Neuropathic pain in multiple sclerosis can manifest itself in the form of the Lhermitte phenomenon, short-term unpleasant sensations along the spine that occur when the head is bent. The purpose of this study is to investigate the factors that act as predictors of the Lhermitte phenomenon and their frequency in multiple sclerosis. 308 patients with multiple sclerosis were involved in the study, 258 of them agreed to follow-up, of them there were 67 men (26.0%) and 191 women (74.0%), aged 21 to 60 years. Out of the total cases, 187 (72.5%) patient had the relapsing-remitting type of multiple sclerosis, 2 (0.8%) had primary progressive type, and 69 (26.7%) showed secondary progressive type. Among the 258 patients who initially agreed to participate in the study at the Centre, 18 (7.0%) individuals discontinued their involvement during the first year, and 13 (5.0%) individuals prematurely withdrew from the study during the second year due to various reasons.
Among the characteristics of multiple sclerosis, the age of the patient when diagnosed, the duration and the type of course, and the overall assessment of neurological deficit were determined. Psychopathological and cognitive states, socio-demographic factors, and comorbid pathology were assessed using appropriate scales. Statistical research methods were employed to analyze the collected data.
The results indicate that the risk of developing the Lhermitte phenomenon remains relatively consistent over a two-year period: 2.5% in the first year and 2.3% in the second year. Pain associated with the Lhermitte phenomenon is most commonly experienced in the neck (63.6%), followed by the upper back (54.6%), lower back (72.7%), and least frequently in the upper limbs (18.2%) and lower limbs (36.4%). The Lhermitte phenomenon typically spreads to two or three affected areas of the body in 33.3% and 48.2% of cases, respectively. The most commonly used descriptors for the Lhermitte phenomenon are "shooting" (72.7%), "tingling" (18.2%), and "crawling ants" (9.1%).
No significant differences in social, demographic, neuropsychological, and neurocognitive characteristics were observed between patients with and without Lhermitte phenomenon. According to the results of univariate Cox regression analysis, we has found that during the 2-year period, an increase in the duration of the disease for each subsequent year is associated with a decrease in the relative risk of Lhermitte phenomenon by 1.15 times (1.02-1.29, p=0.02). In patients with multiple sclerosis, the average risk of experiencing the Lhermitte phenomenon remains consistent at approximately 2.3-2.5% per year throughout the course of the disease.
Patients who have a short history of multiple sclerosis are a risk group for the occurrence of the Lhermitte phenomenon. It is quite difficult to explain the regularity we have identified, for its clarification a detailed study of a special additional study is necessary. But, in any case, from a practical point of view, patients in the early stages of multiple sclerosis can be considered as a group of increased risk for the occurrence of the Lhermitte phenomenon.
