (including
|Generally reduced activity
||Rarely automatisms (fumbling
etc. . . .)
|Executive functions (including
|No self-initiated directed actions
||Apraxia signs in object use and
||Problems with concept
formation and shift (color/
||Impaired only when complex
mental information processing
||Emotional instability (dysphoric)
|Impaired executive control: “pathological inhibition”
FIG. 1. Preictal baseline measures and postictal course of verbal memory and decision times in patients with frontal and left or right temporal
lobe epilepsy. The bars indicate performance of healthy subjects when tested repeatedly in the same intervals.
differentiation according to lesions or foci within particular
sites of the frontal lobes can be suggested but
has not yet been proven. From a neuropsychological
point of view it is still difficult to decide whether one
central executive function or different executive functions
should be assumed. As already mentioned a
compromise is favored at the moment, which suggests
that the frontal subfunctions are constituted by similar
processes of response selection/initiation and inhibition
in different domains and modalities of behavior,
BEHAVIORAL CORRELATES OF
FRONTAL LOBE EPILEPSY
If we propose problems with behavior selection/
initiation and inhibition as a functional complex that is
affected mainly in frontal lobe epilepsy, the obvious
question is whether or not this dysfunction has a
correlate in personality and behavior.
With respect to this question we applied several
self-rating scales to a group of 95 patients with either
frontal (n = 18) or mesial (n = 77) temporal lobe
epilepsy. Epilepsy groups were matched regarding
sex, age at onset of epilepsy (mean, 11 years), and
duration of epilepsy (mean, 24 years). The BPSE “activity
subscale” was used to assess frequencies of activities
(56), depression and anxiety were assessed by
the Beck Depression Inventory (BDI) (57) and the
Zung Self Rating Anxiety Scale (SAS) (58), and personality
was assessed by the Neo Five Factor Inventory,
a German version of the NEO personality inventory
(59). Quality of life in epilepsy was assessed by a
German modified QOLIE-10 (English version: Cramer
et al. (60)), and finally we evaluated education and
employment to add some objective data.
Group comparisons considering localization and
lateralization of epilepsy revealed only slight differences
(Table 5). Patients with M-TLE as a trend
showed poorer mood and significantly increased anxiety
scores; they described themselves more active at
home, less active with respect to outdoor cultural activities,
and less open for experiences than patients
with FLE. It is important to note that, when compared
with normative data for healthy control subjects, the
result regarding outdoor cultural activities must be
interpreted in the context that patients with FLE are
more active than the controls and patients with MTLE.
Furthermore, when compared with normal data
for a healthy control group, the neuroticism score of
patients with M-TLE and the conscientiousness score
of patients with FLE appeared elevated.
As regards quality of life, patients were categorized
as having poor QOL when they showed scores below
the 25% percentile. As shown in Fig. 2 patients with
TLE generally tended to report poorer QOL than patients
with FLE. Impaired mood, memory problems,
|Behavioral Aspects of Frontal Lobe Epilepsy
|Mood (BDI SAS)
Activities (BPSE: activity subscale)
Personality (NEO FFI)
|Open for experiences
| Note. *P < 0.05.
and social limitations correspond well to the features
of TLE found with the other instruments in this evaluation.
Our current approach to behavioral problems and
personality in patients with focal epilepsies is less led
by classification systems, which may be useful in idiopathic
psychiatric disorders. As already mentioned
in the Introduction there is a long history of personality
research in epilepsy and up to now no consistent
features are discerned. So far this has been explained
by the multifactorial determination of psychiatric
problems in patients with symptomatic epilepsies. As
far as psychometric approaches are concerned, previous
studies of temporal lobe epilepsy mostly used the
MMPI (61) or, more specifically, the Bear–Fedio Inventory
(62, 63). It is our daily experience that commonly
used psychiatric scales or psychological personality
inventories largely fail to reflect objectively what
seems to the examiner clearly to be an epilepsy-related
change in personality or a behavior disorder.
At the moment we are evaluating our own clinical
personality inventory, which was empirically designed
according to a collection of behavioral problems perceived
by the clinical psychological staff at the University
Hospital of Epileptology, Bonn, Germany (64). For
preliminary analysis the questionnaire was consecutively
applied to 59 patients with TLE, 17 patients with
FLE, 9 patients with parieto-occipital epilepsy, and 44
healthy subjects. It consists of 82 questions concerning 15
different behavioral domains. The answer style is a sixstep
frequency of occurrence rating with 1 = “occurs not
at all” and 6 = “occurs very frequently.” Second-order
factor analysis resulted in six factors, which were interpreted
as follows: (1) “organic personality change” with
patients reporting communication problems, emotional
lability, being indetermined, and suspectibilty to interference,
perseverations, and hypoactivity; (2) “depressed
mood,” including depressive mood, reduced vitality,
anxiety, and insensitivity; (3) “addiction and obsession”
including addiction to legal and illegal substances, compulsion,
and obsession; (4) “extraversion” comprising
sociability, curiosity, and self-determined behavior; (5)
“aggression” comprising aggression, sensation seeking,
nonadaptive behavior, and violence; (6) “hyperactivity
and adaptivity.” When clinical data as well as sex are
taken as independent variables some interesting results
emerge (Fig. 3).
The data indicate that problems in the respective
areas are evident in 20 to 30% of the patients. Organic
personality changes are preferentially seen in left epilepsies
of either origin, as well as in women rather
than men. Addiction and obsession are more frequent
in right epilepsies and frontal epilepsies in particular.
Depressed mood is preferentially seen in patients with
hippocampal sclerosis, a finding that is in line with
one of our recent publications (65). All patients and
patients with parietal epilepsies in particular show
FIG. 2. Quality of life in FLE as compared with M-TLE. Values <
25% percentile were considered as reflecting perception of impaired
QOL. Asterisks indicate significant group differences in x2 testing.
FIG. 3. Results obtained with the clinical personality inventory. *P < 0.05. **P < 0.01.
reduced extraversion. Aggressive behavior seems
more frequent in left epilepsies, and patients with FLE
show increased hyperactivity and adaptivity, which
may parallel the finding of increased outdoor/cultural
activities and openness for experiences. It is important
to note that these results are preliminary and that
larger control groups and validation studies are still
required. However, the data indicate that the oftencited
depressive mood is not the only behavioral problem
in patients with focal epilepsy and that apart from
this there are specific behavioral aspects that appear
related to localized and lateralized lesions/or epileptic
Although no differences between patients with FLE
and TLE could be observed it is worth reporting the
results with respect to organic personality change scale
in more detail. As shown in Fig. 4 for selected items,
about 20% of the patients report that they offend others,
FIG. 4. Items extracted out of the "organic personality change"
scale of the clinical personality inventory. Bars represent the percentages
of patients with focal epilepsies reporting increased problems
in communication and interpersonal contact.
between 20 and 35% of the patients report problemswith
reception, misunderstandings, or that they were perceived
as perseverative or circumstantial, and 50% report
that their behavior irritates others. This is similar to
the “epileptic personality” and, taken together with the
depressed mood, one might as well think of the dysphoric
and paroxysmal mood disorder as has been proposed
from a more psychiatric point of view (66).
ACADEMIC ACHIEVEMENT AND
EMPLOYMENT IN FRONTAL
It is well known that patients with frontal lesions
may show unimpaired cognitive functions but nevertheless
fail on everyday demands of job and career
because of behavioral problems, unsteadiness, concentration
problems, increased susceptibility to interference,
and problems with timing and planning. Subjective
data may not reveal behavioral problems because
patients with frontal lobe lesions have been reported
to underestimate their impairments. With school
achievement and employment, however, we have indirect
markers, which allow us to infer to what extent
patients are adapted to everyday life. As indicated in
Table 6 it is not the group with FLE but that with
M-TLE that is less educated, and the job situation is
comparable in both groups.
TRAIT OR STATE
The above data suggests that patients with frontal
lobe epilepsy have behavioral disorders that appear
|Behavioral Aspects of Frontal Lobe Epilepsy
|Academic achievement level
|FLE (n = 18)
|M-TLE (n = 83)
| a x2, significant difference.
very mild as compared with those reported in patients
with frontal mass lesions. With respect to mood disorders
they appear less affected than patients with
temporal lobe epilepsy and they also show better academic
achievement. The finding that hyperactivity,
addiction, and obsession might be behavioral features
of FLE is of great interest and can be discussed as
reflecting frontal dysfunction in general and as being
in line with the behavior observed in neuropsychological
examination and during seizures. The question
that remains is how consistent the behavior in focal
epilepsies is over time.
We cannot yet conclusively answer this question on
the basis of long-term follow-up observations. The
impact of epilepsy and seizures on behavior, however,
can be estimated by comparisons of patients who after
surgery still have seizures and those who are completely
seizure free. We therefore analyzed data from
operated and nonoperated patients who participated
in a long-term follow-up study, which was originally
designed to show the cognitive development of these
patients over time (67). At the long-term follow-up
visit we also assessed depression by use of the Beck
Depression Inventory and quality of life by use of a
German modified QOLIE-10. For the present purpose
we extracted from the total database only the data for
patients with temporomesial epilepsy and hippocampal
sclerosis as compared with those with frontal lobe
epilepsy. Fifty-seven patients had mesial temporal
lobe epilepsy with hippocampal sclerosis (27 had surgery,
20 were treated conservatively) and 30 patients
had frontal lobe epilepsy (16 had surgery, 14 were
treated conservatively). Taking depression and qualityof-
life measures as the dependent variables in a multivariate
analysis with consideration of surgery, localization,
and lateralization of epilepsy as independent
variables and age and follow-up interval (mean, 56
months, 2–10 years) as covariates, seizure outcome
turned out to be the only significant predictor. Only
14% of the seizure-free patients in contrast to 51% of
those who still had seizures showed elevated depres-
scores greater than the cutoff score of 12 points. It
should be noted that 14% is much less than the usually
reported 30% of patients with focal epilepsy and depressive
mood, and that 51% clearly exceeds this number.
Comparably, 45% of the seizure-free patients reported
good quality of life with QOLIE, as compared
with only 11% of the patients who continued to have
seizures. Although these are not follow-up data and
depression and quality of life represent only two facets
of the whole range of behavior, these data show
quite impressively what a difference the presence or
absence of seizures can make. The finding parallels
recent findings in children who after successful epilepsy
surgery showed marked improvement in behavior
disorders (68). Long-term follow-up studies on
personality and behavior disorders are thus needed to
complete our understanding of the interaction between
brain damage, epilepsy, and behavior.
We can conclude that in frontal lobe epilepsy “frontal
dysfunctions” characteristically become evident in
cognition, seizures, and behavior. The main common
feature of the behavioral problems in FLE is behavior
control in terms of response selection/initiation and
inhibition. The domains in which these problems become
apparent may vary with clinical conditions. Following
our own findings hyperactivity, conscientiousness,
obsession, and addiction can be seen as behavioral
correlates of frontal lobe dysfunction in frontal
lobe epilepsy. Depression, anxiety, neuroticism, cognitive
(memory) impairment, and social limitations, in
contrast, seem to be features of mesial temporal lobe
epilepsy. However, methodological difficulties regarding
the adequacy of the clinical measures in use as
well as confounding effects of lesions, epileptic dysfunction,
AED, and psychosocial status do not yet
allow further distinctions as they are made for example
in neurobiological models about the frontal lobes
and behavior. Full-blown personality disorders are
very rare in FLE and symptoms appear rather mild as
compared with patients with mass lesions. As regards
the state/trait discussion in epilepsy, the effects of
seizure control indicate that a major component of the
observed behavioral problems is indeed state dependent.
However, follow-up evaluations are needed to
understand the contribution of lesions and epileptic
dysfunctions to behavior disorders and to demonstrate
to what extent these are reversible.
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