Volumetric assessment of ulnar nerves in cubital tunnel syndrome with 3D modeling of the MRI and its relationship with electrodiagnostic findings.

BACKGROUND: Thickened nerve cross-sectional areas (CSA) have been investigated in compressive neuropathy, but the longitudinal extent of nerve swelling has yet to be evaluated. We did a volumetric assessment of the ulnar nerve in cubital tunnel syndrome (CuTS) with three-dimensional (3D) magnetic resonance imaging (MRI) modeling and investigated this relationship with clinical and electrodiagnostic parameters. METHODS: We compared 40 CuTS patient elbow MRIs to 46 patient elbow MRIs with lateral elbow epicondylitis as controls. The ulnar nerve was modeled with Mimics software and was assessed qualitatively and quantitatively. The CSA and ulnar nerve volumes were recorded, and the area under the receiver operating characteristic (ROC) curve was calculated for diagnostic performance. We analyzed clinical and electrodiagnostic parameters to investigate their relationship with the 3D ulnar nerve parameters. RESULTS: For the diagnosis of CuTS, the area under the curve value was 0.915 for the largest CSA and 0.910 for the volume in the ROC curve. The optimal cut-off was 14.53 mm2 and 529 mm3 respectively. When electrodiagnostic parameters were investigated, the 3D ulnar nerve volume was significantly inversely associated with motor conduction velocity, although there was no association between the largest CSA and any of the electrodiagnostic parameters. CONCLUSIONS: The 3D ulnar nerve volume, which is an integration or multilevel measurement of CSAs, showed diagnostic usefulness similar to CSA, but it correlated better with conduction velocity, indicating demyelination or early-to-moderate nerve damage in CuTS.

Electrodiagnostic assessment of the autonomic nervous system: A consensus statement endorsed by the American Autonomic Society, American Academy of Neurology, and the International Federation of Clinical Neurophysiology.

Evaluation of disorders of the autonomic nervous system is both an art and a science, calling upon the physician's most astute clinical skills as well as knowledge of autonomic neurology and physiology. Over the last three decades, the development of noninvasive clinical tests that assess the function of autonomic nerves, the validation and standardization of these tests, and the growth of a large body of literature characterizing test results in patients with autonomic disorders have equipped clinical practice further with a valuable set of objective tools to assist diagnosis and prognosis. This review, based on current evidence, outlines an international expert consensus set of recommendations to guide clinical electrodiagnostic autonomic testing. Grading and localization of autonomic deficits incorporates scores from sympathetic cardiovascular adrenergic, parasympathetic cardiovagal, and sudomotor testing, as no single test alone is sufficient to diagnose the degree or distribution of autonomic failure. The composite autonomic severity score (CASS) is a useful score of autonomic failure that is normalized for age and gender. Valid indications for autonomic testing include generalized autonomic failure, regional or selective system syndromes of autonomic impairment, peripheral autonomic neuropathy and ganglionopathy, small fiber neuropathy, orthostatic hypotension, orthostatic intolerance, syncope, neurodegenerative disorders, autonomic hyperactivity, and anhidrosis.

Evaluation of persons with suspected lumbosacral and cervical radiculopathy: Electrodiagnostic assessment and implications for treatment and outcomes (Part I).

Persons with back, neck, and limb symptoms constitute a major referral population to specialists in electrodiagnostic (EDX) medicine. The evaluation of these patients involves consideration of both the common and less common disorders. The EDX examination with needle electromyography (EMG) is the most important means of testing for radiculopathy. This test has modest sensitivity but high specificity and well complements imaging of the spine. Needle EMG in combination with nerve conduction testing is valuable in excluding entrapment neuropathies and polyneuropathy-conditions that frequently mimic radicular symptoms. In this first of a two-part review, the optimal EDX evaluation of persons with suspected radiculopathy is presented. In part two, the implications of EDX findings for diagnosis and clinical management of persons with radiculopathy are reviewed.

Evaluation of persons with suspected lumbosacral and cervical radiculopathy: Electrodiagnostic assessment and implications for treatment and outcomes (Part II).

The electrodiagnostic (EDX) examination with needle electromyography (EMG) is the most important means of testing for radiculopathy. This test has modest sensitivity but high specificity and complements imaging of the spine. In this second of a two-part review, the implications of electrodiagnostic findings for diagnosis and clinical management of persons with radiculopathy are reviewed. An EMG confirmed lumbosacral radiculopathy is associated with better clinical outcomes for persons undergoing aggressive conservative management. A positive EMG test portends a better clinical response to epidural corticosteroid injections. If a person undergoes spine surgery, a positive pre-operative EMG for radiculopathy is also associated with better outcomes.

Functional muscle balance assessment in multiple sclerosis.

BACKGROUND: Chronic demyelinisation in multiple sclerosis (MS) involves changes in the muscle structure and development of motor disorders. OBJECTIVE: The aim of this research is to assess the muscle balance of thigh muscle in MS using a noninvasive method, to have information about the muscle status prior to the rehabilitation and to prevent muscle damage. METHODS: The studied group consisted of 20 patients: 9 men and 11 women, with a mean age of 42 years. The patients were diagnosed with MS in different stages. The clinical evaluation included clinical examination, neurological examination, functional evaluation by using the Hamilton score, the activity daily living (ADL) scale and the Kurtze (EDSS) scale. For the muscle assessment we used tensiomyography (TMG), an evaluation method for the functional potential of the muscle, depending on the muscle composition. The TMG parameters are displacement (Dm), contraction time (Tc) and sustain time (Ts) for biceps femoris (mBF) and rectus femoris (mRF). RESULTS: The value of Dm shows low values for both studied muscle groups, but closer to the normal value for mBF. The average normal Tc values for mBF are 30.25 ± 3.5 ms and 32.83 ± 4.5 for mRF. The values are low values for mRF and high for mBF. The normal values of Ts are not standard values and can be compared healthy individuals' values. These parameters could monitor the evolution and in our research have lower values for mRF. In the thigh, there was a significant difference in the Dm values, with higher values in mBF and also with higher values in the right lower limb. Analyzing the Ts results, we noticed a difference between the two muscle groups with a significant reduction in mRF, showing the inability to achieve anterior-posterior symmetry and the tendency to develop type I fibers at mBF level. CONCLUSIONS: Our study showed the presence of a structural and functional asymmetry explained by the tendency of increasing the tonus at mRF level in order to compensate the knee stability. We noticed a decrease in Tc value at the mRF level, but close to the value of the two lower limbs. TMG analysis revealed the asymmetry of the muscle composition at the level of the antagonist muscle groups of the thigh, with an increase in the percentage of type II fibers in the previous group, which became hyperton, and a decrease in the percentage of type I fibers in the posterior group.

Electrophysiological Assessment and Classification of Motor Pathway Function in Patients With Spinal Dural Arteriovenous Fistula.

PURPOSE: The diagnosis of spinal dural arteriovenous fistula (SDAVF) is difficult and often delayed because clinical features are often nonspecific. We assessed the motor function electrophysiologically in patients with SDAVF. METHODS: Motor-evoked potentials after transcranial magnetic stimulation and compound muscle action potentials and F-waves after electrical stimulation in the ulnar and tibial nerves were measured from the abductor hallucis (AH) muscles in 14 patients with SDAVF (SDAVF group), 12 patients with compressive thoracic myelopathy (CTM group), and 16 normal subjects (control group). The peripheral conduction time determined from abductor hallucis muscles (PCT-AH) and the central motor conduction time determined from abductor hallucis muscles (CMCT-AH) were calculated. According to the neurological findings, patients in the SDAVF group were classified to upper motor neuron (UMN) sign and lower motor neuron (LMN) sign categories. RESULTS: CMCT-AH in the SDAVF and CMT groups were significantly longer than those in the control group. PCT-AH in the SDAVF group was significantly longer than that in the control and CMT groups. Twelve patients in the SDAVF group showed abnormal CMCT-AH and/or PCT-AH. Abnormal CMCT-AH and PCT-AH were detected in five cases that exhibited UMN sign and/or LMN sign. Three cases with abnormal CMCT-AH and normal PCT-AH exhibited UMN sign. LMN sign without UMN sign was observed in four cases with abnormal PCT-AH and normal CMCT-AH. CONCLUSIONS: Our study revealed abnormalities in the corticospinal tract and/or lower motor neurons, and classified the patients with SDAVF into three types: the UMN type, LMN type, and mixed type.

Novel Modeling of Somatosensory Evoked Potentials for the Assessment of Spinal Cord Injury.

OBJECTIVE: Previous work has shown that differences in the somatosensory evoked potential (SEP) signals between a normal spinal pathway and spinal pathway affected by spinal cord injury (SCI) provide a means to study the degree of injury. This paper proposes a novel quantitative SCI assessment method using time-domain SEP signals. METHODS: A pruned and unstructured fit between SEP signals from a normal spinal pathway and a spinal pathway affected by SCI is developed using methods inspired by recent results in sparse reconstruction theory. The coefficients from the resulting fit are used to develop a quantitative assessment of SCI that is tested on actual SEP signals collected from rodents that have been subjected to partial and complete spinal cord transection. RESULTS: The proposed method provides a rich parametric measure that integrates SEP amplitude, time latency, and morphology, while exhibiting a high degree of correlation with existing subjective and quantitative SCI assessment methods. CONCLUSION: The proposed SCI encapsulates a model of the injury to quantify SCI. SIGNIFICANCE: The proposed SCI quantification method may be used to complement existing SCI assessment methods.

Effective Glottal Instant Detection and Electroglottographic Parameter Extraction for Automated Voice Pathology Assessment.

Accurate determination of glottal instants and electroglottographic (EGG) parameters is most important in voice pathology analysis including multiple voice disorders: neurological, functional, and laryngeal diseases. In this paper, we present a new effective method for reliable detection of glottal instants and EGG parameters from an EGG signal composed of voiced and nonvoice segments. In the first stage, we present an adaptive variational mode decomposition based algorithm for suppressing low-frequency artifacts and additive high-frequency noises. Based upon mode center frequency criterion, the proposed method first constructs a candidate EGG feature signal for determination of glottal closure and opening instants. In the second stage, the candidate glottal instants are determined by detecting the positive and negative zerocrossings in normalized candidate EGG feature signal, respectively. Finally, an autocorrelation features based postprocessing algorithm is presented to reject nonglottal instants from the nonspeech production segments. The accuracy and robustness of the method is tested using noise-free and noisy EGG signals. Evaluation results show that the proposed method achieves an average overall accuracy of 95.06%, identification rate of 95.34%, missed rate of 3.60%, and false alarm rate of 0.06% with average absolute identification error of 0.71 ± 0.66 ms for an SNR of 15 dB. Results demonstrate that the proposed method significantly outperforms the other existing methods under both noise-free and noisy EGG signals.

The Clinical Diagnostic Utility of Electrophysiological Techniques in Assessment of Patients With Disorders of Consciousness Following Acquired Brain Injury: A Systematic Review.

OBJECTIVE: To investigate the diagnostic utility of electrophysiological recordings during active cognitive tasks in detecting residual cognitive capacities in patients with disorders of consciousness (DoC) after severe acquired brain injury. DESIGN: Systematic review of empirical research in MEDLINE, Embase, PsycINFO, and Cochrane from January 2002 to March 2016. MAIN MEASURES: Data extracted included sample size, type of electrophysiological technique and task design, rate of cognitive responders, false negatives and positives, and excluded subjects from the study analysis. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used for quality appraisal of the retrieved literature. RESULTS: Twenty-four studies examining electrophysiological signs of command-following in patients with DoC were identified. Sensitivity rates in healthy controls demonstrated variable accuracy across the studies, ranging from 71% to 100%. In patients with DoC, specificity and sensitivity rates varied in the included studies, ranging from 0% to 100%. Pronounced heterogeneity was found between studies regarding methodological approaches, task design, and procedures of analysis, rendering comparison between studies challenging. CONCLUSION: We are still far from establishing precise recommendations for standardized electrophysiological diagnostic procedures in DoC, but electrophysiological methods may add supplemental diagnostic information of covert cognition in some patients with DoC.

Assessment of bolus transit with intraluminal impedance measurement in patients with esophageal motility disorders.

BACKGROUND: The clinical management of patients with non-obstructive dysphagia is notoriously difficult. Esophageal impedance measurement can be used to measure esophageal bolus transit without the use of radiation exposure to patients. However, validation of measurement of bolus transit with impedance monitoring has only been performed in healthy subjects with normal motility and not in patients with dysphagia and esophageal motility disorders. The aim was, therefore, to investigate the relationship between transit of swallowed liquid boluses in healthy controls and in patients with dysphagia. METHODS: Twenty healthy volunteers and 20 patients with dysphagia underwent concurrent impedance measurement and videofluoroscopy. Each subject swallowed five liquid barium boluses. The ability of detecting complete or incomplete bolus transit by means of impedance measurement was assessed, using radiographic bolus transit as the gold standard. KEY RESULTS: Impedance monitoring recognized stasis and transit in 80.5% of the events correctly, with 83.9% of bolus transit being recognized and 77.2% of stasis being recognized correctly. In controls 79.8% of all swallows were scored correctly, whereas in patients 81.3% of all swallows were scored correctly. Depending on the contractility pattern, between 77.0% and 94.3% of the swallows were scored correctly. CONCLUSIONS & INFERENCES: Impedance measurement can be used to assess bolus clearance patterns in healthy subjects, but can also be used to reliably assess bolus transit in patients with dysphagia and motility disorders.

Assessment of Peripheral Neuropathy Using Measurement of the Current Perception Threshold with the Neurometer® in patients with type 1 diabetes mellitus.

OBJECTIVE: The aim of this study is to evaluate the role of current perception threshold (CPT) measurement in peripheral neuropathy in type 1 diabetic patients by using the Neurometer(®), a nerve measuring instrument. METHODS: 52 patients with type 1 diabetes mellitus with a disease duration of less than five years and normal neuropathy symptom score (NSS), neuropathy disability score (NDS) and sensory nerve conduction velocity (SCV), and 40 healthy controls were enrolled in this study. Measurement of CPT using the Neurometer(®) at 2000, 250 and 5 Hz assesses function in the bilateral median nerve and sural nerve in all studied cases. We also evaluated the glycated hemoglobin, microalbuminuria, urinary albumin/creatinine ratio and other metabolism indexes of all patients. RESULTS: The CPT of the bilateral median nerve and sural nerve was significantly lower in diabetic patients (P<0.01). Moreover, the number of median nerve injuries in the diabetic group (left side 8/52, right side 8/52) is significantly different from the number of its ipsilateral sural nerve injuries (left side 28/52, right side 22/52) (left side P<0.01, right side P<0.01). By comparing those with DPN and those without DPN in the diabetic group, DPN groups had significantly higher glycated hemoglobin (t=2.518, P<0.05). Using binary logistic regression, high glycated hemoglobin was identified to be an independent risk factor of DPN incidence (OR (95% CI): 1.317 (1.013 -1.712), P<0.05). CONCLUSION: These data suggest that CPT is useful in early detection of peripheral neuropathy in patients with type 1 diabetes mellitus. Patients with diabetic peripheral neuropathy, the lower limb nerve is more vulnerable than the upper limb nerve. In addition, patients with DPN had higher glycated hemoglobin which is an independent risk factor of DPN.

Investigating the feasibility of EVestG assessment for screening concussion.

Electrovestibulography (EVestG™) is a new technology that objectively measures the vestibular response. It has the potential to objectively, quickly and cost-effectively screen concussion. EVestG signals are recorded painlessly and non-invasively from the external ear in response to vestibular stimuli, and consist of brainstem and peripheral sensory oto-acoustic signals modulated by the cortical responses. In this study, we investigated the relationship between characteristic features of the extracted field potentials (FPs) of EVestG signals in people with side-impact concussion in comparison with those of control participants. 10 side-impact concussed individuals (4 Right and 6 left side-impact) and 10 age-and-gender-matched controls were tested by EVestG. The participants also completed comprehensive neuropsychological assessments. Characteristic features were extracted from the FPs during side tilt, and linear discriminant analysis (LDA) classification was applied to the extracted features using a leave-one-out routine. The results show the difference between the left and right FP area was significantly (P<0.05) different. The LDA classification resulted a sensitivity of 85% and specificity of 69% for separating concussed individuals from controls. EVestG appears to have diagnostic potential in diagnosing side impact concussion.

Comparison of ultrasound and electrodiagnostic testing for diagnosis of carpal tunnel syndrome: study using a validated clinical tool as the reference standard.

BACKGROUND: Ultrasound examination is both accurate and cost-effective for the confirmation of a clinical diagnosis of carpal tunnel syndrome. Previous studies have shown electrodiagnostic testing and ultrasound to be similar with regard to sensitivity and specificity. The purpose of this study was to compare the sensitivity and specificity of ultrasound and electrodiagnostic testing by using a validated clinical diagnostic tool as the reference standard. METHODS: All consecutive patients referred to an upper-extremity practice for electrodiagnostic testing for any reason over a three-month period were recruited to participate in this study. All patients were evaluated with the use of the Carpal Tunnel Syndrome 6 (CTS-6) clinical diagnostic tool, and a score of ≥12 was considered positive for carpal tunnel syndrome. A positive finding on ultrasound was considered to be a cross-sectional area of the median nerve, measured just proximal to the level of the pisiform, of ≥10 mm(2). A positive finding on electrodiagnostic testing was a distal motor latency of ≥4.2 ms and/or a distal sensory latency of ≥3.2 ms. Sensitivity, specificity, and accuracy were calculated for ultrasound and electrodiagnostic testing with use of the CTS-6 as the reference standard. RESULTS: With use of the CTS-6 as the reference standard, ultrasound had a sensitivity of 89% and a specificity of 90% in our series of eighty-five patients. Electrodiagnostic testing had a sensitivity of 89% and a specificity of 80%. The positive predictive value of ultrasound was 94% compared with 89% for electrodiagnostic testing. The negative predictive value of ultrasound was 82% compared with 80% for electrodiagnostic testing. Ultrasound was accurate in seventy-six (89%) of the eighty-five cases whereas electrodiagnostic testing was accurate in seventy-three (86%) of the eighty-five cases (p = 0.5). CONCLUSIONS: While ultrasound will not replace electrodiagnostic testing in complicated or unclear cases, in a select group of patients with a positive CTS-6, ultrasound can be used to confirm the diagnosis of carpal tunnel syndrome with better specificity and equal sensitivity as compared with those of electrodiagnostic testing. LEVEL OF EVIDENCE: Diagnostic Level I. See Instructions for Authors for a complete description of levels of evidence.

Objective assessment of C-fiber function by electrically induced axon reflex flare in patients with axonal and demyelinating polyneuropathy.

INTRODUCTION: A simple test to evaluate the peripheral C-fiber function is the measurement of axon reflex flare area. In this study, we compared the flare area in healthy subjects and in two groups of patients with predominantly axonal or demyelinating polyneuropathy. MATERIALS AND METHODS: We examined 42 control subjects and 33 patients. The flare responses were elicited by the application of transcutaneous electrical stimulation and recorded by laser Doppler imaging. RESULTS: There was a significant reduction of electrically induced flare area in both groups of neuropathy patients (P < 0.001; analysis of covariance). Interestingly, patients with an axonal neuropathy had a significantly stronger reduction of flare size as compared to patients with demyelinating neuropathy (P = 0.03). CONCLUSIONS: The evaluation of the axon flare response in the arm can be used as a screening test of impaired C-fiber function in polyneuropathy patients with the advantages of simplicity of the procedure and time economy.

Nerve excitability assessment in chemotherapy-induced neurotoxicity.

Chemotherapy-induced neurotoxicity is a serious consequence of cancer treatment, which occurs with some of the most commonly used chemotherapies(1,2). Chemotherapy-induced peripheral neuropathy produces symptoms of numbness and paraesthesia in the limbs and may progress to difficulties with fine motor skills and walking, leading to functional impairment. In addition to producing troubling symptoms, chemotherapy-induced neuropathy may limit treatment success leading to dose reduction or early cessation of treatment. Neuropathic symptoms may persist long-term, leaving permanent nerve damage in patients with an otherwise good prognosis(3). As chemotherapy is utilised more often as a preventative measure, and survival rates increase, the importance of long-lasting and significant neurotoxicity will increase. There are no established neuroprotective or treatment options and a lack of sensitive assessment methods. Appropriate assessment of neurotoxicity will be critical as a prognostic factor and as suitable endpoints for future trials of neuroprotective agents. Current methods to assess the severity of chemotherapy-induced neuropathy utilise clinician-based grading scales which have been demonstrated to lack sensitivity to change and inter-observer objectivity(4). Conventional nerve conduction studies provide information about compound action potential amplitude and conduction velocity, which are relatively non-specific measures and do not provide insight into ion channel function or resting membrane potential. Accordingly, prior studies have demonstrated that conventional nerve conduction studies are not sensitive to early change in chemotherapy-induced neurotoxicity(4-6). In comparison, nerve excitability studies utilize threshold tracking techniques which have been developed to enable assessment of ion channels, pumps and exchangers in vivo in large myelinated human axons(7-9). Nerve excitability techniques have been established as a tool to examine the development and severity of chemotherapy-induced neurotoxicity(10-13). Comprising a number of excitability parameters, nerve excitability studies can be used to assess acute neurotoxicity arising immediately following infusion and the development of chronic, cumulative neurotoxicity. Nerve excitability techniques are feasible in the clinical setting, with each test requiring only 5 -10 minutes to complete. Nerve excitability equipment is readily commercially available, and a portable system has been devised so that patients can be tested in situ in the infusion centre setting. In addition, these techniques can be adapted for use in multiple chemotherapies. In patients treated with the chemotherapy oxaliplatin, primarily utilised for colorectal cancer, nerve excitability techniques provide a method to identify patients at-risk for neurotoxicity prior to the onset of chronic neuropathy. Nerve excitability studies have revealed the development of an acute Na(+) channelopathy in motor and sensory axons(10-13). Importantly, patients who demonstrated changes in excitability in early treatment were subsequently more likely to develop moderate to severe neurotoxicity(11). However, across treatment, striking longitudinal changes were identified only in sensory axons which were able to predict clinical neurological outcome in 80% of patients(10). These changes demonstrated a different pattern to those seen acutely following oxaliplatin infusion, and most likely reflect the development of significant axonal damage and membrane potential change in sensory nerves which develops longitudinally during oxaliplatin treatment(10). Significant abnormalities developed during early treatment, prior to any reduction in conventional measures of nerve function, suggesting that excitability parameters may provide a sensitive biomarker.

Electrodiagnostic assessment of the brachial plexus.

The brachial plexus is one of the largest and most complex structures of the peripheral nervous system and, as such, cannot be studied by a single nerve conduction study (NCS) or muscle sampled by needle electrode examination (NEE). Typically, the screening sensory NCS is used and expanded to identify the region of involvement, the motor NCS is applied to determine the severity of the process, and the NEE is used to further characterize the lesion. Our approach to the electrodiagnostic assessment of the brachial plexus is the focus of this article; 3 electrodiagnostic cases with discussion follow this article.

Clinic-based nerve conduction studies reduce time to surgery and are cost effective: a comparison with formal electrophysiological testing.

INTRODUCTION: Carpal tunnel syndrome is the most common compression neuropathy affecting the upper limb. Clinical diagnosis is not always clear and electrophysiological testing can be indicated when considering a patient for decompression surgery. The downside of electrophysiological testing is cost and increased time to surgery. Newer methods of performing nerve conduction studies in clinic have become available. MATERIALS AND METHODS: We investigated the use of a clinic-based, handheld, non-invasive electrophysiological device (NC-stat®) in 71 patients with suspected carpal tunnel syndrome presenting to our hand clinic in a district general hospital. We compared this to a similar cohort of 71 age-matched patients also presenting to our unit in whom formal nerve conduction studies were performed at a local neurophysiology unit. Our outcome measures were time from presentation to carpal tunnel decompression, the cost of each pathway and the practicalities of using the device in a busy hand unit. RESULTS AND CONCLUSIONS: The NC-stat® proved to be a successful device when compared with referring patients out for more formal nerve conduction studies, shortening the time from presentation to surgery from 198 days to 102 days (p<0.0001). It was also cost effective with a calculated saving to the hospital of more than £70 per patient. The device is easy to use and acceptable to patients and no adverse effects were noted.

Evaluation of electrogustometry and the filter paper disc method for taste assessment.

CONCLUSION: The results indicate that electrogustometry and the filter paper disc method are reliable methods to measure taste with a high degree of reproducibility. OBJECTIVES: To thoroughly evaluate the reliability of electrogustometry and the filter paper disc method for taste assessments. METHODS: Thirty-nine healthy test persons without any history of chronic middle ear disease, aged between 27 and 62 years, were recruited. In all, 772 electrogustometry and 30 filter paper disc assessments were made. A nerve decay test was performed, with measures taken before and after eating sweet, sour, bitter, salt, a mild or spicy meal, after smoking, and after taking Swedish tobacco snuff ('snus'), as well as before and after local anesthesia of the tongue. Measurements were performed on 5 consecutive days and repeatedly during 1 day. The correlation between electrogustometry and the filter paper disc method was also studied. RESULTS: The results indicate that electrogustometry and the filter paper disc method are reliable methods to measure taste with a high degree of reproducibility. The only actions causing significant changes in the electrogustometry readings were eating a bitter substance and having local anesthesia of the tongue. The correlation between the methods was statistically significant except for the bitter flavor, where the correlation was just below the level of significance.