Insular and caudate lesions release abnormal yawning in stroke patients

Abstract

Abnormal yawning is an underappreciated phenomenon in patients with ischemic stroke. We aimed at identifying frequently affected core regions in the supratentorial brain of stroke patients with abnormal yawning and contributing to the anatomical network concept of yawning control. Ten patients with acute anterior circulation stroke and ≥3 yawns/15 min without obvious cause were analyzed. The NIH stroke scale (NIHSS), Glasgow Coma Scale (GCS), symptom onset, period with abnormal yawning, blood oxygen saturation, glucose, body temperature, blood pressure, heart rate, and modified Rankin scale (mRS) were assessed for all patients. MRI lesion maps were segmented on diffusion-weighted images, spatially normalized, and the extent of overlap between the different stroke patterns was determined. Correlations between the period with abnormal yawning and the apparent diffusion coefficient (ADC) in the overlapping regions, total stroke volume, NIHSS and mRS were performed. Periods in which patients presented with episodes of abnormal yawning lasted on average for 58 h. Average GCS, NIHSS, and mRS scores were 12.6, 11.6, and 3.5, respectively. Clinical parameters were within normal limits. Ischemic brain lesions overlapped in nine out of ten patients: in seven patients in the insula and in seven in the caudate nucleus. The decrease of the ADC within the lesions correlated with the period with abnormal yawing (r = -0.76, Bonferroni-corrected p = 0.02). The stroke lesion intensity of the common overlapping regions in the insula and the caudate nucleus correlates with the period with abnormal yawning. The insula might be the long sought-after brain region for serotonin-mediated yawning.

Fig. 1

Lesion maps. Lesion overlay maps incorporating seven patients with common lesions in the insula (arrow MNI: x = −37, y = 7, z = 5) and seven in the caudate head (arrow MNI: x = −17, y = 14, z = 15) associated with abnormal yawning

Fig. 2

Abnormal yawning without initial DWI restrictions. (a) Evolution of the penumbra in a patient with abnormal yawning initially not related to DWI lesions in the caudate head or insula (Pat N^o 4). While cortical DWI restrictions were initially restricted to the frontal lobe (not shown) and parietal lobe, perfusion imaging revealed a widespread penumbra along the left MCA encompassing the insula and caudate head (TTP delay >4.5 s). (b) Follow-up after 48 h revealed prolonged infarction of the tissue at risk in the left insula, striatum and frontal and parietal lobe, now including the caudate head and the insula, with luxury perfusion of the infarcted tissue

Fig. 3

Abnormal yawning and clinical and neuroradiological stroke parameters. Correlations of the period length with abnormal yawning (duration of yawning [h]) with: (a) ADC values as neuroradiological surrogate marker of stroke severity, and (c) NIHSS as clinical marker of stroke severity. No correlations were found between duration of yawning and (b) neuroradiological stroke volume, and (d) mRS d7–14 as clinical outcome marker, determined between days 7–14 after stroke onset