Parkinson's disease with restless legs syndrome-an in vivo corneal confocal microscopy study

Corneal Sub-Basal Nerve Plexus in Non-Diabetic Small Fiber Polyneuropathies and the Diagnostic Role of In Vivo Corneal Confocal Microscopy

In vivo corneal confocal microscopy (IVCM) allows the immediate analysis of the corneal nerve quantity and morphology. This method became, an indispensable tool for the tropism examination, as it evaluates the small fiber plexus in the cornea. The IVCM provides us with direct information on the health of the sub-basal nerve plexus and indirectly on the peripheral nerve status. It is an important tool used to investigate peripheral polyneuropathies. Small-fiber neuropathy (SFN) is a group of neurological disorders characterized by neuropathic pain symptoms and autonomic complaints due to the selective involvement of thinly myelinated Aδ-fibers and unmyelinated C-fibers. Accurate diagnosis of SFN is important as it provides a basis for etiological work-up and treatment decisions. The diagnosis of SFN is sometimes challenging as the clinical picture can be difficult to interpret and standard electromyography is normal. In cases of suspected SFN, measurement of intraepidermal nerve fiber density through a skin biopsy and/or analysis of quantitative sensory testing can enable diagnosis. The purpose of the present review is to summarize the current knowledge about corneal nerves in different SFN. Specifically, we explore the correlation between nerve density and morphology and type of SFN, disease duration, and follow-up. We will discuss the relationship between cataracts and refractive surgery and iatrogenic dry eye disease. Furthermore, these new paradigms in SFN present an opportunity for neurologists and clinical specialists in the diagnosis and monitoring the peripheral small fiber polyneuropathies.

Ocular Surface Features in Patients with Parkinson Disease on and off Treatment: A Narrative Review

Parkinson disease (PD) is a progressive, neurodegenerative disease of the central nervous system. Visual disturbance is one of the most frequent nonmotor abnormalities referred to by patients suffering from PD at early stages. Furthermore, ocular surface alterations including mainly dry eye and blink reduction represent another common finding in patients with PD. Tears of PD patients show specific alterations related to protein composition, and in vivo confocal microscopy has demonstrated profound changes in different corneal layers in this setting. These changes can be attributed not only to the disease itself, but also to the medications used for its management. In particular, signs of corneal toxicity, both at epithelial and endothelial level, are well described in the literature in PD patients receiving amantadine. Management of PD patients from the ophthalmologist's side requires knowledge of the common, but often underdiagnosed, ocular surface alterations as well as of the signs of drug toxicity. Furthermore, ocular surface biomarkers can be useful for the early diagnosis of PD as well as for monitoring the degree of neural degeneration over time.

Real-time large-area imaging of the corneal subbasal nerve plexus

The morphometric assessment of the corneal subbasal nerve plexus (SNP) by confocal microscopy holds great potential as a sensitive biomarker for various ocular and systemic conditions and diseases. Automated wide-field montages (or large-area mosaic images) of the SNP provide an opportunity to overcome the limited field of view of the available imaging systems without the need for manual, subjective image selection for morphometric characterization. However, current wide-field montaging solutions usually calculate the mosaic image after the examination session, without a reliable means for the clinician to predict or estimate the resulting mosaic image quality during the examination. This contribution describes a novel approach for a real-time creation and visualization of a mosaic image of the SNP that facilitates an informed evaluation of the quality of the acquired image data immediately at the time of recording. In cases of insufficient data quality, the examination can be aborted and repeated immediately, while the patient is still at the microscope. Online mosaicking also offers the chance to identify an overlap of the imaged tissue region with previous SNP mosaic images, which can be particularly advantageous for follow-up examinations.

Semiautomated and Automated Quantitative Analysis of Corneal Sub-Basal Nerves in Patients With DED With Ocular Pain Using IVCM

Purpose

Investigate the correlation and agreement between the results of semiautomated and fully automated quantitative analysis of the corneal sub-basal nerve plexus (SNP) in patients with dry eye disease (DED) with ocular pain using in vivo confocal microscopy (IVCM).

Method

A total of 50 voluntary participants were enrolled in this study, i.e., 25 DED patients with ocular pain and 25 healthy controls. Each patient underwent an evaluation of ocular symptoms that utilized: the Ocular Surface Disease Index (OSDI), the Ocular Pain Assessment Survey (OPAS), the tear film breakup time (TBUT) test, the Schirmer test, corneal staining, and IVCM. Five SNP images of the cornea of each eye were selected and analyzed using a semiautomated analysis software (NeuronJ) and a fully automated method (ACCMetrics) to quantify corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), and corneal nerve fiber length (CNFL).

Results

The intraclass correlation coefficient (ICC) of the CNFD (0.460 [0.382–0.532], p < 0.001), CNBD (0.608 [0.545–0.665], p < 0.001), and CNFL (0.851 [0.822–0.875], p < 0.001) represents the repeatability and consistency of measurements by the NeuronJ and ACCMetrics software. The CNFL values (r = 0.881, p < 0.001) obtained using the two methods have extremely high correlation, and similarly, the CNFD values (r = 0.669, p < 0.001) and CNBD values (r = 0.703, p < 0.001) are highly correlated. The CNFL had the biggest area under the curve (AUC; 0.747 [0.700–0.793], p < 0.001) when using ACCMetrics. In DED patients with ocular pain, the mean CNFD values for semiautomated and fully automated quantization were 23.5 ± 8.1 and 23.8 ± 8.6 n/mm²; the mean CNBD values were 46.0 ± 21.3, 35.7 ± 23.3 n/mm²; and the mean CNFL values were 19.3 ± 4.3 and 15.2 ± 3.8 mm/mm², which were significantly lower than healthy subjects (p < 0.001).

Conclusion

There is a significant correlation between the measurements obtained via ACCMetrics and NeuronJ, especially for CNFL, which can be considered as the primary indicator in the diagnosis of DED with ocular pain. The SNP of the disease was significantly lower than that of healthy subjects.

Wide-field mosaics of the corneal subbasal nerve plexus in Parkinson's disease using in vivo confocal microscopy

In vivo confocal microscopy (IVCM) is a non-invasive imaging technique facilitating real-time acquisition of images from the live cornea and its layers with high resolution (1-2 µm) and high magnification (600 to 800-fold). IVCM is extensively used to examine the cornea at a cellular level, including the subbasal nerve plexus (SBNP). IVCM of the cornea has thus gained intense interest for probing ophthalmic and systemic diseases affecting peripheral nerves. One of the main drawbacks, however, is the small field of view of IVCM, preventing an overview of SBNP architecture and necessitating subjective image sampling of small areas of the SBNP for analysis. Here, we provide a high-quality dataset of the corneal SBNP reconstructed by automated mosaicking, with an average mosaic image size corresponding to 48 individual IVCM fields of view. The mosaic dataset represents a group of 42 individuals with Parkinson's disease (PD) with and without concurrent restless leg syndrome. Additionally, mosaics from a control group (n = 13) without PD are also provided, along with clinical data for all included participants.

The pattern of the inferocentral whorl region of the corneal subbasal nerve plexus is altered with age

PURPOSE

To describe the pattern of the nerves in the inferocentral whorl region of the human corneal subbasal nerve plexus (SBNP) in health and diseases known to affect the subbasal nerves.

METHODS

Laser-scanning in vivo confocal microscopy (IVCM) was used to image the SBNP bilaterally in 91 healthy subjects, 39 subjects with type 2 diabetes mellitus (T2DM), and 43 subjects with Parkinson's disease (PD). Whorl regions were classified according to nerve orientation relative to age and health/disease status.

RESULTS

Of 346 examined eyes, 300 (86.7%) had an identifiable whorl pattern. In healthy subjects, a clockwise nerve orientation of the whorl was most common (67.9%), followed by non-rotatory or 'seam' morphology (21.4%), and counterclockwise (10.7%). The clockwise orientation was more prevalent in healthy subjects than in T2DM or PD (P < 0.001). Healthy individuals below 50 years of age had a predominantly clockwise orientation (93.8%) which was reduced to 51.9% in those over 50 years (P < 0.001). Age but not disease status explained whorl orientation in T2DM and PD groups. Moreover, whorl orientation is bilaterally clockwise in the young, but adopts other orientations and becomes asymmetric across eyes with age. Finally, we report reflective 'dot-like' features confined to the whorl region of the subbasal plexus, sometimes appearing in close association with subbasal nerves and present in 84-93% of examined eyes regardless of disease status, eye or sex.

CONCLUSION

Subbasal nerves in the inferocentral whorl region are predominantly clockwise in young, healthy corneas. With aging and conditions of T2DM and PD, counterclockwise and non-rotatory configurations increase in prevalence, and bilateral symmetry is lost. Mechanisms regulating these changes warrant further investigation.

The relationship between sleep disorders, anxiety, depression, and cognitive function with restless legs syndrome (RLS) in the elderly

OBJECTIVES

Restless legs syndrome (RLS) has a significant effect on sleep and quality of life. Delays in diagnosis and treatment are frequent due to a lack of awareness. In this study, a clinical analysis was performed to examine the relationship between sleep, mood, and cognitive function in RLS.

METHODS

According to the Pittsburgh Sleep Quality Index score (PSQI), patients with RLS were divided into a sleep disorders group (SD, PSQI > 7) and non-sleep disorders group (NSD, PSQI ≤ 7). Healthy controls were selected as a control group matched for age, cultural background, and marital status. We compared differences between the three groups using the Hamilton Anxiety Scale (HAMA), Hamilton Depression (HAMD), Mini-Mental State Examination (MMSE), and Montreal Cognitive Assessment (MoCA). The SD and NSD groups were also assessed with the Restless Leg Syndrome Rating Scale (RLSRS) and the severity of RLS between the two groups was compared. The analysis used t-test, ANOVA, and Pearson correlation.

RESULTS

(1) Among the 54 RLS patients, 30 people in the control group, 35 patients with sleep disorders (SD, 65%), and 19 patients without sleep disorders (NSD, 35%), there were no significant differences in age, educational level, marital status, or trauma history. (2) The comparison results of the case group (SD and NSD) and the control group showed highly significant differences (P < 0.01) in the PSQI-HAMA-HAMD score but no significant differences between the NSD group, the SD group, and the control group in MMSE score. There was no difference between the NSD group and the control group in the MoCA, but a significant difference (P < 0.05) between the SD group and the control group was found. (3) The comparison between the NSD and the SD groups revealed significant differences in the RLSRS, HAMA, and HAMD scores (P < 0.05), but there were no statistical differences (P > 0.05) between two groups on MMSE and MoCA score. (4) Correlation and regression showed that there was a linear correlation between PSQI scores and RLSRS and HAMD scores in patients with RLS (P < 0.05). The regression equation was PSQI =  - 2.393 + 0.494 RLSRS + 0.170 HAMD.

CONCLUSIONS

RLS patients were prone to sleep disorders, anxiety, and depression. Sleep disorders increased with the severity of the RLS and had some influence on the patient's cognitive function. Sleep disorders were closely related to RLSRS and HAMD.