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NEUROLOGICAL PICTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
doi: 10.1136/jnnp.2007.116376

Glossoplegia in a small cortical infarction

W

e recently observed a patient with
obvious contralateral tongue deviation with minimal lower facial paresis
caused by a small cortical infarction confirmed
by MRI. The small cortical lesion, causing
obvious tongue deviation in our patient, was
located lateral to the precentral knob which is
known as a reliable anatomical landmark for
the motor hand area. We were able to localise
the cortical area for tongue movement to the
most lateral part of the precentral gyrus lateral
to the precentral knob.
A 63-year-old, right-handed man with a
1 year history of hypertension suddenly developed dysarthria. He was alert, fully oriented
and cooperative. There was no decline in
language function. On cranial nerve examination, he was found to have tongue deviation
toward the right with minimal right facial
paresis with forehead wrinkling (fig 1A). The
masseter and temporal muscles were normal,
and soft palate movements were symmetrical.
Muscle strength in the extremities, in particular the right arm and hand, was not
decreased. MRI of the brain (fluid attenuated
inversion recovery image (FLAIR), T2 and
diffusion weighted image (DWI)) showed a
small cortical infarction in the precentral
gyrus of the left frontal lobe (fig 1B–D).
There were no other abnormalities in the
cerebrum, brainstem or cerebellum, and magnetic resonance angiography showed normal
findings. The tongue deviation and dysarthria
gradually improved but persisted 2 months
after stroke onset.
To our knowledge, this is the first report of
obvious tongue deviation with minimal lower
facial paresis caused by a small cortical
infarction confirmed by MRI. In a previous
study with supranuclear vascular lesions, the
frequency of tongue deviation was 29%, and
marked facial/brachial paresis or hemiparesis
was usually associated.1 To localise the cortical
lesion in our patient, the anatomical marking
shaped like an omega in the axial plane of the
patient’s MRI (fig 1B–D), termed the ‘‘precentral knob’’, was clearly identified in the
precentral gyrus. The small ischaemic lesion,
causing obvious tongue deviation in our
patient, was located lateral to the precentral
knob which is known to be a reliable
anatomical landmark for the motor hand
area.2 Recently, a study reported that pure
dysarthria was seen in six stroke patients with
a small cortical stroke located lateral to the
precentral knob on DWI.3 However, the area
was not clearly defined as the motor tongue
area causing pure dysarthria because contralateral tongue deviation was not noted in all
six and the lesion for pure dysarthria was
localised lateral to the precentral knob in only
two of the five patients with ischaemic stroke.
Furthermore, the lesion was not identified by
www.jnnp.com

Figure 1 (A) The protruded tongue deviating to the right about 1.5 cm from the midline. (B) Diffusion
weighted, (C) T2 weighted image and (D) fluid attenuated inversion recovery (FLAIR) magnetic
resolution images of the brain showed a small cortical infarction in the precentral gyrus of the left frontal
lobe. White and black arrows indicate the precentral knob representing the motor hand area.
conventional T2 weighted MRI in all ischaemic strokes. In contrast, on FLAIR and T2 weighted
MRI, as well as DWI, in our patient, the precentral knob was clearly identified and we were able to
localise the cortical area for tongue movement to the most lateral part of the precentral gyrus
lateral to the precentral knob.

Sung-Sang Yoon, Key-Chung Park
Department of Neurology, Kyung Hee University, School of Medicine, Seoul, Korea
Correspondence to: Professor Key-Chung Park, Department of Neurology, Kyung Hee Medical Centre,
Kyung Hee University School of Medicine, 1 Hoegi-dong, Dongdaemoon-ku, Seoul, 130-702, Korea;
kcpark67@medimail.co.kr
Competing interests: None.

REFERENCES
1 Umapathi T, Venketasubramanian N, Leck KJ, et al. Tongue deviation in acute ischaemic stroke: a study of
supranuclear twelfth cranial nerve palsy in 300 stroke patients. Cerebrovasc Dis 2000;10:462–5.
2 Yousry TA, Schmid UD, Alkadhi H, et al. Localization of the motor hand area to a knob on the precentral gyrus. A
new landmark. Brain 1997;120:141–57.
3 Kim JS, Kwon SU, Lee TG. Pure dysarthria due to small cortical stroke. Neurology 2003;60:1178–80.