Neurodegenerative diseases impact the structure and operation of the nervous system, causing progressive and irreparable harm. Efforts for distinguishing neurodegenerative diseases in their early stages are continuing. Despite several biomarkers being identified, there is always search for more accurate and abundant ones. Additionally, it can be difficult to pinpoint the precise neurodegenerative disorder affecting a patient as the symptoms of these conditions frequently overlap. Numerous studies have shown that pathological changes occur years before clinical signs appear. Therefore, it is crucial to discover blood‐based biomarkers for neurodegenerative diseases for easier and earlier diagnosis. Proximity extension assay is a unique proteomics method that uses antibodies linked to oligonucleotides for quantifying proteins with real‐time PCR. Proximity extension assay can identify even low‐quantity proteins using a small volume of specimens with increased sensitivity compared to conventional methods. In this article, we reviewed the employment of proximity extension assay technology to detect biomarkers or protein profiles for several neurodegenerative diseases.

Background: Essential tremor (ET) is a common chronic progressive disease, characterized by postural and action tremor. Abnormalities within the cerebello-thalamocortical pathways are thought to be involved in ET. In some studies, it was reported that there is an association between ET and hearing loss. Objective: In this study, our goal is to examine the electrophysiological changes of the structures forming the auditory pathway in ET cases, and the relationship of these changes with clinical findings and understand if the pathology underlying hearing loss in ET is cochlear or retrocochlear. Materials and Methods: One hundred sequential ET patients who had referred to Mersin University Faculty of Medicine Neurology Department, and 100 healthy individuals that are equivalent in terms of age and gender were conducted to investigate this association. Detailed medical history, neurologic examination, audiologic examination, pure-tone audiometry (PTA), tympanometry, and auditory brainstem response (ABR) analyses also known as brainstem auditory-evoked potentials were applied to all patients and controls. Results: The mean age of patients with ET was 56.38 ± 16.73, and the mean age of individuals in the control group was 56.47 ± 16.86. Nineteen of the patients with ET, and two healthy individuals from the control group had hearing problems (P < 0.001). In this study, there were no significant differences found in audiometric and ABR examinations in terms of hearing loss between the ET group and control group. However, in audiometric and ABR analyses, an increase in hearing loss was found to be correlated with an increase in tremor severity. In PTA test, hearing loss was higher in those with high-intensity tremor severity than in the group with mild tremor severity. This was statistically significant. P (KW) <0.05 Pposthoc < 0.05. In ABR analysis, it was found that there was a statistically significant difference with the increase of tremor severity at the dominant hand with: wave V latencies of the right and left ear; I-V interpeak latencies of the right ear, and III-V interpeak latencies of the right ear. The difference was between mild and moderate tremor groups. Conclusion: This study shows that there could be an impairment in inhibiting the functional transmission in the brainstem of patients with ET.

Purpose: Restless Legs Syndrome (RLS) pathophysiology involves central iron deficiency and dopaminergic dysfunction, but the role of peripheral nerves and patient-specific factors like age remains unclear. This study investigated the relationships between serum ferritin, age, and peripheral electrophysiological findings in drug-naïve RLS patients. Methods: A retrospective cohort study was conducted with 95 drug-naïve RLS patients. Comprehensive analysis included serum ferritin levels, detailed nerve conduction studies, and clinical assessments. Statistical evaluations involved subgroup comparisons (based on ferritin and EMG status), correlation analyses, and binary logistic regression to identify independent predictors of abnormal electromyography (EMG). Results: The cohort had a mean age of 53.8 years, with 14.7% having low ferritin. A striking dissociation was observed: all patients (100%) with low ferritin had normal EMG, whereas 41.2% of those with normal ferritin had abnormal EMG (p=0.002). Elderly patients were significantly more likely to exhibit abnormal EMG recordings (62.7 vs. 48.9 years, P<0.001) and had longer symptom duration. Multivariate analysis confirmed advancing age as the sole independent predictor of abnormal EMG (aOR-1:14 per year, P=0.001). Conclusion: This study demonstrates a strong association between peripheral nerve abnormalities and advanced age, particularly in patients with accompanying comorbidities, in drug-naïve RLS patients, while such abnormalities were absent in younger patients with low ferritin. These findings point to potential subgroups with differing pathophysiology. Future research should incorporate advanced electrophysiological methods to better define these subgroups and their clinical relevance.