1Cairo University, Cairo, Egypt
Cognitive impairment in neuromyelitis optica spectrum disorder (NMOSD) is not uncommon occurring independent from attacks and lesions. It presents in about 30-70% of NMOSD patients. Psychiatric symptoms may be initial manifestation of NMOSD, and depression is not uncommon. NMOSD patients showed global brain atrophy however it is not associated with brain or spinal lesions. Transcranial sonography (TCS) is a reliable method for assessment of third ventricular diameter and its enlargement can be used as a marker of brain atrophy and cognitive impairment. The aim of the study is to assess the cognitive functions in NMOSD and its relation to brain atrophy using transcranial sonography (TCS) for brain parenchyma.
Material(s) and Method(s):
Observational, case-control study, conducted on 42 subjects, 23 patients with NMOSD, and 19 healthy controls with matching age, sex and years of education. Participants were subjected to cognitive assessment using California verbal learning test 2nd edition (CVLT-II), Controlled Oral Ward Association Test (COWAT) and Trail Making Test-B (TMT) (oral version) and neurosonographic assessment using B-mode TCS for brain parenchyma.
Mean age of the patients with NMOSD was 35.1 ± 10.1 years with mean disease duration was 40.1 ± 51.6 months. While mean age of the healthy control was 29.8 ± 6.8 years. Female to male ratio was 21:2 and 15:4 for patients and control respectively. Mean years of education was 8.8 ± 4.5 years and 10.7 ± 0.8 years for the patients and healthy control respectively. Mean of basic EDSS for the patient was 5.22 ± 1.5. Cognitive performance was significantly worse in NMOSD group compared to healthy control. CVLT-II showed that total recall, short-delay free-recall, short-delay cued-recall, long-delay free-recall and long-delay cued-recall were significantly worse in patients with NMOSD, p value <0.0001, <0.0001, <0.0001, <0.0001 and <0.0001. Trail making test showed that patients with NMOSD had worse executive functions and longer processing speed with p value <0.0001. COWAT, either category or letter, showed no statistically significant difference between patients with NMOSD and healthy control. As regard brain atrophy, assessed by TCS, diameter of the 3rd ventricle was significantly wider among patients with NMOSD than in healthy control with p value 0.03. Rt and Lt thalami were significantly smaller in patients with NMOSD than in healthy control with p value 0.0003 and 0.03 respectively. More patients with NMOSD had interrupted median raphe than healthy control with p value 0.03. In NMOSD group, there was a statistically significant negative correlation between EDSS and scores of CVLT-II (total recall, short-delay free-recall, short-delay cued-recall, long-delay free-recall and long-delay cued-recall) as well as COWAT- letters. There was significant positive correlation between EDSS and TMT-B. No significant correlation was found between EDSS and diameter of 3rd ventricle. There was significant positive correlation between diameter of frontal horns and TMT-B. A significant negative correlation was found between diameter of 3rd ventricle scores of COWAT- letter and as well as CVLT-II total recall.
Patients with NMOSD had poorer cognitive functions than healthy control. Also, they had more brain atrophy than healthy control.