Cohort study on Somatoform Disorders in Parkinson’s Disease and Dementia with Lewy Bodies

Objective: assessment of somatoform disorder (SFMD) prevalence and impact in PD and DLB. Methods: SFMD were assessed by direct observation of symptoms in the year coincident (±6 months) with definite diagnosis of PD, DLB, AD, MSA, PSP, FTD and by interviews with patients, caregivers, General Practitioners (GPs), reviews of prior hospital admissions, in a cohort of 942 patients with neurodegenerative disorders. Matched groups of PD and DLB patients without vs. with SFMD were selected for comparisons and followed-up over 4 years. Results: The frequency of SFMD was higher in DLB (15 patients, 12%) and PD (29 patients, 7%) than in other neurodegenerative diseases (0-3%). SFMD consisted of conversion motor or sensory disorders, often accompanied by delusional thought content; in one patient catatonic symptoms were observed concomitantly with PD diagnosis. Evidence of SFMD symptoms, preceding diagnosis by 6 months-10 years was obtained in 28 PD and all DLB patients. 22 PD patients and all DLB patients could be followed for 4 years. SFMD symptoms recurred during follow-up, with catatonic signs developing in 9 PD and 8 DLB patients. Most baseline demographic and clinical features did not differ between subjects with or without SFMD. Decline of cognitive function was greater in PD-SFMD patients than in those without SFMD (p<0.01); it was comparable to that observed in DLB. Conclusions: The frequency of SFMD (with catatonic signs) in PD and DLB suggests that SFMD symptoms should be investigated in these diseases and might constitute a predictive factor for the development of dementia.