Comparison of evoked vs. spontaneous tics in a patient with trigeminal neuralgia (tic doloureux)

A 53-year old woman with tic doloureaux, affecting her right maxillary division of the trigeminal nerve (V2), could elicit shooting pains by slightly tapping her teeth when off medication. The pains, which she normally rated as > 6/10 on a visual analog scale (VAS), were electric shock-like in nature. She had no other spontaneous or ongoing background pain affecting the region. Based on her ability to elicit these tics, functional magnetic resonance imaging (fMRI) was performed while she produced brief shocks every 2 minutes on cue (evoked pain) over a 20 min period. In addition, she had 1–2 spontaneous shocks manifested between these evoked pains over the course of functional image acquisition. Increased fMRI activation for both evoked and spontaneous tics was observed throughout cortical and subcortical structures commonly observed in experimental pain studies with healthy subjects; including the primary somatosensory cortex, insula, anterior cingulate, and thalamus. Spontaneous tics produced more decrease in signals in a number of regions including the posterior cingulate cortex and amygdala, suggesting that regions known to be involved in expectation/anticipation may have been activated for the evoked, but not spontaneous, tics. In this patient there were large increases in activation observed in the frontal regions, including the anterior cingulate cortex and the basal ganglia. Spontaneous tics showed increased activation in classic aversion circuitry that may contribute to increased levels of anxiety. We believe that this is the first report of functional imaging of brain changes in tic-doloureaux

Comparison of evoked vs. spontaneous tics in a patient with trigeminal neuralgia (tic doloureux)

Abstract A 53-year old woman with tic doloureaux, affecting her right maxillary division of the trigeminal nerve (V2), could elicit shooting pains by slightly tapping her teeth when off medication. The pains, which she normally rated as > 6/10 on a visual analog scale (VAS), were electric shock-like in nature. She had no other spontaneous or ongoing background pain affecting the region. Based on her ability to elicit these tics, functional magnetic resonance imaging (fMRI) was performed while she produced brief shocks every 2 minutes on cue (evoked pain) over a 20 min period. In addition, she had 1–2 spontaneous shocks manifested between these evoked pains over the course of functional image acquisition. Increased fMRI activation for both evoked and spontaneous tics was observed throughout cortical and subcortical structures commonly observed in experimental pain studies with healthy subjects; including the primary somatosensory cortex, insula, anterior cingulate, and thalamus. Spontaneous tics produced more decrease in signals in a number of regions including the posterior cingulate cortex and amygdala, suggesting that regions known to be involved in expectation/anticipation may have been activated for the evoked, but not spontaneous, tics. In this patient there were large increases in activation observed in the frontal regions, including the anterior cingulate cortex and the basal ganglia. Spontaneous tics showed increased activation in classic aversion circuitry that may contribute to increased levels of anxiety. We believe that this is the first report of functional imaging of brain changes in tic-doloureaux.</p

Comparison of evoked vs. spontaneous tics in a patient with trigeminal neuralgia (tic doloureux)-1

<p><b>Copyright information:</b></p><p>Taken from "Comparison of evoked vs. spontaneous tics in a patient with trigeminal neuralgia (tic doloureux)"</p><p>http://www.molecularpain.com/content/3/1/34</p><p>Molecular Pain 2007;3():34-34.</p><p>Published online 6 Nov 2007</p><p>PMCID:PMC2217520.</p><p></p>al regions including anterior cingulate (ACC), insula (Ins), middle and inferior frontal (MFG, IFG), medial temporal gyrus (MTG) and inferior parietal lobe (IPL) regions show significant activation (P < 0.0001). Subcortical regions showing significant activation include the thalamus (Thal) and pontine nuclei (PN). Notably, no significant activation was observed in the cerebellum (see text). Numbers indicated the anterior posterior, sagittal or horizontal plane of the brain slice. R = Right and L = Left

Comparison of evoked vs. spontaneous tics in a patient with trigeminal neuralgia (tic doloureux)-3

<p><b>Copyright information:</b></p><p>Taken from "Comparison of evoked vs. spontaneous tics in a patient with trigeminal neuralgia (tic doloureux)"</p><p>http://www.molecularpain.com/content/3/1/34</p><p>Molecular Pain 2007;3():34-34.</p><p>Published online 6 Nov 2007</p><p>PMCID:PMC2217520.</p><p></p> Ins – Insula; Amy – amygdala; Thal – thalamus; PN – pontine nuclei. R – right; L – left; P – posterior; A – anterior