Neuropsychological assessment in mixed connective tissue disease: comparison with systemic lupus erythematosus

The aims of the study were to assess cognitive functions (CF) in patients with mixed connective tissue disease (MCTD) and to compare MCTD patients with systemic lupus erythematosus patients with and without neuropsychiatric manifestations (NP-SLE and non-NP-SLE, respectively) in terms of CF.

Neuropsychological examination was performed in 141 patients: 30 with MCTD (24 women, 6 men), mean age: 48.07 years, 37 with non-NP-SLE (36 women, 1 man), mean age: 40.76 years and 74 with NP-SLE (68 women, 6 men), mean age: 41.97 years. Neuropsychological tests and structured interview were used. Emotional state was assessed by Hospital Anxiety and Depression Scale and clinical review.

We observed cognitive impairment in six MCTD patients (20%); in one (3%) the impairment was severe. MCTD patients achieved significantly higher results in seven out of 11 tests compared with patients with NP-SLE. MCTD and non-NP-SLE patients did not differ significantly. The differences were irrespective of premorbid IQ, education, disease duration and steroid treatment.

In the majority of MCTD patients, CF were not impaired and severe impairment was unusual. Cognitive functioning was most disturbed in NP-SLE. The cognitive deficits observed in connective tissue diseases can be connected with nervous system involvement.