Sensory dysfunction in SMA type 2 and 3 - adaptive mechanism or concomitant target of damage?

BACKGROUND: The motor neuron survival protein performs numerous cellular functions; hence, spinal muscular atrophy (SMA) is considered to be a multi-organ disease with possible sensory system damage. The controversy surrounding the presence of sensory disturbances, prompted us to conduct standard electrophysiological studies and assess the sensory thresholds for different modalities in adults with SMA types 2 and 3. The study group consisted of 44 adult SMA patients (types 2 and 3). All patients underwent neurological examination using the Hammersmith Functional Motor Scale - Expanded (HFMSE). Standard sensory electrophysiological studies in the ulnar nerve and the estimation of vibratory, temperature, and warm- and cold-induced pain thresholds with temperature dispersion assessment were performed using quantitative sensory testing (QST). RESULTS: The most repeatable result was the high amplitude of the sensory nerve action potentials (SNAP) in SMA patients compared to controls. This was higher in type 2 patients compared to type 3a and 3b patients and patients with low HFSME scores. Patients with SMA, especially type 3b presented a longer sensory latency and slower conduction velocity than did controls. Cold pain threshold was higher and warm dispersion larger in SMA. The vibratory limit was higher in patients with high HFSME scores. CONCLUSIONS: A high SNAP amplitude suggests sensory fibre hyperactivity, which may be based on overactivation of metabolic pathways as an adaptive mechanism in response to SMN protein deficiency with additionally coexisting small C- and A-delta fibre damage. SMA patients seem to have a concomitant, mild demyelinating process present at the early SMA stage.

Central nervous system involvement in chronic inflammatory demyelinating polyradiculoneuropathy-MRS and DTI study.

Objective: The current research aimed to analyze the alterations within the motor cortex and pyramidal pathways and their association with the degree of damage within the peripheral nerve fibers in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). To achieve that goal, we investigated the microstructural changes within the pyramidal white matter tracts using diffusion tensor imaging (DTI) parameters, evaluated metabolic alterations in both precentral gyri using magnetic resonance spectroscopy (MRS) ratios, and correlated them with the neurographic findings in patients with CIDP. Methods: The spectroscopic ratios of NAA/Cr, Cho/Cr, and mI/Cr from both precentral gyri and the values of fractional anisotropy (FA), axial diffusivity (AD), and mean diffusivity (MD) from both of the corticospinal tracts were correlated with the results of neurological and neurographic findings. The comparison of DTI parameters between the patients and controls was performed using Student's t-test or the Mann-Whitney U test. Due to the lack of normal distribution of most variables, Spearman's Rho rank coefficient was used to test all correlations. All analyses were performed at a significant level of alpha = 0.05 using STATISTICA 13.3. Results: Compared to the control group (CG), the patient group showed significantly lower ratios of NAA/Cr (1.66 ± 0.11 vs. 1.61 ± 0.15; p = 0.022), higher ratios of ml/Cr in the right precentral gyrus (0.57 ± 0.15 vs. 0.61 ± 0.08; p = 0.005), and higher levels of Cho/Cr within the left precentral gyrus (0.83 ± 0.09 vs. 0.88 ± 0.14, p = 0.012). The DTI parameters of MD from the right CST and AD from the right and left CSTs showed a strong positive correlation (0.52-0.53) with the sural sensory nerve action potential (SNAP) latency of the right sural nerve. There were no other significant correlations between other DTI and MRS parameters and neurographic results. Significance: In our study, significant metabolic alterations were found in the precentral gyri in patients with CIDP without clinical symptoms of central nervous system involvement. The revealed changes reflected neuronal loss or dysfunction, myelin degradation, and increased gliosis. Our results suggest coexisting CNS damage in these patients and may provide a new insight into the still unknown pathomechanism of CIDP.

miR-31-5p as a Potential Circulating Biomarker and Tracer of Clinical Improvement for Chronic Inflammatory Demyelinating Polyneuropathy.

Background: MicroRNAs are endogenous, small noncoding RNA molecules that play a pivotal role in the regulation of gene expression. MicroRNAs are involved in many biological processes such as proliferation, cell differentiation, neovascularization, and apoptosis. Studies on microRNA expression may contribute to a better understanding of the pathomechanism of chronic inflammatory demyelinating polyneuropathy (CIDP) and consequently enable the development of new therapeutic measures using antisense miRNAs (antagomirs). In this study, we evaluated the level of miR-31-5p in the serum of patients with CIDP and its correlation with the miR-31-5p level and clinical presentation and electrophysiological and biochemical parameters. Methods: The study group consisted of 48 patients, mean age 61.60 ± 11.76, who fulfilled the diagnostic criteria of a typical variant of CIDP. The expression of miR-31-5p in patient serum probes was investigated by droplet digital PCR. The results were correlated with neurophysiological findings and the patient's clinical and biochemical parameters. Results: The mean copy number of miRNA-31 in 100 µl serum was 1288.64 ± 2001.02 in the CIDP group of patients, while in the control group, it was 3743.09 ± 4026.90. There was a significant positive correlation (0.426) between IgIV treatment duration and miR-31-5p expression. Patients without IgIV treatment showed significantly lower levels of miR-31 compared to the treated group (259.44 ± 304.02 vs. 1559.48 ± 2168.45; p = 0.002). The group of patients with body weight > 80 kg showed statistically significantly lower levels of miRNA-31-5p than the patients with lower body weight (934.37 ± 1739.66 vs. 1784.62 ± 2271.62, respectively; p = 0.014). Similarly, the patients with elevated cerebrospinal fluid (CSF) protein levels had significantly higher miRNA-31-5p expression than those with normal protein levels (1393.93 ± 1932.27 vs. 987.38 ± 2364.10, respectively; p = 0.044). Conclusion: The results may support the hypothesis that miR-31-5p is strongly involved in the autoimmune process in CIDP. The positive correlation between higher miR-31-5p levels and duration of IVIg treatment may be an additional factor explaining the efficacy of prolonged IVIg therapy in CIDP.

Motor fiber function in spinal muscular atrophy-analysis of conduction velocity distribution.

Objectives: The motor neuron survival protein, which is deficient in spinal muscular atrophy (SMA), performs numerous cellular functions. Currently, SMA is believed to be a multi-organ disease, including lesion of various structures of the central and peripheral nervous systems. Motor nerve damage, especially in milder SMA types, is controversial. This prompted the conduct of the electrophysiological studies in adults with SMA types 2 and 3 presented in this paper. Methods: The study group consisted of 44 adult patients with SMA types 2 and 3. All patients underwent neurological examination with Hammersmith Functional Motor Scale-Expanded (HFMSE) assessment. Standard electrophysiological studies in the ulnar nerve and conduction velocity distribution (CVD) tests were performed in all patients and controls. Results: A prolongation of the distal latency and lowering of the motor potential amplitude with no changes in CVD were found in the whole patient group. There were no dependencies on the number of gene copies. Patients with low HFSME value had slower standard conduction velocity, CVD in upper and median quartiles, and narrower CVD spread; in milder SMA, CVD spread was greater than in controls. Interpretation: The significant reduction in motor response amplitude in SMA seems to be primarily related to motor neuron loss and directly proportional to its severity. The coexisting rearrangement in the peripheral nerve structure is present in SMA, and this could be partially caused by a coexisting demyelinating process. Nerve remodeling mainly affects large fibers and occurs in more severe SMA types with significant disability.

The Relevance of Collision Tests and Quantitative Sensory Testing in Diagnostics and Postoperative Outcome Prediction in Carpal Tunnel Syndrome.

Background: The gold standards for the diagnosis and treatment of carpal tunnel syndrome (CTS) and its outcome are undecided. Using clinical and electrophysiological methods, we tried to establish which fibers achieved full postoperative recovery, and the possibility of using non-standard electrophysiological tests as outcome predictors. Methods: The study group consisted of 35 patients and controls. The Historical-Objective Scale, standard neurography, conduction velocity distribution tests (CVD), and quantitative sensory testing (QST) were performed before and after CTS surgery. Results: Clinical improvement was observed on average in 54.3% of the patients, higher in less advanced CTS. All parameters improved significantly after surgery, except for CVD; most remained worse than in the controls. Only QST parameters fully returned to normal limits. Patient age and CTS severity were important in the estimation of the risk of no improvement. Conclusions: The efficiency of minimally invasive CTS surgery is higher in younger patients with less advanced CTS. Complete recovery was present only in small fibers; larger fibers could most likely be responsible for residual signs. We did not notice any benefits in CTS diagnosis using methods of small fiber assessment. QST seemed to be useful in the diagnosis of residual signs, and in deciding upon possible reoperation.

Visual Evoked Potentials as Potential Biomarkers of Visual Function in Patients with Primary Sjögren's Syndrome.

Visual evoked potentials (VEP) are changes in potentials that arise in the central nervous system. In the interpretation of the VEP test results, it is assumed that the elongation of the latency time is caused by the demyelination of the nerve fibers, and the axon damage is responsible for the decrease in the amplitude. The observed VEP deviations are not specific for specific diseases, but indicate disturbances in visual conductivity. VEP may play a diagnostic role in the early detection of visual involvement. The aim of the study was the functioning of visual pathway assessment on the basis of visual evoked potentials (VEP) examination, in patients with primary Sjögren's Syndrome (pSS), without focal symptoms of central nervous system disorder. The effect of disease activity, as assessed by clinical parameters and antibody levels (anti-Ro52, SSA, and SSB), on the central nervous system was also evaluated. Thirty-two consecutive patient with pSS (31 females, 1 male) were included in the study. VEP was performed at baseline, and after 6 (T6) years. Their results were compared longitudinally between the baseline and T6, depending on the duration of the disease and treatment. The immunological activity of pSS was also analyzed. The group of patients showed a significant prolongation of the P100 implicit time (105.5 ± 5.1 vs. 100.6 ± 3.9; p = 0.000) and a significant higher the P100-N145 amplitude (12.3 ± 4.1 vs. 9.4 ± 3.0; p = 0.000). Abnormalities in electrophysiological parameters of VEP at baseline correlated with presentation of anti-Ro52 antibodies and aching joints. At baseline, the P100 implicit time was shorter for the patients with pSS than for those at T6 (105.50 ± 5.1 vs. 109.37 ± 5.67; p = 0.002). pSS patients without CNS involvement presented with dysfunction of visual pathway, as revealed by VEP abnormalities. Relationships were found between VEP parameters and with present of anti-Ro52 antibodies and aching joints. VEP may be a useful method for assessment and monitoring of subclinical visual deficit in the course of pSS.

Correlations between Electrophysiological Parameters, Lymphocyte Distribution and Cytokine Levels in Patients with Chronic Demyelinating Inflammatory Polyneuropathy.

The goal of this study was to analyse, in relation to electrophysiological results, the distribution of lymphocyte subpopulations and the level of cytokines in patients with the typical form of chronic demyelinating inflammatory polyneuropathy (CIDP) before immunoglobulin treatment. The study group consisted of 60 patients (52 men, eight women), with a mean age 64.8 ± 11.2, who fulfilled the diagnostic criteria for the typical variant of CIDP, with (23 patients) and without (37 patients) diabetes mellitus. We analysed the results of the neurophysiological tests, and correlated them with the leukocyte subpopulations, and cytokine levels. In CIDP patients, IL-6, IL-2, IL-4 and TNF-α levels were significantly increased compared to the control group. Fifty patients had decreased levels of T CD8+ lymphocytes, and 51 patients had increased levels of CD4+ lymphocytes. An increased CD4+/CD8+ ratio was also found. Negative correlations were observed mainly between compound muscle action potential (CMAP) amplitudes and cytokine levels. The study enabled the conclusion that electrophysiological parameters in CIDP patients are closely related to the autoimmune process, but without any clear differences between patients with and without diabetes mellitus. Correlations found in the study indicated that axonal degeneration might be independent of the demyelinating process and might be caused by direct inflammatory infiltration.

Myasthenia Gravis-An Analysis of Multimodal Evoked Potentials.

INTRODUCTION: The aim of this study is a comprehensive analysis of the parameters of exogenous evoked potentials (visual, brainstem auditory, and somatosensory) in patients with myasthenia gravis (MG), a prototype of both neuromuscular junction disease and autoimmune disease. The study also seeks to isolate electrophysiological changes that may indicate disorders within the central and/or peripheral nervous system. METHODS: A total of forty-two consecutive patients with myasthenia gravis (24 women, 18 men) were included in the study. All of the patients underwent EP examination. MR images were also analyzed. RESULTS: In the group of MG patients, the latency of P100 (113.9 ± 13.9; p < 0.0001) VEP, wave III (3.92 ± 0.29; p = 0.015), wave V (5.93 ± 0.32; <0.0001), interlatency III-V (2.00 ± 0.12; p < 0.0001), interlatency I-V (4.20 ± 0.28; p < 0.001) BAEP, and all components of SEP (N9, P10, N13, P16, N20, P22) were significantly longer. Mean wave I and V amplitude BAEP were relatively lower. CONCLUSIONS: The results of the study suggest the presence of disturbances in the bioelectric activities of the central and peripheral nervous system in MG patients.

The Use of Quantitative Sensation Testing to Identify the Physiological Differences Between the Median and Ulnar Nerves.

INTRODUCTION: Similarities in morphology, physiological function, and neurophysiological findings between median and ulnar nerves are not unequivocal. Our previous study confirmed differences in motor fiber parameters between these nerves in healthy persons. We made an attempt to assess and compare the physiological parameters of different sensation modalities (temperature, pain, and vibration) in median and ulnar nerves. METHODS: The study was performed in 31 healthy, right-handed volunteers: 17 women, 14 men, mean age 44.8 ± 15.5 years. Standard sensory conduction tests in the median and ulnar nerves were performed together with the estimation of vibratory, temperature, and warm- and cold-induced pain thresholds in the C7 and C8 dermatomes on the palm, using quantitative sensory testing. RESULTS: There were no statistically significant differences in the standard sensory conduction test in the median and ulnar nerves across the whole group: between right and left hands, and between women and men. We revealed differences in the temperature and pain thresholds between these nerves, mainly in low temperature perception. There were no differences in estimated thresholds between sides or in female and male groups. The vibratory limits did not differ significantly between nerves, and subgroups. CONCLUSION: The study confirmed the differences in the physiological sensory perception between the median and ulnar nerves. The median nerve is more sensitive to temperature stimulation than the ulnar nerve, but simultaneously less sensitive to pain-inducing temperature stimuli. These findings should be considered during the examination of hand nerve pathology.

The impact of chronic co-exposure to different heavy metals on small fibers of peripheral nerves. A study of metal industry workers.

BACKGROUND: Chronic exposure to heavy metals affects various organs, among them the brain and peripheral nerves. Polyneuropathy is mainly length-dependent with predominantly sensory symptoms. There have been few studies on small fiber neuropathy due to heavy metal intoxication. METHODS: We investigated 41 metal industry workers, mean age 51.3 ± 10.5 years, with at least 5 years' professional exposure to heavy metals, and 36 age- and sex-matched healthy controls. We performed neurological examinations, and assessed blood levels of cadmium, lead, and zinc protoporphyrin, urine levels of arsenic, standard, sensory and motor electrophysiological tests in the ulnar and peroneal nerves, sympathetic skin responses from the palm and foot, and quantitative sensation testing from dermatomes C8 and S1. DISCUSSION: The results of standard conduction tests of all nerves significantly differed between groups. The latency of sympathetic skin responses achieved from the foot was also statistically significantly prolonged in the study group. Significant differences were seen in both C8 and S1 regions for temperature and pain thresholds, and for vibratory threshold only in the S1 region, while the dispersions of low and high temperatures were important exclusively in the C8 region. CONCLUSIONS: We can conclude that co-exposure to many heavy metals results in explicit impairment of peripheral nerves. The lesion is more pronounced within small fibers and is predominantly connected with greater impairment of temperature-dependent pain thresholds. The evaluation of small fiber function should be considered in the early diagnosis of toxic polyneuropathy or in low-dose exposure to heavy metals.

Predictive factors in post-stroke epilepsy: Retrospective analysis.

BACKGROUND: Cerebrovascular disease is an important cause of epilepsy. The incidence may significantly vary (from 2.3% to 43%). Post-stroke seizures occur within 2 weeks of stroke onset (as early-onset seizures) or 2 weeks after a stroke (as late-onset seizures). OBJECTIVES: To retrospectively evaluate and differentiate predictive factors for post-stroke seizures. MATERIAL AND METHODS: We retrospectively analyzed the medical histories of 164 adult patients diagnosed with post-stroke seizures but no epilepsy recognized prior to the stroke who were hospitalized at the Neurology Clinic of Wroclaw Medical University between 2012 and 2018. The seizures were classified according to the criteria of the International League Against Epilepsy (ILAE) from 2017. The relevant demographic data, type of stroke (ischemic/hemorrhagic), time of occurrence of seizures in relation to the type of stroke, score on the modified Rankin Scale, presence of cardiovascular risk factors, electroencephalography (EEG) recording, and antiepileptic treatment (AED) were collected. In the case of ischemic stroke (IS), the size of the stroke lesion was rated on the ASPECTS scale. RESULTS: The study involved 164 patients (average age = 68.83 years), including 86 men (average age = 66.2 years). In 20 out of 164 patients, the seizures were associated with hemorrhagic stroke (HS); in 144 out of 164 patients, the post-stroke epilepsy was associated with IS. Generalized tonic-clonic seizures occurred in 101 out of 164 patients, focal aware seizures occurred in 19 out of 164 patients and focal impaired-awareness seizures occurred in 44 out of 164 patients. CONCLUSIONS: Our study has confirmed that generalized seizures occur mostly after an IS and are late complications of it. Early-onset seizures occur mostly after HS associated with severe disability. Seizures are more likely to happen due to the cortical location of the stroke. There is a shift from generalized to focal seizures with an increase in the extent of IS as evaluated using the ASPECTS scale.

Multimodal Evoked Potentials as Potential Biomarkers of Disease Activity in Patients With Clinically Isolated Syndrome.

OBJECTIVE: There is an ongoing search for markers useful in monitoring and predicting disease activity at the early stage of multiple sclerosis (MS). The goals of this study were to prospectively evaluate the changes in parameters of multimodal evoked potentials (EP) and cognition within a 3-year follow-up period in patients with clinically isolated syndrome (CIS), and to assess the prognostic value of baseline findings with regard to the disease outcomes. METHODS: In 29 patients (20 women, nine men, mean age 31.1) multimodal (visual, brainstem auditory, somatosensory, event-related) EP and neuropsychological tests (NT) were performed at baseline (T0) and after 1 (T1) and 3 (T3) years. Their results were compared longitudinally between baseline, T1, and T3. Baseline results confirmed conversion of CIS into multiple sclerosis (MS) and disability level at T1 and T3 using multiple comparisons and a logistic regression model. RESULTS: Apart from mean N13/P16 SEP (somatosensory evoked potentials) amplitude (lower at T1 and T3 than at baseline (T0 1.02 ± 0.37 µV, T1 0.90 ± 0.26 µV, T3 0.74 ± 0.32 µV, p < 0.05 for both comparisons), no significant changes of EP or NT parameters were found in longitudinal assessment. Baseline P300 Pz latency was longer for the patients with MS than for those with CIS at T1 (352.69 vs. 325.56 ms). No predictive value was shown for any of the analyzed baseline variables with regard to conversion from CIS into MS. SIGNIFICANCE: Baseline ERP abnormalities were associated with their short-term conversion into MS. ERP are worth considering in multimodal EP evaluation at the early stage of MS.

Abnormality of multimodal evoked potentials in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

INTRODUCTION: Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune disease of the peripheral nervous system, sometimes including the central nervous system. The aim of the study was the assessment of the prevalence of central sensory impairment and its reliance on peripheral nerve damage in patients with CIDP. MATERIAL AND METHODS: Multimodal (visual-VEP, brainstem auditory-BAEP, somatosensory-SEP) evoked potentials (EPs) were studied in 24 patients diagnosed with CIDP. The results were compared with neurographic parameters of sensory responses. The control group consisted of 35 healthy volunteers selected with respect to age and sex. RESULTS: Mean latency of most components of EP were considerably prolonged in patients compared with the control group. There were no correlations between the P100 VEP latency and the peripheral sensory parameters. Statistically significant negative correlations were obtained between BAEP and SEP responses and the amplitude and sensory conduction velocity of peripheral nerves. The inter-latencies were also longer. CONCLUSIONS: The authors indicated to the possibility of central sensory involvement in patients with CIDP, especially based on the prolonged inter-latency of BAEPs with simultaneously confirmed root affection. The severity of central damage correlates with the degree of peripheral nerve impairment.

Seasonal variations in the occurrence of transient global amnesia (TGA).

BACKGROUND: Transient global amnesia (TGA) is a rare, benign condition characterised by a sudden deficit of anterograde and retrograde memory that usually lasts for a few hours and is not accompanied by other focal neurological symptoms or signs. Its aetiology is still unclear. Various events or activities may trigger TGA. Evidence of seasonal variations in the appearance of TGA is inconsistent. METHODS: We retrospectively analysed the medical history of 114 adult patients with diagnosed TGA, hospitalised at two neurology departments in Wroclaw from 2008 to 2014. We reviewed risk factors, trigger points, and occurrence in each month of the year in our patient population. RESULTS: Over this seven-year period, 114 patients were diagnosed with TGA. The annual occurrence ranged from 13 to 22 hospitalisations. The mean age of the patients was 64 years. There were 36 TGA events in men and 78 in women. TGA occurred most frequently in spring (36%) and summer (30%), with the incidence peaking during March. CONCLUSIONS: Our findings suggest that there is a relationship between the season of the year and the probability of TGA.

Saharan green corridors and Middle Pleistocene hominin dispersals across the Eastern Desert, Sudan.

The Sahara Desert episodically became a space available for hominins in the Pleistocene. Mostly, desert conditions prevailed during the interpluvial periods, which were only periodically interrupted by enhanced precipitation during pluvial or interglacial periods. Responding to Quaternary climatic changes, hominin dispersal was channeled through vegetated corridors. This manuscript introduces a recently discovered group of Acheulean and Middle Stone Age sites far from the Nile Valley in the Eastern Desert (Sudan), referred to as Eastern Desert Atbara River (EDAR). The ∼5 m stratigraphy of the area is divided into three units (Units I-III) bounded by erosion surfaces. Each contains archaeological horizons. The EDAR area has rich surface sites with Acheulean horizons under the surface, singular finds of hand-axes within stratigraphic context in exposures, and large Acheulean sites partly exposed and destroyed by the gold mining activity. Optically stimulated luminescence (OSL) dating of Acheulean and MSA horizons from the EDAR 135 site indicates that the sedimentary deposits with stone artifacts were formed during the Middle Pleistocene between Marine Isotope Stages (MIS) 7 (pluvial) and 6 (interpluvial). Based on the OSL dating from the top of Unit IB, Acheulean artifact-bearing sedimentary deposits from overlying Unit IIA are younger than ca. 231 ka. Unit IA is the oldest Acheulean horizon in the EDAR area, not yet dated but definitively older than ca. 231 ka. An MSA horizon found in fluvial sediment was dated to be between 156 and 181 ka by OSL. The EDAR Pleistocene archaeological sites provide evidence for the presence of additional corridor(s) across Nubia, which connects the early hominin dispersals from the Nile and Atbara River systems to the Red Sea coast.

Use of collision tests to identify physiological differences between the median and ulnar nerves.

INTRODUCTION: Median and ulnar nerves are used in comparative electrophysiological studies. We analyzed the conduction values in these hand nerves in healthy volunteers to find any physiological differences between them. METHODS: We performed standard conduction studies and conduction velocity distribution (CVD) tests with estimation of 3 quartiles in 31 healthy right-handed volunteers (17 women, 14 men) with a mean age of 44.8 ± 15.5 years. RESULTS: The conduction velocities in all quartiles of CVD tests were statistically faster in the ulnar nerve (P < 0.00001), with no differences in the spread of conduction values and no differences between sides. In the ulnar nerve, CVD velocities in all quartiles were faster in the female group (P < 0.05). DISCUSSION: The ulnar nerve has more fibers conducting with high velocities than does the median nerve. Electrophysiological comparisons between hand nerves must be performed carefully. Muscle Nerve 59:470-474, 2019.

Parameters of Somatosensory Evoked Potentials in Patients with Primary SjÓ§gren's Syndrome: Preliminary Results.

Primary Sjogren's syndrome (pSS) is a chronic autoimmune disease. The aim of the study was to establish whether in patients with pSS without central nervous system (CNS) involvement, the function of the central portion of the sensory pathway can be challenged. In 33 patients with pSS without clinical features of CNS damage and normal head computed tomography scan, somatosensory evoked potentials (SEP) were studied. The results were compared to other clinical parameters of the disease, particularly to immunological status. The control group consisted of 20 healthy volunteers. Mean latency of all components of SEP was considerably prolonged in patients compared to the control group. Mean interpeak latency N20-N13 (duration of central conduction TT) did not differ significantly between the groups. However, in the study group, mean amplitude of N20P22 and N13P16 was significantly higher compared to healthy individuals. In patients with pSS, significant differences in SEP parameters depending on the duration of the disease and presence of SSA and SSB antibodies were noted. The authors confirmed CNS involvement often observed in patients with pSS. They also showed dysfunction of the central sensory neuron as a difference in the amplitude of cortical response, which indicates subclinical damage to the CNS.