http://www.healthrising.org/blog/2016/09/09/optic-nerve-fibromyalgia-neurodegenerative/
excerpt:
The study being discussed in this article is here:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0161574
(open access)
excerpt:
by Cort Johnson | Sep 9, 2016
We know that fibromyalgia is a central nervous system disorder; the question is whether we can do away with the “central” part and call it simply a nervous system disorder. It’s clear that somewhere around 40% of people with FM also have small nerve fiber damage (SFN). That neuropathy describes not only the disappearance of some of the small nerves in the skin and eyes but the thinning of the remaining ones in the skin. That last finding is so unusual that it’s been suggested that the small nerve fiber problems found in FM be called something else entirely ( small nerve pathology)
A major question facing SFN researchers in fibromyalgia is how important the small nerve fiber problems are to fibromyalgia. Daniel Clauw, a prominent FM researcher, believes the SFN is probably incidental and has little to do with the core pathology of the disease. Others believe that the process causing the loss and thinning of the unmyelinated fibers in FM probably plays a core role in the disease.
This Spanish study examined nerve thickness in a new part of the body – the retina of the eye. Until now nerve studies have focused on the peripheral nerves found in the body. Because this part of the eye is considered to be part of the central nervous system, this study was the first to examined potential small nerve problems in that area.
The Study
Fibromyalgia Is Correlated with Retinal Nerve Fiber Layer Thinning Elena Garcia-Martin1,2*, Javier Garcia-Campayo2,3, Marta Puebla-Guedea2,3, Francisco J. Ascaso2,4, Miguel Roca5, Fernando Gutierrez-Ruiz1,2, Elisa Vilades1,2, Vicente Polo1,2, Jose M. Larrosa1,2, Luis E. Pablo1,2, Maria Satue1,2This study measured axon diameter in nine different areas of the eye.
With 116 age and sex-matched patients and a 144 controls it was a nice-sized study. It aimed to determine if retinal nerve fiber thinning had occurred in three sections of the eye, and if it had, if disease duration, severity, etc. were associated with it. (They subdivided the FM participants into people with severe and “mild” FM.) They used several different kinds of optical coherence tomography (OCT) in the study.
Results
The study found that even patients with “mild” FM displayed “subclinical” thinning of the retinal nerves in the nasal and temporal sectors of the eye. The degree of thinning was not significantly greater in people with longer duration or more severe FM, but was greater in the “biologic FM” subset; i.e., people with FM who did not display anxiety or mood disorders, than in FM patients with mood disorders. (Natelson has found a similarly curiously pattern in ME/CFS: ME/CFS patients without mood disorders display more neurological abnormalities than those with mood disorders.)
Noting that the retinal and optic nerves in the eye derive from brain tissue during development, and thus are considered part of the central nervous system, the authors suggested that their findings suggested that the eyes of FM patients could function as windows into whatever central nervous system problems present...
The study being discussed in this article is here:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0161574
(open access)
Abstract
Objective
To investigate whether fibromyalgia induces axonal damage in the optic nerve that can be detected using optical coherence tomography (OCT), as the retinal nerve fiber layer (RNFL) is atrophied in patients with fibromyalgia compared with controls.
Methods
Fibromyalgia patients (n = 116) and age-matched healthy controls (n = 144) were included in this observational and prospective cohort study. All subjects underwent visual acuity measurement and structural analysis of the RNFL using two OCT devices (Cirrus and Spectralis). Fibromyalgia patients were evaluated according to Giesecke’s fibromyalgia subgroups, the Fibromyalgia Impact Questionnaire (FIQ), and the European Quality of Life-5 Dimensions (EQ5D) scale. We compared the differences between fibromyalgia patients and controls, and analyzed the correlations between OCT measurements, disease duration, fibromyalgia subgroups, severity, and quality of life. The impact on quality of life in fibromyalgia subgroups and in patients with different disease severity was also analyzed.
Results
A significant decrease in the RNFL was detected in fibromyalgia patients compared with controls using the two OCT devices: Cirrus OCT ganglion cell layer analysis registered a significant decrease in the minimum thickness of the inner plexiform layer (74.99±16.63 vs 79.36±3.38 μm, respectively; p = 0.023), nasal inferior, temporal inferior and temporal superior sectors (p = 0.040; 0.011 and 0.046 respectively). The Glaucoma application of the Spectralis OCT revealed thinning in the nasal, temporal inferior and temporal superior sectors (p = 0.009, 0.006, and 0.002 respectively) of fibromyalgia patients and the Axonal application in all sectors, except the nasal superior and temporal sectors. The odds ratio (OR) to estimate the size effect of FM in RNFL thickness was 1.39. RNFL atrophy was detected in patients with FIQ scores <60 (patients in early disease stages) compared with controls in the temporal inferior sector (78.74±17.75 vs 81.65±3.61; p = 0.020) and the temporal superior sector (78.20±14.50 vs 80.74±3.88; p = 0.039) with Cirrus OCT; in the temporal inferior sector (145.85±24.32 vs 150.18±19.71; p = 0.012) and temporal superior sector (131.54±20.53 vs 138.13±16.67; p = 0.002) with the Glaucoma application of the Spectralis OCT; and in all sectors, except the average, nasal superior, and temporal sectors, and parameters with the Axonal application of the Spectralis OCT. Temporal inferior RNFL thickness was significantly reduced in patients with severe fibromyalgia (FIQ≥60) compared with patients with mild fibromyalgia (FIQ<60; 145.85±24.32 vs 138.99±18.09 μm, respectively; 145.43±13.21 vs 139.85±13.09 μm, p = 0.032 with the Glaucoma application and p = 0.021 with the Axonal application). The subgroup with biologic fibromyalgia exhibited significant thinning in the temporal inferior and superior sectors (115.17±20.82 μm and 117.05±24.19 μm, respectively) compared with the depressive (130.83±22.97 μm and 127.71±26.10 μm, respectively) and atypical (128.60±26.54 μm and 125.55±23.65 μm, respectively) subgroups (p = 0.005 and 0.001 respectively).
Conclusions
Fibromyalgia causes subclinical axonal damage in the RNFL that can be detected using innocuous and non-invasive OCT, even in the early disease stages. The impact on the RNFL in the temporal sectors is greater in patients with biologic fibromyalgia, suggesting the presence of neurodegenerative processes in this subgroup of patients with fibromyalgia.
