title: Altered pain and thermal sensation in subjects with isolated parietal and insular cortical lesions.
abstract: Studies of sensory function following cortical lesions have often included lesions which multiple cortical, white matter, and thalamic structures. We now test the hypothesis that lesions anatomically constrained to particular insular and parietal structures and their subjacent white matter are associated with different patterns of sensory loss. Sensory loss was measured by quantitative sensory testing (QST), and evaluated statistically within patients relative to normal values. All seven subjects with insular and/or parietal lesions demonstrated thermal hypoesthesia, although the etiology of the lesions was heterogeneous. Cold and heat hypoalgesia were only found in the subject with the most extensive parietal and insular lesion, which occurred in utero. Cold allodynia occurred clinically and by thresholds in two subjects with isolated ischemic lesions of the posterior insular/retroinsular cortex, and by thresholds in two subjects with a lesion of parietal cortex with little or no insular involvement. Central pain occurred in the two subjects with clinical allodynia secondary to isolated lesions of the posterior insular/retroinsular cortex, which spared the anterior and posterior parietal cortex. These results suggest that nonpainful cold and heat sensations are jointly mediated by parietal and insular cortical structures so that lesions anywhere in this system may diminish sensitivity. In contrast, thermal pain is more robust requiring larger cortical lesions of these same structures to produce hypoalgesia. In addition, cold allodynia can result from restricted lesions that also produce thermal hypoesthesia, but not from all such lesions.
authors: Division of Perioperative Care and Emergency Medicine, Rudolf Magus Institute of Neuroscience, Pain Clinic, University Medical Center Utrecht, Utrecht, Netherlands.
authors: D S
authors: DS
authors: Veldhuijzen
authors: J D
authors: JD
authors: Greenspan
authors: J H
authors: JH
authors: Kim
authors: F A
authors: FA
authors: Lenz
mesh_terms: D000328:Adult; D000344:Afferent Pathways / Q000503:physiopathology; D000368:Aged; D001930:Brain Injuries / Q000503:physiopathology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000293:injuries* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology; D013697:Thermosensing / Q000502:physiology*