Visual function resists early neurodegeneration in the visual system in primary progressive multiple sclerosis.

BACKGROUND: Neurodegeneration in multiple sclerosis (MS) affects the visual system but dynamics and pathomechanisms over several years especially in primary progressive MS (PPMS) are not fully understood. METHODS: We assessed longitudinal changes in visual function, retinal neurodegeneration using optical coherence tomography, MRI and serum NfL (sNfL) levels in a prospective PPMS cohort and matched healthy controls. We investigated the changes over time, correlations between outcomes and with loss of visual function. RESULTS: We followed 81 patients with PPMS (mean disease duration 5.9 years) over 2.7 years on average. Retinal nerve fibre layer thickness (RNFL) was reduced in comparison with controls (90.1 vs 97.8 µm; p<0.001). Visual function quantified by the area under the log contrast sensitivity function (AULCSF) remained stable over a continuous loss of RNFL (0.46 µm/year, 95% CI 0.10 to 0.82; p=0.015) up until a mean turning point of 91 µm from which the AULCSF deteriorated. Intereye RNFL asymmetry above 6 µm, suggestive of subclinical optic neuritis, occurred in 15 patients and was related to lower AULCSF but occurred also in 5 out of 44 controls. Patients with an AULCSF progression had a faster increase in Expanded Disability Status Scale (beta=0.17/year, p=0.043). sNfL levels were elevated in patients (12.2 pg/mL vs 8.0 pg/mL, p<0.001), but remained stable during follow-up (beta=-0.14 pg/mL/year, p=0.291) and were not associated with other outcomes. CONCLUSION: Whereas neurodegeneration in the anterior visual system is already present at onset, visual function is not impaired until a certain turning point. sNfL is not correlated with structural or functional impairment in the visual system.

Cognitive impairment in multiple sclerosis does not affect reliability and validity of self-report health measures.

Patient self-report health measures have received increasing recognition as supplementary outcome parameters in multiple sclerosis (MS). Given the high prevalence of cognitive problems in this population, reliability and validity of self-report instruments in patient groups with cognitive impairment is essential, especially when using such scales longitudinally. A sample of 80 MS patients with cognitive dysfunction according to Symbol Digit Modalities Test (SDMT) score and 107 unimpaired patients were included in the analyses. Data was available from the Hamburg Quality of Life Questionnaire in Multiple Sclerosis (HAQUAMS), the Hospital Anxiety and Depression Scale (HADS), clinical rating scores [Expanded Disability Status Scale (EDSS) and FS (Functional Status) scales, CAMBS (Cambridge MS Basic Score)] and objective tests of upper and lower limb function [Timed 8 Meter Walk (T8) and Nine Hole Peg Test (9HPT)). Both self-report questionnaires showed satisfactory internal consistencies and retest reliability. Pattern and magnitude of correlations with other health status measures supported the validity of both instruments. However, there was a marked discrepancy between subjective and objective measures of cognitive function. Cognitively impaired patients furthermore showed significantly higher depression and anxiety as well as lower quality of life (QoL). The report provides evidence that QoL and affective symptomatology can be reliably assessed in MS patients with cognitive dysfunction. The common pattern of poor correlation between self-rated and objective cognitive function thus appears to be a result of the patients' (adaptive or maladaptive) coping mechanisms rather than being due to inaccurate measurement.

Prolactin stimulation in multiple sclerosis--an indicator of disease subtypes and activity?

Prolactin (PRL) belongs to the growth and lactogenic hormone family and has potent immunomodulating properties. Mild hyperprolactinemia has been found to enhance several autoimmune diseases and increased PRL plasma levels have been described in the experimental multiple sclerosis (MS) model while the PRL antagonist bromocriptine was able to suppress the disease. As studies of PRL serum levels in MS have led to conflicting results we investigated further the question of prolactin alterations in MS. We correlated PRL baseline values in a large sample of 132 MS patients with disease course and activity. Furthermore, inhibitory (bromocriptine) and stimulatory (metoclopramide) tests were performed in a subsample (n = 39) to gain functional information. We found no correlation of baseline values with disease course or activity. Nevertheless in the regression analysis of stimulatory test results, 14% of the variance was attributable to disease activity. In conclusion PRL does not seem to be relevant as an activity marker in the whole MS population.