Cognitive functioning, emotional processing, mood and personality variables before and after stereotactic surgery : A study of eight 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.