Cognitive function and 99mTc-ECD brain SPECT are significantly correlated in patients with primary Sjogren syndrome: a case-control study

Objectives: To assess subclinical central nervous system (CNS) involvement in primary Sjogren syndrome (pSS), by comparing standard brain MRI, in-depth neuropsychological testing and Tc-99m-ECD brain single-photon emission computed tomography (SPECT) of patients with pSS with matched controls. Methods: 10 women (<55 years old), with pSS defined using European-American criteria, presence of anti-SSA and/or anti-SSB antibodies and no history of neuro logical involvement were prospectively investigated, and compared with 10 age-and sex-matched controls. All subjects underwent, within 1 month, brain MRI, neuropsychological testing, including overall evaluation and focal cognitive function assessment, and 99mTc-ECD brain SPECT. Results: Tc-99m-ECD brain SPECT abnormalities were significantly more common in patients with pSS (10/10) than controls (2/10; p<0.05). Cognitive dysfunctions, mainly expressed as executive and visuospatial disorders, were also significantly more common in patients with pSS (8/10) than controls (0/10; p<0.01). Notably, between-group comparisons enabled a significant correlation to be established between neuropsychological assessment and Tc-99m-ECD brain SPECT abnormalities in patients with pSS (r(s)=0.49, p<0.01). MRI abnormalities in patients and controls did not differ significantly. Conclusions: Neuropsychological testing and Tc-99m-ECD brain SPECT seem to be the most sensitive tools to detect subclinical CNS dysfunction in pSS. The strong correlation between cortical hypoperfusion in Tc-99m-ECD brain SPECT and cognitive dysfunction suggests an organic aetiology of CNS dysfunction in pSS. These data should be confirmed in a larger study.