Patients with chronic autoimmune demyelinating polyneuropathies exhibit cognitive deficits which might be associated with CSF evidence of blood-brain barrier disturbance

Abstract

Background Chronic autoimmune demyelinating polyneuropathies (CADP) result in impaired sensorimotor function. However, anecdotal clinical observations suggest the development of cognitive deficits during the course of disease. Methods We tested 16 patients with CADP (11 patients with chronic inflammatory demyelinating polyneuropathy, 4 patients with multifocal motor neuropathy and 1 patient with multifocal acquired demyelinating sensory and motor neuropathy) and 40 healthy controls (HC) with a neuropsychological test battery. Blood-brain-barrier dysfunction (BBBd) in patients was assessed retrospectively by analysing the cerebral spinal fluid (CSF) status at the time the diagnosis of CAPD was established. Results CADP patients failed on average in 1.7 out of 9 neuropsychological tests (SD ± 1.25, min. 0, max. 5). 50% of the CADP patients failed in at least two neuropsychological tests and 44.3% of the patients failed in at least two different cognitive domains. CADP patients exhibiting BBBd at the time of first diagnosis failed in more neuropsychological tests than patients with intact integrity of the BBB (p < 0.05). When compared directly with the HC group, CADP patients performed worse than HC in tests measuring information processing ability and speed as well as phonemic verbal fluency after adjusting for confounding covariates.

Chronic inflammatory demyelinating polyneurophaty: assessment of the cognitive function and quality of life

“… 4 This fact is probably due to a bias in the selection of the CG or by a very small number of individuals in the present study, for whom it was not possible to decrease the standard deviation of the tests, as it is frequently used and is already well established in cognitive assessment research with neurological patients. 4 The execution of the DSST involves the recruitment of frontoparietal areas related to selective attention processes, occipital areas related to visual attention, and cerebellum, demanding both hemispheres for most areas. 10 These outcomes reflect the recruitment of areas related to the downward control of attention, such as the middle and upper frontal gyri and the upper and lower parietal gyri.…”

“…This battery of tests, like the MMSE, was not included in the few existing studies on cognitive function in patients with CIDP. 4 5 This fact also makes comparison with their results impossible. Since MoCA is an easy-to-apply battery, it can be performed even during routine outpatient consultations, with high sensitivity for the diagnosis of mild cognitive impairment, it is an indispensable test in any study that aims to assess cognitive function and its particularities.…”

“…The average age and sex of the patients in the present study found similarity with previous studies, in which CIDP patients are on average 50 years old and mostly male. 1 4 7 8 There is still no information to explain the male predominance, 1 4 7 nor any hypothesis. 1 This finding suggests that some characteristics of certain neuropathies are independent of environmental factors and vary according to the population studied.…”

“…There are few published studies on the assessment of cognitive deficits in peripheral neuropathies and these with different applied methodologies. 4 5 Thus, the comparison between published papers is impractical.…”

“…Previously, other groups observed cognitive impairment in patients with CIDP. 4 5 However, the lack of standardized cognitive tests restrains the comparison of studies with this goal.…”