Electrodiagnostic methods to verify Guillain-Barré syndrome subtypes in Istanbul: A prospective multicenter study.

BACKGROUND AND AIMS: This study aimed to identify the clinical characteristics and electrodiagnostic subtypes of Guillain-Barré syndrome (GBS) in Istanbul. METHODS: Patients with GBS were prospectively recruited between April 2019 and March 2022 and two electrodiagnostic examinations were performed on each patient. The criteria of Ho et al., Hadden et al., Rajabally et al., and Uncini et al. were compared for the differentiation of demyelinating and axonal subtypes, and their relations with anti-ganglioside antibodies were analyzed. RESULTS: One hundred seventy-seven patients were included, 69 before the coronavirus disease 2019 pandemic (April 2019-February 2020) and 108 during the pandemic (March 2020-March 2022), without substantial changes in monthly frequencies. As compared with the criteria of Uncini et al., demyelinating GBS subtype diagnosis was more frequent according to the Ho et al. and Hadden et al. criteria (95/162, 58.6% vs. 110/174, 63.2% and 121/174, 69.5%, respectively), and less frequent according to Rajabally et al.'s criteria (76/174, 43.7%). Fourteen patients' diagnoses made using Rajabally et al.'s criteria were shifted to the other subtype with the second electrodiagnostic examination. Of the 106 analyzed patients, 22 had immunoglobulin G anti-ganglioside antibodies (14 with the axonal subtype). They had less frequent sensory symptoms (54.5% vs. 83.1%, p = 0.009), a more frequent history of previous gastroenteritis (54.5% vs. 22.9%, p = 0.007), and a more severe disease as compared with those without antibodies. INTERPRETATION: Serial electrodiagnostic examinations are more helpful for accurate subtype diagnosis of GBS because of the dynamic pathophysiology of the disease. We observed no significant increase in GBS frequency during the pandemic in this metropolis.

Neuropathic Pain Frequency in Neurology Outpatients: A Multicenter Study.

INTRODUCTION: Neuropathic pain is common, but the frequency of misdiagnosis and irrational treatment is high. The aim of this study is to evaluate the rate of neuropathic pain in neurology outpatient clinics by using valid and reliable scales and review the treatments of patients. METHODS: The study was conducted for 3 months in eleven tertiary health care facilities. All outpatients were asked about neuropathic pain symptoms. Patients with previous neuropathic pain diagnosis or who have neuropathic pain symptoms were included and asked to fill painDETECT and douleur neuropathic en 4 questions (DN4) questionnaire. Patients whose DN4 score is higher than 3 and/or painDETECT score higher than 13 and/or who are on drugs for neuropathic pain were considered patients with neuropathic pain. The frequency of neuropathic pain was calculated and the treatments of patients with neuropathic pain were recorded. RESULTS: Neuropathic pain frequency was 2.7% (95% CI: 1.5-4.9). The most common cause was diabetic neuropathy. According to painDETECT, the mean overall pain intensity was 5.7±2.4, being lower among patients receiving treatment. Pharmacological neuropathic pain treatment was used by 72.8% of patients and the most common drug was pregabalin. However, 70% of those receiving gabapentinoids were using ineffective doses. Besides, 4.6% of the patients were on medications which are not listed in neuropathic pain treatment guidelines. CONCLUSION: In our cohort, the neuropathic pain severity was moderate and the frequency was lower than the literature. Although there are many guidelines, high proportion of patients were being treated by ineffective dosages or irrational treatments.

A database for screening and registering late onset Pompe disease in Turkey.

The aim of this study was to search for the frequency of late onset Pompe disease (LOPD) among patients who had a myopathy with unknown diagnosis registered in the pre-diagnostic part of a novel registry for LOPD within a collaborative study of neurologists working throughout Turkey. Included in the study were 350 patients older than 18 years who have a myopathic syndrome without a proven diagnosis by serum creatine kinase (CK) levels, electrodiagnostic studies, and/or muscle pathology, and/or genetic tests for myopathies other than LOPD. Acid alpha glucosidase (GAA) in dried blood spot was measured in each patient at two different university laboratories. LOPD was confirmed by mutation analysis in patients with decreased GAA levels from either both or one of the laboratories. Pre-diagnostic data, recorded by 45 investigators from 32 centers on 350 patients revealed low GAA levels in a total of 21 patients; from both laboratories in 6 and from either one of the laboratories in 15. Among them, genetic testing proved LOPD in 3 of 6 patients and 1 of 15 patients with decreased GAA levels from both or one of the laboratories respectively. Registry was transferred to Turkish Neurological Association after completion of the study for possible future use and development. Our collaborative study enabled collection of a considerable amount of data on the registry in a short time. GAA levels by dried blood spot even from two different laboratories in the same patient may not prove LOPD. LOPD seemed to be rarer in Turkey than in Europe.

Cutaneous silent period in myofascial pain syndrome.

INTRODUCTION: An increased response to painful stimuli without spontaneous pain suggests a role of central hyperexcitability of pain pathways in the pathogenesis of myofascial pain syndrome (MPS). In this study we aimed to test the hypothesis that spinal pain pathways are affected in MPS. We used cutaneous silent period (CSP) parameters to demonstrate the hyperexcitability of spinal pain pathways in MPS. METHODS: Twenty-nine patients diagnosed with MPS and 30 healthy volunteers were included in the study. The CSP recordings were performed in the right upper and left lower extremities. RESULTS: In both upper and lower extremities, patients had prolonged CSP latencies (P = 0.034 and P = 0.049 respectively) and shortened CSP durations (P = 0.009 and P = 0.008, respectively). DISCUSSION: Delayed and shortened CSP in MPS patients implies dysfunction in the inhibitory mechanism of the spinal/supraspinal pain pathways, suggesting central sensitization in the pathogenesis of MPS and supporting our research hypothesis. Muscle Nerve 57: E24-E28, 2018.

Motor-Unit Number Estimation Is Sensitive in Detecting Motor Nerve Involvement in Patients with Carpal Tunnel Syndrome.

BACKGROUND AND PURPOSE: We compared the motor-unit number estimation (MUNE) findings in patients who presented with signs and/or findings associated with carpal tunnel syndrome (CTS) and healthy controls, with the aim of determining if motor-unit loss occurs during the clinically silent period and if there is a correlation between clinical and MUNE findings in CTS patients. METHODS: The study investigated 60 hands of 35 patients with clinical CTS and 60 hands of 34 healthy controls. Routine median and ulnar nerve conduction studies and MUNE analysis according to the multipoint stimulation method were performed. RESULTS: The most common electrophysiological abnormality was reduced conduction velocity in the median sensory nerve (100% of the hands). The MUNE value was significantly lower for the patient group than for the control group (p=0.0001). ROC analysis showed that a MUNE value of 121 was the optimal cutoff for differentiating between patients and controls, with a sensitivity of 63.3% and a specificity of 68.3%. MUNE values were lower in patients with complaints of numbness, pain, and weakness in the median nerve territory (p<0.05, for all comparisons), and lower in patients with hypoesthesia than in patients with normal neurological findings (p=0.023). CONCLUSIONS: The MUNE technique is sensitive in detecting motor nerve involvement in CTS patients who present with sensorial findings, and it may be useful in detecting the loss of motor units during the early stages of CTS. Larger-scale prospective clinical trials assessing the effect of early intervention on the outcome of these patients would help in confirming the possible benefit of detecting subclinical motor-unit loss in CTS.

Assessment of symptomatic diabetic patients with normal nerve conduction studies: utility of cutaneous silent periods and autonomic tests.

Established electrophysiological methods have limited clinical utility in the diagnosis of small-fiber neuropathy (SFN). In this study, diabetic patients with clinically diagnosed SFN were evaluated with autonomic tests and cutaneous silent periods (CSPs). Thirty-one diabetic patients with clinically suspected SFN and normal nerve conduction studies were compared with 30 controls. In the upper extremities (UE), the CSP parameters did not differ statistically between the patient and control groups, whereas, in the lower extremities (LE), patients had prolonged CSP latencies (P = 0.018) and shortened CSP durations (P < 0.001). The sensitivity of the CSP duration was 32.6%, and the specificity was 96.7%. The expiration-to-inspiration ratios and amplitudes of the sympathetic skin responses in the lower extremities were also reduced. Our findings indicate that the diagnostic utility of CSPs was higher than that of the autonomic tests to support the clinically suspected diagnosis of SFN.

Paraneoplastic pandysautonomia as a manifestation of non-small cell lung cancer.

Pandysautonomia is a severe and rare clinical condition characterized by widespread sympathetic and parasympathetic dysfunction. Consideration of whether symptoms and presentation are acute, subacute, or chronic is often helpful in establishing a differential diagnosis. The underlying mechanisms leading to pure pandysautonomia are unclear; however, there is some evidence suggestive of an immune-mediated pathogenesis. Herein, we report a case with pandysautonomia as a paraneoplastic manifestation of non-small cell lung cancer that had an excellent response to symptomatic and supportive treatments, as well as IVIG therapy.

Medial plantar and dorsal sural nerve conduction studies increase the sensitivity in the detection of neuropathy in diabetic patients.

OBJECTIVE: Clinical utility of nerve conduction studies (NCS) of the medial plantar and dorsal sural nerves in the early detection of polyneuropathy have already been shown separately. However, at present, there is no data about the combined assessment of these two nerves in distal sensory neuropathy. In the present study, we aimed to evaluate the medial plantar and dorsal sural NCS in a group of diabetic patients with distal sensory neuropathy (DSN) and in healthy controls. METHODS: Thirty healthy and 30 diabetic adult patients were included. In all subjects, peripheral motor and sensory NCS were performed bilaterally with surface electrodes on the lower limbs including medial plantar and dorsal sural nerves. In addition, motor and sensory nerves were studied unilaterally on the upper limb. RESULTS: In all patients, nerve action potential (NAP) amplitudes of sural and superficial peroneal nerves were within normal ranges, but in the patient group mean value was significantly lower than in the controls. Among clinically defined 30 DSN patients, medial plantar NAP amplitude was abnormal in 18 (60%) and dorsal sural nerve amplitude was abnormal in 13 (40%) of the patients bilaterally. Additionally, the onset NCV of the dorsal sural nerve was significantly slower in patients than controls (P=0.038). Evaluation of both of these nerves increased the sensitivity up to 70% in the detection of neuropathy. CONCLUSIONS: Bilateral NCS assessment of both of the medial plantar and dorsal sural nerves together increases the rate of diagnosis of diabetic distal sensory neuropathy compared to assessment of either of these nerves. SIGNIFICANCE: Assessment of medial plantar in addition to dorsal sural NCS together increases the sensitivity in the detection of neuropathy and allows earlier diagnosis, especially when routine NCS are normal.