ARTICLE
Auteur(s) : Seetharam Raghavendra, Seyed Mirsattari, Richard S McLachlan
Department of Clinical Neurological Sciences, University
of Western Ontario, London, Canada
Article reçu le 19 Novembre 2009, accepté le 22 F�vrier 2010
Whistling during seizures is one of the most uncommon ictal
automatisms and has rarely been reported in the literature
(Lazzarino and Valassi, 1982; Tan et al., 1990; Loring
et al., 1994). Confirmation of the seizure focus is lacking
and the localizing value of this form of vocalization remains
unclear. We report here two patients with temporal lobe seizures in
whom a prominent ictal feature was whistling.
Case studies
Case 1
A 35-year-old right-handed man, had medically refractory complex
partial seizures with onset at age 14 years. The semiology of
his seizures consisted of an aura of epigastric discomfort lasting
several seconds followed by behavioural arrest, prominent
whistling, oral-alimentary automatisms, ictal speech, bipedal
automatisms and partially retained interaction with his
surroundings. He had no memory of these manifestations except for
his aura. The average frequency of seizures was two or three per
month. An equal number of auras alone occurred as simple partial
seizures. Several antiepileptic medications were tried with poor
response. At the time of pre-operative surgical evaluation, he was
taking 2,000 mg levetiracetam and 1,000 mg carbamazepine, daily. He
had no other neurological symptoms. His medical and family
histories were otherwise unremarkable and non-contributory. His
physical examination was entirely normal.
EEG monitoring showed a mild degree of focal slowing over the
right temporal region with activation of right anterior mesial
temporal spikes during sleep. During video-EEG telemetry, six
complex partial seizures manifesting with an epigastric sensation
followed by prominent whistling and other behaviour (see video
sequence) were recorded from the right temporal lobe (figure 1). MRI of the
brain was normal. Detailed neuropsychological testing showed left
hemispheric dominant language with normal attention, language and
visual spatial and verbal memory.
Following a right anterior temporal lobectomy, he has been
seizure free for two years with 500 mg daily levitiracetam.
Histopathology of the temporal lobe showed nonspecific microscopic
areas of gliosis in Ammon's horn.
Case 2
A 50-year-old left-handed man developed late onset medically
refractory complex partial seizures at the age of 45 years.
Semiology of these seizures, which occurred about six times per
week, consisted of a prominent aura of an unpleasant smell
like that of “marihuana” followed by behavioural arrest, staring,
whistling, lip smacking and bimanual automatisms lasting one
to two minutes. There was postictal anomia lasting up to several
hours on occasion. Rare generalised tonic-clonic seizures occurred
about once a year. He was otherwise healthy and neurologically
intact. No epilepsy risk factors were determined. Multiple
antiepileptic medications had been tried including phenytoin,
levitiracetam, clonapepam, topiramate and lamotrigine.
Scalp video-EEG monitoring showed a mild degree of slowing over
the left temporal regions, rare left temporal spikes and two
seizures originating from the left temporal lobe. In addition, one
seizure of similar clinical semiology, but with bilateral temporal
ictal changes and no discernible focal onset, was captured.
Subsequent invasive monitoring with bilateral subdural temporal
coverage showed interictal discharges predominantly in the left
mesial temporal region with rare independent right temporal spikes.
Four typical seizures lasting one to two or three minutes each
arose from and remained restricted to the left anterior mesial
temporal region. MRI of the brain was normal. Neuropsychological
testing showed atypical speech representation and mild visual
spatial memory impairment. Sodium amytal test showed left
hemispheric language dominance and bilateral failure on memory
testing. Left hemispheric activation for language tasks was found
on fMRI. Novelty scene encoding produced unilateral activation of
the right hippocampus and parahippocampus.
He underwent a left anterior temporal lobectomy during which
intra-operative cortical stimulation confirmed left hemispheric
language function. Pathology was consistent with mild mesial
temporal sclerosis. The patient remained seizure free at two years
follow-up. There were no significant memory or language deficits
post-operatively.
Discussion
Ictal whistling is an unusual and extremely rare manifestation of
seizures. A search of our database of more than 5,000 patients
evaluated for medically refractory seizures over the last two
decades yielded a description of ‘whistling’ on only two occasions.
Both patients had temporal lobe epilepsy with seizures from the
non-dominant hemisphere in one and the dominant hemisphere in the
other. Both remained seizure free two years after temporal
lobectomy confirming the correct lateralization and localization of
seizure onset. We have also seen prominent whistling in two other
patients, both males with temporal lobe epilepsy, one during a
postictal confusional state and the other during postictal
psychosis.
The first report of ictal whistling suggested the seizure origin
was in the frontal lobe but without clear confirmation (Lazzarino
and Valassi, 1982). Two previous reports of whistling during
temporal lobe seizures were based on finding right posterior
temporal spikes in the interictal EEG in one (Tan et al.,
1990) and, in the other, apparent right temporal lobe seizures
recorded by depth electrodes but with no change in seizures after
epilepsy surgery (Loring et al., 1994). Our cases are the
first in which seizure localization was confirmed by successful
resective surgery.
Whistling is a complex phenomenon, requiring widespread
coordination of perioral, oral and respiratory muscles. It is a
very primitive function during evolution and a number of mammals
have retained this ability. Whistling formed one of the earliest
forms of human communication and entire languages based around
whistling are still practiced (Rialland, 2005). Thus, compared to
other forms of non-speech vocalization including humming or singing
that occur in association with temporal lobe seizures (Bartolomei
et al., 2007; Kuscu et al., 2008; Horvath et al.,
2009), it is surprising that whistling is not seen more often as an
ictal automatism. This possibly relates to the complex and
widespread network involved in the neurophysiology of whistling.
The limited studies in this area suggest that whistling requires
the coordination of orofacial movements within a widely distributed
sensorimotor network including the inferior rolandic cortex,
cingulate cortex, basal ganglia, amygdala and thalamus.
A recent fMRI study showed widespread bilateral activation of
these areas as well as cerebellum during whistling (Dresel
et al., 2005). Whistling that occurs as an ictal phenomenon
may not be a particularly good lateralizing sign, but in the rare
cases when it has been described, it appears to localize seizure
onset to one or other temporal lobe.
Legend for video sequence
Disclosure
None of the authors has any conflict of interest to disclose.
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