Norwegian Sami differs significantly from other Norwegians according to their HLA profile.

This study reports extensive genomic data for both human leukocyte antigen (HLA) class I and II loci in Norwegian Sami, a native population living in the northwest of Europe. The Sami have a distinct culture and their own languages, which belong to the Uralic linguistic family. Norwegian Sami (n = 200) were typed at the DNA level for the HLA-A, -C, -B, -DRB1 and -DQB1 loci, and compared with a non-Sami Norwegian population (n = 576). The two populations exhibited some common genetic features but also differed significantly at all HLA loci. The most significantly deviating allele frequencies were an increase of HLA-A*03, -B*27, -DRB1*08 and -DQB1*04 and a decrease of HLA-A*01, C*01, -DRB1*04 and -DQB1*02 among Sami compared with non-Sami Norwegians. The Sami showed no deviation from Hardy-Weinberg equilibrium. The hypothesis of selective neutrality was rejected at all loci except for the A- and C- loci for the Sami. HLA haplotype frequencies also differed between the two populations. The most common extended HLA haplotypes were A*02-B*27-C*01-DR*08-DQB1*04 in the Sami and A*01-B*08-C*07-DR*03-DQB1*02 in the other Norwegians. Genetic distance analyses indicated that the Norwegian Sami were highly differentiated from other Europeans and were most closely related to Finns whose language also belongs to the Uralic linguistic family. In conclusion, the Norwegian Sami and the non-Sami Norwegians were significantly different at all HLA loci. Our results can be explained by the fact that the two populations have different origins and that the Sami population has remained smaller and more isolated than its neighbors.

Aspects of peripheral nerve involvement in patients with treated hypothyroidism.

BACKGROUND: We studied involvement of large and small nerve fibres in patients with hypothyroidism and symptoms and signs of polyneuropathy. METHODS: Sixteen patients with established diagnosis of hypothyroidism were extracted from a patient population participating in a 'polyneuropathy study'. In addition, seven patients with other additional potential causes of polyneuropathy than hypothyroidism were investigated. The patients underwent neurological examination, routine blood tests, nerve conduction studies (NCS), quantitative sensory testing (QST) and skin biopsies with assessment of intraepidermal nerve fibre (IENF) density. RESULTS: Sixty-three per cent of the patients with 'pure' hypothyroidism had abnormalities on NCS, 25% had reduced IENF density and 31% had abnormalities on QST. Four patients (25%) met criteria for small fibre polyneuropathy, the other (75%) were classified as having mixed fibre polyneuropathy. There were no differences in the amount of abnormalities on NCS, QST and skin biopsy between patients with hypothyroidism and those with hypothyroidism and other potential causes of polyneuropathy. CONCLUSIONS: The majority of patients with hypothyroidism had involvement of both large and small nerve fibres. However, some patients had isolated small fibre polyneuropathy. Patients with 'pure' hypothyroidism had essentially the same degree of peripheral nerve fibre involvement as those with other additional causes of polyneuropathy.

European Federation of Neurological Societies/Peripheral Nerve Society Guideline on the use of skin biopsy in the diagnosis of small fiber neuropathy. Report of a joint task force of the European Federation of Neurological Societies and the Peripheral Nerve Society.

BACKGROUND: Revision of the guidelines on the use of skin biopsy in the diagnosis of peripheral neuropathy, published in 2005, has become appropriate owing to publication of more relevant articles. Most of the new studies focused on small fiber neuropathy (SFN), a subtype of neuropathy for which the diagnosis was first developed through skin biopsy examination. This revision focuses on the use of this technique to diagnose SFN. METHODS: Task force members searched the Medline database from 2005, the year of the publication of the first EFNS guideline, to June 30th, 2009. All pertinent articles were rated according to the EFNS and PNS guidance. After a consensus meeting, the task force members created a manuscript that was subsequently revised by two experts (JML and JVS) in the field of peripheral neuropathy and clinical neurophysiology, who were not previously involved in the use of skin biopsy. RESULTS AND CONCLUSIONS: Distal leg skin biopsy with quantification of the linear density of intraepidermal nerve fibers (IENF), using generally agreed upon counting rules, is a reliable and efficient technique to assess the diagnosis of SFN (Recommendation Level A). Normative reference values are available for bright-field immunohistochemistry (Recommendation Level A) but not yet for confocal immunofluorescence or the blister technique. The morphometric analysis of IENF density, either performed with bright-field or immunofluorescence microscopy, should always refer to normative values matched for age (Recommendation Level A). Newly established laboratories should undergo adequate training in a well-established skin biopsy laboratory and provide their own stratified for age and gender normative values, intra- and interobserver reliability, and interlaboratory agreement. Quality control of the procedure at all levels is mandatory (Good Practice Point). Procedures to quantify subepidermal nerve fibers and autonomic innervated structures, including erector pili muscles, and skin vessels, are under development but need to be confirmed by further studies. Sweat gland innervation can be examined using an unbiased stereologic technique recently proposed (Recommendation Level B). A reduced IENF density is associated with the risk of developing neuropathic pain (Recommendation Level B), but it does not correlate with its intensity. Serial skin biopsies might be useful for detecting early changes of IENF density, which predict the progression of neuropathy, and to assess degeneration and regeneration of IENF (Recommendation Level C). However, further studies are warranted to confirm its potential usefulness as an outcome measure in clinical practice and research. Skin biopsy has not so far been useful for identifying the etiology of SFN. Finally, we emphasize that 3-mm skin biopsy at the ankle is a safe procedure based on the experience of 10 laboratories reporting absence of serious side effects in approximately 35,000 biopsies and a mere 0.19% incidence of non-serious side effects in about 15 years of practice (Good Practice Point).

Quantitative sensory testing in patients with polyneuropathy and healthy individuals.

AIMS: Elderly individuals and patients with polyneuropathy often feel heat pain or burning sensation on quantitative sensory testing (QST) of warm perception distally in the lower limbs. We therefore studied heat pain threshold (HPT), warm perception threshold (WPT) and the difference between heat pain and warm perception thresholds in 48 patients with symptoms and signs of polyneuropathy matched according to age and gender with 48 healthy persons. METHODS: QST (using method of limits) was performed on the distal calf and the dorsal foot. RESULTS: Particularly in the neuropathy group several individuals (58%) had an unpleasant feeling, often burning, when the thresholds according to the WPT algorithm were recorded. Difference between heat pain and warm perception thresholds in the lower calf of the patients was 3.9 +/- 3.5 and 5.8 +/- 3.4 degrees C in the controls (P = 0.012), and on the foot 3.8 +/- 2.8 vs 5.3 +/- 3.6 degrees C (P = 0.02). CONCLUSIONS: When performing QST it is important to assess also quality features of warm perception, such as burning and heat pain sensation.

Idiopathic polyneuropathy and impaired glucose metabolism in a Norwegian patient series.

BACKGROUND AND PURPOSE: North American studies have indicated a high prevalence of impaired glucose tolerance (IGT) in patients with sensory polyneuropathy. We searched for the occurrence of IGT in a Norwegian patient material with polyneuropathy. METHODS: Seventy patients with symptoms and signs of sensory polyneuropathy were included. Cases with known causes of neuropathy were excluded. All patients underwent a 2 h oral glucose tolerance test (OGTT). Nerve conduction studies (NCS), quantitative sensory testing (QST) and skin biopsy with assessment of intra-epidermal nerve fibre (IENF) density were performed. RESULTS: Sixteen patients (23%) had impaired glucose metabolism (IGM): 2 (3%) were found to have diabetes, 9 (13%) had IGT, 3 (4%) had impaired fasting glucose (IFG) and 2 (3%) both IFG and IGT. About 62% of the patients with IGM and polyneuropathy and 50% of those with chronic idiopathic axonal polyneuropathy (CIAP) had abnormalities on NCS. Reduction of IENF occurred in 37% of the patients with IGM and 43% of those with CIAP. CONCLUSIONS: Patients with polyneuropathy and IGM had essentially the same degree of involvement of small and large nerve fibres as patients with CIAP. IGT seems less frequent in Norwegian patients with polyneuropathy than reported in North American populations.

Outdoor activities and diet in childhood and adolescence relate to MS risk above the Arctic Circle.

BACKGROUND: A relationship between the latitude related distribution of multiple sclerosis (MS) and exposure to sunlight has long been considered. Higher sun exposure during early life has been associated with decreased risk of MS. OBJECTIVE: Since Norway is an exception to the latitude gradient of MS prevalence, we tested here whether sunlight exposure or vitamin D-related dietary factors in childhood and adolescence are associated with the risk of MS. METHODS: Retrospective recall questionnaire data from 152 MS patients and 402 population controls born at and living at latitudes 66-71 degrees N were analysed by means of conditional logistic regression analysis accounting for the matching variables age, sex, and place of birth. RESULTS: Increased outdoor activities during summer in early life were associated with a decreased risk of MS, most pronounced at ages 16-20 years (odds ratio (OR) 0.55, 95% CI 0.39-0.78, p = 0.001, adjusted for intake of fish and cod-liver oil). A protective effect of supplementation with cod-liver oil was suggested in the subgroup that reported low summer outdoor activities (OR 0.57, 95% CI 0.31-1.05, p = 0.072). Consumption of fish three or more times a week was also associated with reduced risk of MS (OR 0.55, 95% CI 0.33-0.93, p = 0.024). CONCLUSION: Summer outdoor activities in childhood and adolescence are associated with a reduced risk of MS even north of the Arctic Circle. Supplemental cod-liver oil may be protective when sun exposure is less, suggesting that both climate and diet may interact to influence MS risk at a population level.

Detection of cerebral embolic signals in patients with systemic lupus erythematosus.

BACKGROUND: Involvement of the CNS in systemic lupus erythematosus (SLE) is caused by several pathogenic mechanisms including cerebral embolism. AIM: To measure the frequency of microembolic signals (MES) by using transcranial Doppler (TCD) ultrasound and to assess their association with cerebral infarction, neuropsychological dysfunction, and biochemical, sonographic and clinical variables in an unselected group of patients with SLE. METHODS: A 1-h TCD recording from the middle cerebral artery was carried out in 55 patients with SLE having a mean age of 46 (SD 13) years. MRI of the brain, carotid artery ultrasonography with intima-media thickness and atherosclerotic plaque assessments were carried out in addition to a broad biochemical and clinical assessment. All patients underwent a neuropsychological assessment. RESULTS: Of the 55 patients, MES were detected in 5 (9%) and cerebral infarcts were found in 9 (18%). A significant association was found between MES and cerebral infarcts and considerably more neuropsychological deficits were found in MES-positive patients compared with the negative group. MES were not associated with other clinical, sonographic and biochemical factors believed to be associated with cerebral embolism. CONCLUSIONS: Cerebral embolism may be one of the important mechanisms responsible for the high prevalence of cerebrovascular events and the neuropsychological deficits observed in patients with SLE. Although the number of MES-positive patients was small, the lack of a significant association between MES and other known risk factors for MES suggests a complex pathogenesis for the embolisation in these patients.

Progressive central and peripheral demyelinating disease of adult onset in a Norwegian family.

OBJECTIVE: To describe the clinical features of a Norwegian family with a combined central and peripheral demyelinating disease. DESIGN: Multiple case report. SUBJECTS AND MATERIALS: Three generations of a Norwegian family. Medical records were available for all 9 members of the second generation and 5 affected members in the third generation. RESULTS: At least 5 members had clinical features, neuroimaging findings, and electrophysiologic signs indicating a chronic progressive disorder affecting both the central and peripheral nervous systems. The clinical symptoms developed between the ages of 30 and 70 years in affected family members, who gradually developed sensory loss, muscle deterioration, and distal weakness in all extremities, unsteady gait, and dysarthria. Five of 9 persons in the second generation had strokes and experienced mental deterioration. The initial stroke episodes were recognized between the ages of 54 and 68 years, and death occurred between the ages of 62 and 75 years. In 7 subjects, cerebrospinal fluid protein levels were increased, and in 5 agar gel electrophoresis indicated blood-brain barrier dysfunction. Seven family members had neuroimaging signs of a widespread white matter disorder. In 4 subjects, neurophysiological investigations indicated a polyneuropathy, and in 3 subjects, results from a sural nerve biopsy showed a demyelinating neuropathy. There was no evidence of co-inheritance with genetic markers of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (19p), PMP22 (17q), APP (21q), CMTX1 (Xq), or PLP (Xq). CONCLUSIONS: Progressive central and peripheral demyelinating disease seems to be a distinct type of hereditary adult-onset demyelinating disorder affecting both the peripheral and central nervous systems. Its exact nature remains unknown.

Peripheral neuropathy in systemic lupus erythematosus.

We studied 33 consecutive patients with systemic lupus erythematosus (SLE) for neuropathy by employing the Neuropathy Symptom Score (NSS), Neurological Disability Score (NDS), EMG and nerve conduction velocity (NCV) studies, and determinations of vibration thresholds (VT). Polyneuropathy defined as NCV abnormalities of two or more nerves occurred in seven patients (21%). Neuropathic symptoms showed a poor correlation with NCV and VT, while clinical neuropathic signs, VT, and NCV correlated with each other in most instances. When reporting frequencies of neuropathy in SLE, NCV studies should be used as a basis. NSS, NDS, and VT give additional quantifiable information and can be useful in the follow-up of patients and for evaluating the response to therapy.

Peripheral neuropathy in primary Sjögren's syndrome.

Sjögren's syndrome (dryness of eyes, mouth, and other mucous membranes) may be associated with disease of joints, blood, internal organs, skin, and central and peripheral nervous systems. We reviewed 33 cases of primary Sjögren's syndrome and peripheral neuropathy evaluated by neurologic examinations and EMG at the Mayo Clinic from 1976 to 1988, and studied sural nerve biopsy specimens in 11 of them. Symmetric sensorimotor polyneuropathy occurred most frequently, followed by symmetric sensory neuropathy. Autonomic neuropathy, mononeuropathy, or cranial neuropathy (especially trigeminal neuropathy) was superimposed on generalized neuropathy in approximately one-fourth of patients. The course generally was slowly progressive, except for a few patients who may have improved with prednisone therapy. Although spinal ganglion involvement might have accounted for some of the clinical and neurophysiologic findings, we found evidence that necrotizing vasculitis was involved in fiber degeneration. All nerve biopsies revealed perivascular inflammatory infiltrates and other vessel abnormalities, which were diagnostic in two cases and strongly suggestive of necrotizing vasculitis in six cases. Axonal degeneration predominated over demyelination and sometimes was focal or multifocal. In neuropathy of unknown cause, particularly if it is sensory, autonomic, or involves trigeminal nerve, consider Sjögren's syndrome.

The clinical significance of sleep apnoea in workers exposed to organic solvents: implications for the diagnosis of organic solvent encephalopathy.

Among 51 patients referred for investigation of possible organic solvent encephalopathy 20 (39%) had pathological sleep apnoea [apnoea index (AI) greater than 5], compared with 5 of 16 house painters exposed to solvents (31%) who were screened for the disorder, and 1 of 18 (6%) age-matched controls. Twelve of the patients with AI greater than 5 were retested after 2 or more weeks without exposure to solvents, and showed a significant drop in AI. Likewise, significantly lower AI was seen in patients who were no longer exposed to solvents, compared with recently exposed patients. The implications of these findings for diagnostic evaluation of solvent encephalopathy and sleep apnoea are discussed.

Malignant glioma and sensorimotor neuropathy.

A case of sensorimotor neuropathy in a male with malignant glioma is reported. The symptoms of peripheral motor and sensory disturbances preceeded those of the intracranial tumor. The history, clinical findings, electrophysiological and histopathological results are presented, as well as immunological data. A possible causal relationship between glioma and peripheral neuropathy is discussed.

Sleep apnoea and organic solvent exposure.

Fifteen patients referred for the evaluation of possible organic solvent encephalopathy were studied by clinical polysomnography. Seven had more than 30 apnoeas per night and an apnoea index of higher than 5, thus fulfilling the commonly used criteria of the sleep apnoea syndrome. Another group of eight workers exposed to trichlorethane, examined without prior knowledge of their individual symptoms, showed a significantly elevated number of sleep apnoeas compared with nine controls. The results indicate that organic solvent exposure can cause sleep apnoea.

Multiple sclerosis in North Norway, and first appearance in an indigenous population.

This study was performed to determine the prevalence of multiple sclerosis (MS) in 1993 and annual incidence rates 1983-1992, and to examine whether the disease occurs among the Sami people. According to earlier reports the two northernmost counties of Norway, Troms and Finnmark with 225,000 inhabitants, have a relatively low prevalence of MS: 20.6 per 100,000 in 1973 and 31.5 in 1983. Also no person who is of pure Sami heritage (i.e., with both parents speaking Sami natively) has been found with the disease. Except for the introduction of magnetic resonance imaging as a diagnostic tool, there has been no significant change in the neurological service in the area during the past 20 years. Files of patients with the diagnosis of MS were reviewed, and questionnaires were sent to all patients alive on the prevalence day of 1 January 1993. The prevalence in 1993 was 73.0 per 100,000. The mean crude annual incidence rate was 3.5 per 100,000 during the period 1983-1992 compared with 3.0 during 1974-1982. In 1983 there were no pure Sami among the MS patients, but one had a Sami father. On 1 January 1993 there were three patients with both Sami parents and three with only one Sami parent, which is a rate that is still lower than would be expected if the prevalence of MS among the Sami were similar to that in the rest of the Norwegian population. The study shows that the incidence of MS in Troms and Finnmark has been increasing over the past 10 years, but is still lower than on the western coast and in the eastern part of Norway. The lowest incidence is found in Finnmark, where the Sami population is highest. During the past 10 years MS has also been diagnosed among the Sami population.

Cerebral computed tomography and electroencephalography compared with neuropsychological findings in systemic lupus erythematosus.

Central nervous system involvement was evaluated in 36 patients with systemic lupus erythematosus (SLE) using cerebral computed tomography (CT), electroencephalography (EEG), and a neuropsychological test battery. The purpose was to investigate whether brain dysfunction as assessed by comprehensive neuropsychological investigation is associated with findings of routine investigation methods such as CT and EEG which are available in most hospitals. Abnormal EEG was found in 19%, and CT revealed cerebral atrophy in 47% of SLE patients. Few neuropsychological functions were affected by the presence of abnormal EEG, cerebral atrophy, or infarcts. Significant associations were found only between cortical atrophy and impairment of tactile spatial problem-solving and motor dexterity, and between cortical infarcts and motor dexterity in the dominant hand. The value of conventional EEG in assessing cerebral SLE is negligible, except for identifying epileptic activity and focal pathology. Cerebral CT has little relevance in predicting brain dysfunction as established by neuropsychological assessment in SLE, except for detecting cortical atrophy and infarcts.

Neuropsychological dysfunction in systemic lupus erythematosus is not associated with changes in cerebral blood flow.

Cognitive dysfunction is found in a considerable proportion of patients with systemic lupus erythematosus (SLE). SPECT provides an estimate of regional cerebral blood flow (rCBF) which has been claimed to be sensitive to detect brain involvement in SLE. It is, however, uncertain if these perfusion defects are related to cognitive dysfunction. In the present study we investigated whether cerebral dysfunction assessed by neuropsychological measures was associated with changes in rCBE Fifty-two SLE patients were examined with a battery of neuropsychological tests and MRI of the brain. For each patient 99mTC-HMPAO-SPECT was performed with the visual cortex as reference, and a reduction in rCBF of > 15% was considered abnormal. Regional CBF was performed with an automated computer program quantitatively estimating blood perfusion in 16 symmetrical sectors of the brain. Several sectors of the brain showed varying areas of reduced rCBF with the temporal lobes most frequently involved. There were generally no associations between cognitive level of functioning and reduced rCBF. MRI demonstrated cerebral infarcts in 9 (17%) patients. In general rCBF was reduced in all sectors of the brain in patients with infarcts, although statistical significant difference in rCBF between patients with and without infarcts was only seen in the parietal lobe. Several neuropsychological functions were influenced by the presence of cerebral infarcts. There was no significant association between immunological measures and SPECT findings or neuropsychological measures. Neuropsychological dysfunction in SLE was associated with the presence of cerebral infarcts detected by MRI, but not by changes in rCBF. SPECT seems to add little if any information to that obtained by clinical examination, neuropsychological testing, and MRI. Since anticoagulation may prevent cerebral infarcts, such prophylactic intervention may be of importance in preventing cognitive deterioration.

Quantitative cerebral MR in rheumatoid arthritis.

PURPOSE: To determine the presence of hyperintense white matter lesions and atrophy reflecting cerebral vasculitis in rheumatoid arthritis. METHODS: Thirty-three patients with rheumatoid arthritis and 48 control subjects were examined with MR. Mean age was 45.1 years (range, 26 to 55 years) for the patients and 42.2 years (range, 25 to 55 years) in the control group. To determine atrophy we measured the area of corpus callosum, the cerebrum, and the cerebellum on midline sagittal sections. On transverse images, the ventricle-to-brain ratio, the bifrontal ratio, and the bicaudate ratio were selected as atrophy parameters. Area and signal intensity were measured for the biggest and the smallest lesions in both groups. RESULTS: Nine patients (27%) had hyperintense lesions compared with 15 (31%) of the control subjects. Mean numbers of hyperintense lesions were 1.3 in patients and 2.1 in control subjects. Mean area of the largest lesion in each patient was 27.4 mm2 for the patients and 29.8 mm2 in the control group. In patients with long disease duration (> 15 years) the mean ventricle-to-brain ratio was 0.09 compared with 0.08 in the control subjects. The midsagittal area of the cerebellum was 1349.8 mm2 in the patients with long disease duration and 1573.3 mm2 in the control group. No difference in number of hyperintense white matter lesions was detected between patients with long disease duration and the control subjects. Comparing the total group of patients with the control subjects, no significant differences in atrophy parameters or hyperintense white matter lesions were found. Also, there were no significant differences in relative signal intensity of the hyperintense lesions and corpus callosum between the two groups. We were not able to detect differences between treated versus untreated patients. CONCLUSION: This study indicates a tendency of more cerebral and cerebellar atrophy in patients with severe rheumatoid arthritis. The number and size of the white matter lesions were not significantly different in the two groups and do not support a higher frequency of even clinically silent infarcts caused by vasculitis in the patients with rheumatoid arthritis compared with control subjects.

Quality of life in rheumatoid arthritis: a case-control study in patients living in northern Norway.

OBJECTIVE: To study quality of life parameters in patients with rheumatoid arthritis and the possible association of these parameters with disease activity. METHODS: Fifty-two women with rheumatoid arthritis and 52 controls completed two self reporting psychiatric screening tests: the General Health Questionnaire (GHQ - 30) and the Cantril Ladder scale. The number of psychiatric cases detected was not significantly higher for either group using the GHQ score S+ as the criterion. RESULTS: Comparing the GHQ scores, patients showed a higher score compared with the controls (p = 0.02). The patients scored significantly higher on feelings of incompetance (p = 0.004), but not on the other subgroups of psychiatric factors. The patients reported lower life satisfaction on the Cantril self anchoring ladder (p = 0.0001). The functional capacity score was positively associated with the GHQ score. No association was detected between disease duration or the other disease activity parameters and either the GHQ score or the life satisfaction score. CONCLUSION: This inconsistant relationship between clinical parameters and quality of life scores may be due to the fact that RA patients suffer from a chronic disease, or it may reflect an impaired psychosocial status in the patients. This study demonstrates that the increased psychological disturbances in women with RA is mainly explained by feelings of incompetance.

The function of sensory nerve fibers in lumbar radiculopathy. Use of quantitative sensory testing in the exploration of different populations of nerve fibers and dermatomes.

STUDY DESIGN: The function of sensory nerve fibers in patients with lumbar radiculopathy and in control individuals was evaluated using quantitative sensory testing. OBJECTIVES: To investigate the effect of lumbar nerve root compression on different populations of nerve fibers and to explore the function of sensory nerve fibers in neighboring nerve roots not involved in the mechanical compression. BACKGROUND DATA: Results from experimental and clinical studies indicate that chronic compression of lumbar nerve roots affects the large myelinated nerve fibers. The majority of nerve fibers involved in the sensation of pain, however, are small afferent nerve fibers. It is therefore of interest to study the effect of compression on large and small sensory afferent channels. Several authors have elucidated the biochemical interaction between disc tissue and nerve roots. Chemical substances in the epidural space can reach the nerve fibers in nerve roots at the same or neighboring lumbar segments. In this way, fibers not involved in the mechanical compression may be affected. METHODS: The small nerve fibers were studied using tests for thermal thresholds (thermotest), and the large myelinated fibers were studied by vibrametry. Forty-two patients were investigated in the symptomatic and the asymptomatic leg, and the results were compared with those of 21 healthy individuals. RESULTS: The thresholds of cold, warmth, and vibration were significantly increased in the dermatome of the compressed nerve root, indicating that large and small sensory nerve fibers were affected. Further, the thresholds were significantly increased in the neighboring dermatomes in the symptomatic and the asymptomatic leg. CONCLUSION: Large and small sensory afferent nerve fibers are affected in lumbar radiculopathy. The increase in sensation thresholds in the ipsilateral neighboring dermatome and in the dermatomes in the asymptomatic leg indicates that adjacent nerve roots are involved in the pathophysiology of sciatica in patients with lumbar disc herniation.