Cognitive functioning, emotional processing, mood, and personality variables before and after stereotactic surgery: a study of 8 cases with chronic neuropathic pain.

BACKGROUND: Stereotactic central lateral thalamotomy (CLT) has been applied as a treatment for chronic intractable neuropathic pain. However, it is not clear whether this intervention influences the emotional and cognitive impairments observed in patients who have chronic neuropathic pain. OBJECTIVE: To investigate neuropsychological functions and emotional processing in patients with chronic neuropathic pain compared with healthy volunteers and to explore the neuropsychiatric effect of the CLT. METHODS: We investigated pain ratings, cognitive functions, emotional processes, and personality variables before and after surgery in 8 patients with intractable neuropathic pain. Patients were tested before and 3 months after CLT by the use of neuropsychological tests; clinical scales for depression, anxiety, anhedonia, and anger regulation; a personality test; and 2 experimental tasks testing the theory of mind as well as the ability to recognize facial emotional expressions. Nine age- and sex-matched control subjects were tested once using the same procedure. RESULTS: The comparison of the patient group before surgery with the control group evidenced significant differences on the cognitive assessments, the depression and anxiety scores, as well as on the somatic complaint subscale of the personality test. Three months after CLT, patients experienced a significant improvement in their depression scores. There were no additional postsurgical cognitive impairments. CONCLUSION: For our patients with chronic neuropathic pain, CLT provided pain relief and reduction of their depression scores without causing postsurgical cognitive impairments.

Grey matter changes associated with medication-overuse headache: correlations with disease related disability and anxiety.

OBJECTIVES: Medication-overuse headache (MOH) is associated with psychiatric comorbidities. Neurobiological similarities to substance dependence have been suggested. This study investigated grey matter changes, focussing on pain and reward systems. METHODS: Using voxel-based morphometry, structural MRIs were compared between 29 patients with both, MOH and migraine, according to International Headache Society criteria, and healthy controls. The Migraine Disability Assessment (MIDAS) score was used. Anxiety and depression were screened for with the Hospital Anxiety and Depression Scale (HADS) and confirmed by a psychiatrist, using the Mini International Neuropsychiatric Interview. RESULTS: Nineteen patients (66%) had a present or past psychiatric disorder, mainly affective (N = 11) and anxiety disorders (N = 8). In all patients a significant increase of grey matter volume (GMV) was found in the periaqueductal grey matter of the midbrain, which correlated positively with the MIDAS and the HADS-anxiety subscale. A GMV increase was found bilaterally in the thalamus, and the ventral striatum. A significant GMV decrease was detected in frontal regions including orbitofrontal cortex, anterior cingulate cortex, the left and right insula, and the precuneus. CONCLUSION: These findings are consistent with dysfunction of antinociceptive systems in MOH, which is influenced by anxiety. Dysfunction of the reward system may be a neurobiological basis for dependence in a subgroup of MOH patients.