[Fundamental ophthalmology: the role of electrophysiological studies]

Studying of functional aspects of eye disease pathogenesis by electrophysiological methods is widely demanded in fundamental ophthalmology. Introduction of modern methods of functional assessment into experimental and clinical projects significantly broadens knowledge of normal and pathological functioning of the visual system and is the basis for further development of new strategies of pathogenetic treatment, diagnostics and expert evaluation. Some problems of ophthalmology, including those that concern age-related macular degeneration, glaucoma, diabetic retinopathy, and other diseases, are considered in the context of how much electrophysiology contributes to their solution. The role of functional examinations of the retina in studying pathophysiology of neurodegenerative brain diseases, such as Alzheimer's and Parkinson's, is also discussed.

Feasibility and analysis of bipolar concentric recording of electrohysterogram with flexible active electrode

The conduction velocity and propagation patterns of the electrohysterogram (EHG) provide fundamental information on the electrophysiological condition of the uterus. However, the accuracy of these measurements can be impaired by both the poor spatial selectivity and sensitivity to the relative direction of the contraction propagation associated with conventional disc electrodes. Concentric ring electrodes could overcome these limitations. The aim of this study was to examine the feasibility of picking up surface EHG signals using a new flexible tripolar concentric ring electrode (TCRE), and to compare these signals with conventional bipolar recordings. Simultaneous recording of conventional bipolar signals and bipolar concentric EHG (BC-EHG) were carried out on 22 pregnant women. Signal bursts were characterized and compared. No significant differences were found between the channels in either duration or dominant frequency in the Fast Wave High frequency range. Nonetheless, the high pass filtering effect of the BC-EHG recordings gave lower frequency content between 0.1 and 0.2 Hz. Although the BC-EHG signal amplitude was about 5-7 times smaller than that of bipolar recordings, a similar signal-to-noise ratio was obtained. These results suggest that the flexible TCRE is able to pick up uterine electrical activity and could provide additional information for deducing the uterine electrophysiological condition.

Effects of corticosteroid injection on nerve conduction testing for the diagnosis of carpal tunnel syndrome

We conducted a study to determine the change in nerve conduction testing after steroid injection in patients with carpal tunnel syndrome (CTS). One hundred forty-five patients with suspected CTS were targeted for this study. Twenty-seven patients underwent testing before and after injection. Repeat studies were performed 4 to 6 weeks after injection. All data from the electrodiagnostic studies were entered into a database and used for comparison. Before injection, mean (SD) distal motor latency (DML) was 5.01 (0.9) ms, and mean (SD) peak sensory latency (PSL) was 5.01 (0.88) ms. After injection, mean (SD) DML was 4.82 (0.7) ms, and mean (SD) PSL was 4.69 (0.66) ms. Mean (SD) difference between preinjection and postinjection DML was 0.187 (0.45) ms, and mean difference between preinjection and postinjection PSL was 0.319 (0.48) ms. Both differences were statistically significant (paired t test). Our study results showed a statistical difference between testing done before and after steroid injection. These results indicate that injections given before electrodiagnostic testing alter results and may affect patient management.

[Multichannel electrogastrography in pediatrics - progress in standardisation and clinical application]

Electrogastrography (EGG) is a non-invasive method to record gastric myoelectrical activity by means of electrodes placed on the abdominal surface. This technique allows to obtain information about gastric myoelectrical activity and indirectly about gastric motility, without affecting its physiological functions. Except traditional parameters of single channel EGG such as: dominant frequency and power, instability coefficient of dominant frequency and power, percentage of normo-, brady- and tachygastry, the multichannel electrogastrography allows for estimation and registration of the slow waves coupling and propagation as well as to improve detection of abnormalities in gastric myoelectrical activity. Many agents connected with signal detection and analysis, test meal and normative values affect the final result of EGG recording. The trials defining normative data for healthy children and optimal composition of the test meal are conducted. It seems that the establishment of standard protocol of EGG is essential. EGG in children is useful in variety of functional gastrointestinal disorders, as well as gastroesophageal reflux disease and some organic disorders e.g. diabetes mellitus. Some of these diseases are connected with gastric myoelectrical activity abnormalities but others are not easily associable with them and as such are in need of additional investigations. Despite of a rapid development of electrogastrography difficulties in finding correlations between disturbances in myoelectric stomach function and gastric motility, impaired gastric emptying and symptoms of particular disease still remain. On the other hand a normal EGG does not exclude the disease.

The forward problem of electroarthrography: modeling load-induced electrical potentials at the surface of the knee

Electroarthrography (EAG) is a novel technology recently proposed to detect cartilage degradation. EAG consists of recording electrical potentials on the knee surface while the joint is undergoing compressive loading. Previous results show that these signals originating from streaming potentials in the cartilage reflect joint cartilage health. The aim of this study is to contribute to the understanding of the generation of the EAG signals and to the development of interpretation criteria using computer models of the human knee. The knee is modeled as a volume conductor composed of different regions characterized by specific electrical conductivities. The source of the EAG signal is the load-induced interstitial fluid flow that transports ions within the compressed cartilage. It is modeled as an impressed current density in different sections of the articular cartilage. The finite-element method is used to compute the potential distribution in two knee models with a realistic geometry. The simulated potential distributions correlate very well with previously measured potential values, which further supports the hypothesis that the EAG signals originate from compressed cartilage. Also, different localized cartilage defects simulated as a reduced impressed current density produce specific potential distributions that may be used to detect and localize cartilage degradation. In conclusion, given the structural and electrophysiological complexity of the knee, computer modeling constitutes an important tool to improve our understanding of the generation of EAG signals and of the various factors that affect the EAG signals so as to help develop the EAG technology as a useful clinical tool.

Cardiac magnetic resonance and electroanatomical mapping of acute and chronic atrial ablation injury: a histological validation study

AIMS

To provide a comprehensive histopathological validation of cardiac magnetic resonance (CMR) and endocardial voltage mapping of acute and chronic atrial ablation injury.

METHODS AND RESULTS

16 pigs underwent pre-ablation T2-weighted (T2W) and late gadolinium enhancement (LGE) CMR and high-density voltage mapping of the right atrium (RA) and both were repeated after intercaval linear radiofrequency ablation. Eight pigs were sacrificed following the procedure for pathological examination. A further eight pigs were recovered for 8 weeks, before chronic CMR, repeat RA voltage mapping and pathological examination. Signal intensity (SI) thresholds from 0 to 15 SD above a reference SI were used to segment the RA in CMR images and segmentations compared with real lesion volumes. The SI thresholds that best approximated histological volumes were 2.3 SD for LGE post-ablation, 14.5 SD for T2W post-ablation and 3.3 SD for LGE chronically. T2-weighted chronically always underestimated lesion volume. Acute histology showed transmural injury with coagulative necrosis. Chronic histology showed transmural fibrous scar. The mean voltage at the centre of the ablation line was 3.3 mV pre-ablation, 0.6 mV immediately post-ablation, and 0.3 mV chronically.

CONCLUSION

This study presents the first histopathological validation of CMR and endocardial voltage mapping to define acute and chronic atrial ablation injury, including SI thresholds that best match histological lesion volumes. An understanding of these thresholds may allow a more informed assessment of the underlying atrial substrate immediately after ablation and before repeat catheter ablation for atrial arrhythmias.

Higher diagnostic yield with the combined sensory index in mild carpal tunnel syndrome

OBJECTIVES

The combined sensory index (CSI), a sensitive composite score of 3 median sensory comparison studies, may still be underutilized in diagnosing mild cases of carpal tunnel syndrome (CTS). Our goal was to compare the effectiveness of the "standard" median digit 2 (D2) sensory study to a CSI algorithm in diagnosing mild CTS.

METHODS

We retrospectively identified patients with typical CTS symptoms and signs. Electrodiagnostically normal patients and those having mild CTS diagnosed by D2 or CSI algorithm were separated into groups.

RESULTS

Seventy-four patients were included, and 51 (68.9%) were diagnosed with mild CTS. Of the 51, 31 (60.8%) were diagnosed using the CSI algorithm, and 20 (39.2%) were diagnosed using D2 (P < 0.001).

CONCLUSIONS

Our data suggest that the CSI algorithm is significantly more effective than the D2 to diagnose mild CTS. If mild CTS is diagnosed earlier, treatment can be initiated sooner and morbidity can likely prevented.

Visualization of the diaphragm muscle with ultrasound improves diagnostic accuracy of phrenic nerve conduction studies

INTRODUCTION

Evaluation of phrenic neuropathy (PN) with phrenic nerve conduction studies (PNCS) is associated with false negatives. Visualization of diaphragmatic muscle twitch with diaphragm ultrasound (DUS) when performing PNCS may help to solve this problem.

METHODS

We performed bilateral, simultaneous DUS-PNCS in 10 healthy adults and 12 patients with PN. The amplitude of the diaphragm compound muscle action potential (CMAP) (on PNCS) and twitch (on DUS) was calculated.

RESULTS

Control subjects had <38% side-to-side asymmetry in twitch amplitude (on DUS) and 53% asymmetry in phrenic CMAP (on PCNS). In the 12 patients with PN, 12 phrenic neuropathies were detected. Three of these patients had either significant side-to-side asymmetry or absolute reduction in diaphragm movement that was not detected with PNCS. There were no cases in which the PNCS showed an abnormality but the DUS did not.

CONCLUSIONS

The addition of DUS to PNCS enhances diagnostic accuracy in PN.

Ulnar entrapment neuropathy in patients with type 2 diabetes mellitus: an electrodiagnostic study

AIMS

This study aimed to assess the prevalence and electrophysiological features of ulnar entrapment neuropathy in patients with type 2 diabetes mellitus (DM).

METHODS

Nerve conduction studies (NCS) were performed in a sample of consecutive diabetic patients aged 25-75 years, referred by the Diabetology Unit. NCS of the median, ulnar, radial, peroneal and sural nerves were performed on the non-dominant side. Median entrapment neuropathy at the wrist (MNW) and ulnar neuropathy at the elbow (UNE) and wrist (UNW) were diagnosed according to standard electrodiagnostic criteria.

RESULTS

Sixty-four patients were enrolled, 28 male (44%), average age 61, average DM duration 14.5 years. Polyneuropathy was diagnosed in 45 subjects (70%). UNE was detected in 22 patients (34%) (4 did not have polyneuropathy), in the abductor digiti minimi in 16, the first interosseus in 14 and in both in 8. UNW was detected in 7 (11%) subjects and MNW in 40 (63%). NCS alterations consistent with ulnar neuropathy were detected in a high proportion of patients (45%), suggesting that the ulnar nerve is very susceptible to focal entrapment in DM.

CONCLUSIONS

Upper limb sensory and motor NCS, including motor conduction velocity across the elbow, should be considered in the staging of DM patients.

Electrodiagnostic evaluation of patients with carpal tunnel syndrome regarding the presence of subjective and physical findings

The aim of our study was to evaluate the changes of median nerve conduction velocities by electrodiagnostic procedure in carpal tunnel syndrome (CTS) patients with and without present subjective and physical findings. We have evaluated 116 patients that were diagnosis with CTS. Subjective findings: weakness, numbness and night pain were analyzed. Further physical findings were evaluated: Tinels sign, muscles hypotrophy and weakness according to muscle manual test (MMT). Duration of complaints was evaluated as well. Electroneurographic findings included: estimation of median nerve motor terminal latency (mMTL), sensory velocity (mSV) and motor velocity (mMV). Significantly longer complaints were present in patients who experienced night pain (p=0.015) and those with muscles weakness on MMT (p=0.016). Statistically significant increase for mMTL values was noticed for patients with Tinels sign (p=0.045), present muscles hypotrophy (p=0.001) and weakness on MMT (p=0.001). There is significant decrease for mMV in group with present Tinels sign (p=0.048), muscle hypotrophy (p=0.003) and weakness on MMT (p=0.002), and for mSV in group with present muscle hypotrophy (p=0.008) and group with weakness on MMT (p=0.019). Multivariate logistic regressional analysis shown that only for hypotrophy, mMTL variable presents significant independent contributor (p=0.009). For the diagnosis confirmation and treatment planning along with elecroneurography it is necessary to evaluate patients with CTS clinically, since different clinical manifestations are correlating in different degree with electroneurographic findings.

Similarities between neuropathic pruritus sites and lichen simplex chronicus sites

BACKGROUND

Localized itch of non-pruritoceptive origin is often neuropathic and may be referred to as neuropathic itch syndrome.

OBJECTIVES

To describe the results of nerve conduction studies in patients with anogenital pruritus, brachioradial pruritus and scalp dysesthesia, and compare these sites to typical sites of lichen simplex chronicus (LSC).

METHODS

The study summarizes previously published data combined with unpublished data of patients with scalp dysesthesia. Nerve conduction studies included measurements of distal sensory and motor latency, conduction velocity and F-responses.

RESULTS

A neuropathy was demonstrated in 29 of 36 patients with anogenital pruritus (80.5%), 8/14 with brachioradial pruritus (57.1%) and 4/9 with scalp dysesthesia (44.4%). The typical sites overlapped with some but not all LSC sites.

CONCLUSIONS

A considerable proportion of patients with brachioradial pruritus, anogenital pruritus and scalp dysesthesia have abnormal nerve conduction findings, suggesting a neuropathic origin. The skin sites overlap with some common LSC sites, suggesting that in some cases of LSC a local neuropathy could be a possible cause.

Guyon's tunnel syndrome during pregnancy with concomitant anomalous arch of the ulnar nerve: a case report

Numerous causes are reported for ulnar nerve compression at the wrist, known as Guyon's tunnel syndrome. In the present article, a patient with Guyon's tunnel syndrome during pregnancy concomitant with an anomaly of ulnar nerve is described. A 29-year-old Iranian woman presented with clinical features of Guyon's tunnel syndrome (pain and paresthesia in the fifth finger of the left hand and atrophy of the first dorsal interosseus muscle). Symptoms of the patient appeared during the third trimester of pregnancy. Electro diagnostic studies confirmed Guyon's tunnel syndrome. Surgical exploration revealed an anomalous arch of the ulnar nerve passing through the flexor carpi ulnaris (FCU) tendon. The anomalous arch of the ulnar nerve was released by resection of the segment of FCU tendon passing through the ulnar nerve arch. Therefore, in patients with Guyon's tunnel syndrome, the ulnar nerve anomaly should be kept in mind as a cause. Moreover, pregnancy may have a provocative effect on Guyon's tunnel syndrome similar to carpal tunnel syndrome (CTS).

[Syndrome of diabetic foot: modern diagnostic methods]

We summarize the literature data on diagnostics of diabetic foot syndrome including clinical examination and special invasive and non-invasive studies of the vascular system. The main methods are ultrasound dopplerography, X-ray contrast angiography, and ultrasound duplex scanning. Special attention is given to instrumental diagnostics of diabetic neuropathies. The golden standard for the evaluation of the function of the peripheral nervous system is electroneuromyography. Methods for the study of diabetic foot complications, such as osteoarthropathy and trophic ulcers, are discussed.

Relationship between Semmes-Weinstein Monofilaments perception Test and sensory nerve conduction studies in Carpal Tunnel Syndrome

BACKGROUND

The Semmes-Weinstein Monofilament Test (SWMT) is a clinical widely used test to quantify the sensibility in patients with Carpal Tunnel Syndrome (CTS). No study has investigated the relationship between the SWMT and sensory nerve conduction studies (SNCS) in patients with CTS.

OBJECTIVE

To assess the relationship between the SWMT and SNCS findings in patients with CTS.

METHODS

This cross-sectional clinical measurement study included 35 patients with CTS (55 hands) with a mean age of 45 ± 12 years. The outcome measures were the SWMT and SNCS measures of distal latency (DLs), amplitude (AMPs), and nerve conduction velocity (NCV). The median innervated fingers were tested using SWMT and electrodiagnostic tests. The primary outcome was the correlations between the SWMTs and NCS measures.

RESULTS

All of the patients/hands had abnormal NCS findings. When looking at the three digits of interest (thumb, index and middle), the thumb SWMTs had the highest number of abnormal findings (58.2%), with the middle digit having the lowest (45.5%). All NCS findings were statistically different between abnormal and normal thumb SWMTs and abnormal and normal total summed SWMTs. There were significant moderate correlations between thumb SWMT scores and all NCS outcomes.

CONCLUSIONS

Although only approximately 50% of the CTS diagnosed through NCS are corroborated through SWMT; the significant associations between SWMT and NCS measures suggest that SWMT is a valid test for assessing sensations in patients with CTS.

Supraclavicular neuropathy after surgical treatment of clavicular fractures: comparison of two incisions

PURPOSE Of

THE STUDY

To compare the clinical results of clavicular fractures operated by superior locking plate using either horizontal or vertical incision by physical examination and nerve conduction tests.

MATERIAL AND METHODS

Between January 2010 and January 2013, 63 patients with displaced midshaft clavicle fracture were treated with superior locking plate (22 female, 41 male) with either horizontal (n = 38) or vertical incisions (n = 25). Mean interval between trauma and surgery was 3 days (1 to 8 days). Electrodiagnostic tests were performed to 15 patients who felt numbness across their shoulder or chest and ASES test was performed to each of the patient 12 weeks postoperatively. IBM SPSS Statistics 22 (IBM SPSS, Türkiye) programme was used for statistical analysis. Student t-test was used for comparison of normally distributed parameters (quantity) and continuity (yates) test was used. p < 0.05 was accepted to be statistically signifiant.

RESULTS

8 patients of the horizontal incision group and 7 patients of the vertical incision group described numbness across their shoulders. 14 patients had abnormal sensorial electrodiagnostic fidings. Comparison of electrodiagnostic fidings did not reveal any statistical signifiance. The mean ASES score of the affected shoulder was 76.39 ±1.20 in the horizontal group, in the vertical group it was found to be 79.00 ± 2.5 ( p < 0.01).

CONCLUSIONS

Electrodiagnostic study revealed similar results in both groups. According to these results, signifiant difference in mean ASES scores of both groups was not related to sensorial injury of the supraclavicular nerve.

Improvement of diagnostic rate of carpal tunnel syndrome with additional median-to-ulnar comparative nerve conduction studies

PURPOSE

The aim of this study is to assess whether additional median -to-ulnar comparative tests will improve the diagnostic rate of carpal tunnel syndrome (CTS).

METHODS

We recruited 248 hands of 162 CTS patients, and 166 hands of 83 controls. One hundred and sixty-eight (68%) symptomatic hands had abnormal median distal latencies or palm-wrist latencies. We performed three additional comparative tests in the remaining symptomatic hands and the non-CTS hands. The first test compared median distal motor latency (MDL) recorded from the second lumbrical muscle (2L) and ulnar distal latency recorded from interossei muscles (INT) (2L-INT). The second test compared median and ulnar antidromic sensory latencies (MS-US). And the third test compared median and ulnar nerve latencies in the palm-to-wrist segment (PM-PU).

RESULTS

In control subjects, upper limits of median-to-ulnar differences were: 2L-INT= 0.4 ms, MS-US= 0.5 ms, PM-PU= 0.4 ms. In CTS patients with normal conventional electrodiagnostic methods, MS-US difference showed the lowest sensitivity (21.3%). The diagnostic sensitivity of 2L-INT was 27.5% and PM-PU 47.5%. With PM-PU test, additional 15.3% diagnostic rate could be got.

CONCLUSION

For CTS patients with normal results from the standard methods, PM-PU is a good additional comparative test to further improve diagnostic rate.

Electropalatography as an adjunct to nonspeech orofacial myofunctional disorder assessments: a feasibility study

The purpose of this study was to determine if electropalatography (EPG) would be a useful adjunct and feasible option for those conducting clinical assessments of individuals with suspected nonspeech orofacial myofunctional disorders (NSOMD). Three females (two adults, one child) were referred by their orthodontist for assessment of suspected NSOMD. Three adults and one child without NSOMD were recruited for the purpose of evaluating methodological construct, and to provide comparisons for participants with NSOMD. Using EPG, lingual-palatal timing and contact patterns of 105 saliva swallows (45 with NSOMD, 60 without NSOMD) were analyzed by compartmentalizing the sensor display and tracking the order and duration of activation. Lingual-palatal contact patterns were compared in terms of four stages: prepropulsion, propulsion, postpropulsion, release. Coding the lingual-palatal activation in an operationalized manner was a valuable adjunct for describing lingual-palatal timing and contact patterns. Participants with NSOMD showed unique lingual-palatal contact patterns that differed from the patterns of the participants without NSOMD, and from each other. EPG is a potential adjunct to the non-instrumental assessment of NSOMD. Larger scale investigations using EPG should proceed.

Assessing decreased sensation and increased sensory phenomena in diabetic polyneuropathies

Loss of sensation and increased sensory phenomena are major expressions of varieties of diabetic polyneuropathies needing improved assessments for clinical and research purposes. We provide a neurobiological explanation for the apparent paradox between decreased sensation and increased sensory phenomena. Strongly endorsed is the use of the 10-g monofilaments for screening of feet to detect sensation loss, with the goal of improving diabetic management and prevention of foot ulcers and neurogenic arthropathy. We describe improved methods to assess for the kind, severity, and distribution of both large- and small-fiber sensory loss and which approaches and techniques may be useful for conducting therapeutic trials. The abnormality of attributes of nerve conduction may be used to validate the dysfunction of large sensory fibers. The abnormality of epidermal nerve fibers/1 mm may be used as a surrogate measure of small-fiber sensory loss but appear not to correlate closely with severity of pain. Increased sensory phenomena are recognized by the characteristic words patients use to describe them and by the severity and persistence of these symptoms. Tests of tactile and thermal hyperalgesia are additional markers of neural hyperactivity that are useful for diagnosis and disease management.

Orthodontic-surgical treatment: neuromuscular evaluation in open and deep skeletal bite patients

BACKGROUND

The aim of this study was to compare electromyographic data of two groups of patients (open and deep skeletal bite) before and after surgical orthodontic treatment.

METHODS

All patients who underwent orthognathic surgery at the Department of Orthodontics (University of Milan) were subjected to periodic electromyographic evaluation of the masticatory muscles (masseter and anterior temporal muscles) and to electrokinesiographic evaluation of mandibular movements. The sample comprised 72 patients (35 open skeletal bite patients and 37 deep skeletal bite patients) at the end of craniofacial growth. The electromyographic instruments used in the study included a Freely and a K6-I electromyograph. Statistical evaluation was carried out with Student's t tests for independent samples.

RESULTS

Lots of differences between open and deep skeletal bite patients have been underlined by the analysis of the electromyographic data obtained. These results have been obtained with both electromyographic systems. Muscular activity in microvolts is higher in deep skeletal bite patients at the beginning of the treatment than in open bite ones, but during the following phases of the treatment, the two values became similar.

CONCLUSIONS

Morphologic differences between open and deep bite patients can also be demonstrated by instrumental examinations, and their correction after surgical treatment is observable on electromyographic and electrognatographic exams.

Measuring body layer vibration of vocal folds by high-frame-rate ultrasound synchronized with a modified electroglottograph

The body-cover concept suggests that the vibration of body layer is an indispensable component of vocal fold vibration. To quantify this vibration, a synchronized system composed of a high-frame-rate ultrasound and a modified electroglottograph (EGG) was employed in this paper to simultaneously image the body layer vibration and record the vocal fold vibration phase information during natural phonations. After data acquisition, the displacements of in vivo body layer vibrations were measured from the ultrasonic radio frequency data, and the temporal reconstruction method was used to enhance the measurement accuracy. Results showed that the modified EGG, the waveform and characteristic points of which were identical to the conventional EGG, resolved the position conflict between the ultrasound transducer and EGG electrodes. The location and range of the vibrating body layer in the estimated displacement image were more clear and discernible than in the ultrasonic B-mode image. Quantitative analysis for vibration features of the body layer demonstrated that the body layer moved as a unit in the superior-inferior direction during the phonation of normal chest registers.

One-year evolution of ulnar somatosensory potentials after trauma in 365 tetraplegic patients: early prediction of potential upper limb function

Early prediction of hand function is crucial for efficient rehabilitation of cervical spinal cord injury (cSCI). This study investigated correlations between ulnar somatosensory evoked potentials (ulnar SSEPs) and functional outcome of hand function following acute traumatic cervical cord injury. Neurological assessment of sensory scores and hand function were compared with five ulnar SSEP categories of similar persistence and quality in 365 patients throughout the first year after cSCI. Of the 365 patients, 218 (68%) exhibited ulnar SSEP potentials at any one stage during the year, and in 147 patients (40.3%) ulnar SSEPs were obtainable at every assessment stage. While ulnar SSEP latency and amplitude assessments remained largely unchanged over time in the majority of patients, hand function improved remarkably during the first year following cSCI. One year outcome of hand function was predetermined by ulnar SSEP category due to distinct differences in the ulnar SSEP parameters. Additionally, an early prognostic group allocation by ulnar SSEP criteria at the first assessment stage within 4 weeks after spinal trauma allowed reliable prediction of hand function outcome after 1 year. We conclude that early assessment of ulnar SSEP as a non-invasive and objective neurophysiological test is a valuable marker of prospective hand function and independence 1 year after cSCI. This could be most relevant for planning neurorehabilitation, and in prospective clinical SCI trials.

PURLs: Suspect carpal tunnel? Try this

An easy-to-administer modification of the traditional Phalen’s test for carpal tunnel syndrome increases the value of this diagnostic tool.

Evaluation and diagnosis of wrist pain: a case-based approach

Patients with wrist pain commonly present with an acute injury or spontaneous onset of pain without a definite traumatic event. A fall onto an outstretched hand can lead to a scaphoid fracture, which is the most commonly fractured carpal bone. Conventional radiography alone can miss up to 30 percent of scaphoid fractures. Specialized views (e.g., posteroanterior in ulnar deviation, pronated oblique) and repeat radiography in 10 to 14 days can improve sensitivity for scaphoid fractures. If a suspected scaphoid fracture cannot be confirmed with plain radiography, a bone scan or magnetic resonance imaging can be used. Subacute or chronic wrist pain usually develops gradually with or without a prior traumatic event. In these cases, the differential diagnosis is wide and includes tendinopathy and nerve entrapment. Overuse of the muscles of the forearm and wrist may lead to tendinopathy. Radial pain involving mostly the first extensor compartment is commonly de Quervain tenosynovitis. The diagnosis is based on history and examination findings of a positive Finkelstein test and a negative grind test. Nerve entrapment at the wrist presents with pain and also with sensory and sometimes motor symptoms. In ulnar neuropathies of the wrist, the typical presentation is wrist discomfort with sensory changes in the fourth and fifth digits. Activities that involve repetitive or prolonged wrist extension, such as cycling, karate, and baseball (specifically catchers), may increase the risk of ulnar neuropathy. Electrodiagnostic tests identify the area of nerve entrapment and the extent of the pathology.

The midline electroneurography method for facial palsy reflects total nerve degeneration

CONCLUSION

The midline electroneurography (ENoG) method might reflect total facial nerve degeneration.

OBJECTIVE

We compared ENoG values in patients with facial palsy using two different methods, the midline method and five electroneurogram recordings, to reveal whether the ENoG value obtained with the midline method reflects total facial nerve degeneration.

METHODS

Forty patients with facial palsy were enrolled. Compound muscle action potentials (CMAPs) were recorded using the midline method, in which the anode was placed on the mental protuberance and the cathode was placed on the philtrum. Additionally, five electroneurogram recordings were obtained by placing the anode on the skin of the parietal region and five cathodes on the skin over five facial muscles (frontalis, orbicularis oculi, nasalis, orbicularis oris, and depressor anguli oris muscles). ENoG values recorded using the two methods were compared.

RESULTS

The ENoG values of the five facial muscles did not differ from those obtained using the midline method. The total ENoG value calculated by summing five CMAPs from five facial muscles, which is considered to reflect total facial nerve degeneration, was not significantly different from that using midline methods; moreover, a strong positive correlation coefficient (r = 0.87) was found between them.

Survival in out-of-hospital cardiac arrests with initial asystole or pulseless electrical activity and subsequent shockable rhythms

BACKGROUND

Non-shockable arrest rhythms (pulseless electrical activity and asystole) represent an increasing proportion of reported cases of out-of-hospital cardiac arrest (OHCA). The prognostic significance of conversion from non-shockable to shockable rhythms during the course of resuscitation remains unclear.

OBJECTIVE

To evaluate whether out-of-hospital cardiac arrest survival with initially non-shockable arrest rhythms is improved with subsequent conversion to shockable rhythms.

METHODS

Secondary analysis of data in Epistry - Cardiac Arrest, an epidemiologic registry maintained by the Resuscitation Outcomes Consortium (ROC). This analysis includes OHCA events from December 1, 2005 through May 31, 2007 contributed by six US and two Canadian sites. For all EMS-treated adult (18 and older) cardiac arrest patients who presented with non-shockable cardiac arrest, we compared survival to hospital discharge between patients who did develop a shockable rhythm and those who did not based on receipt of subsequent defibrillation. Missing data were handled using multiple imputation. Multivariable logistic regression was used to adjust for potentially confounding variables.

RESULTS

A total of 6556 EMS treated adult cardiac arrest cases presented in non-shockable rhythms. Survival to discharge in patients who converted to a shockable rhythm was 2.77% while survival in those who did not was 2.72% (p=0.92). After adjusting for confounders, conversion to a shockable rhythm was not associated with improved survival (OR 0.88, 95% CI: 0.60-1.30).

CONCLUSION

For OHCA patients presenting in PEA/asystole, survival to hospital discharge was not associated with conversion to a shockable rhythm during EMS resuscitation efforts.

Upper motor neuron involvement in amyotrophic lateral sclerosis evaluated by triple stimulation technique and diffusion tensor MRI

The objective of this study was to evaluate the diagnostic value of triple stimulation technique (TST) and diffusion tensor imaging (DTI) tractography as markers of upper motor neuron (UMN) degeneration in amyotrophic lateral sclerosis (ALS). Fourteen ALS patients fulfilling the El Escorial criteria and 30 control subjects participated in the study. TST amplitude and area ratio were used as an estimate of the degree of central motor conduction failure. DTI fractional anisotropy was used as a quantitative measure of the structural integrity of the corticospinal tract and the posterior limb of the internal capsule. Mean TST amplitude and area ratio were lower in patients than controls, while there were no differences in mean fractional anisotropy of the corticospinal tract or the posterior limb of the internal capsule. TST was abnormal in 7/13 patients (sensitivity 54%) and DTI was abnormal in 3/12 (sensitivity 25%). Combining TST and DTI disclosed abnormalities in 8/11 patients (sensitivity 73%). TST confirmed UMN degeneration in one of every 2.25 patient in the diagnostic categories lower than 'probable' ALS. Using results from TST as a criterion for UMN degeneration, four patients in diagnostic categories lower than 'probable' ALS and without clinical signs of UMN degeneration in the cervical region increased in diagnostic category. Our findings indicate that TST has a significant diagnostic value as an early objective marker of UMN degeneration in ALS, while the value of DTI analysis seems limited.

[Electroglottography - an objective method for the evaluation of the vocal function in the children: reliability and validity]

The objective of the present study was to estimate the relevance and validity of the electroglottographic technique as a method for diagnostics of voice disorders in children. The authors analyse the normative data on the vocal disorders in the children obtained by electroglottography (EGT) and assess the value of this technique for the control of treatment of dysphonia of different etiology. It is shown that that dynamics of these findings (before and after the treatment including their comparison with age-related normative data) attains statistical significance . It is concluded that the results of EGT can be regarded as the important diagnostic criteria for the effectiveness and quality of the treatment of dysphonia of different origin in children.

Comprehensive quantification of the spastic catch in children with cerebral palsy

In clinical settings, the spastic catch is judged subjectively. This study assessed the psychometric properties of objective parameters that define and quantify the severity of the spastic catch in children with cerebral palsy (CP). A convenience sample of children with spastic CP (N=46; age range: 4-16 years) underwent objective spasticity assessments. High velocity, passive stretches were applied to the gastrocnemius (GAS) and medial hamstrings (MEH). Muscle activity was measured with surface electromyography (sEMG), joint angle characteristics using inertial sensors and reactive torque using a force sensor. To test reliability, a group of 12 children were retested after an average of 13 ± 9 days. The angle of spastic catch (AOC) was estimated by three biomechanical definitions: joint angle at (1) maximum angular deceleration; (2) maximum change in torque; and (3) minimum power. Each definition was checked for reliability and validity. Construct and clinical validity were evaluated by correlating each AOC definition to the averaged root mean square envelope of EMG (RMS-EMG) and the Modified Tardieu Scale (MTS). Severity categories were created based on selected parameters to establish face validity. All definitions showed moderate to high reliability. Significant correlations were found between AOC3 and the MTS of both muscles and the RMS-EMG of the MEH, though coefficients were only weak. AOC3 further distinguished between mild, moderate and severe catches. Objective parameters can define and quantify the severity of the spastic catch in children with CP. However, a comprehensive understanding requires the integration of both biomechanical and RMS-EMG data.

[Buccal epithelium as an object for testing of biological age and the speed of aging]

Testing of biological age and the speed of aging is one of the main goal of gerontology and predictive medicine. This review summarizes the ability of using buccal epithelium as target of non-invasive investigation of aging diagnostics. Buccal epithelium used for thelomere test and morphological characteristics of its nucleus demonstrate the speed of aging. The electrophysiological investigation of buccal cells nucleus are the markers of biological age of a human. In future it can be possible to use buccal epithelium for immunogistochemical investigation with goal to diagnose cellular senescence.

Effectiveness of different sensing modalities in predicting targets of reaching movements

Human motion recognition is essential for many biomedical applications, but few studies compare the abilities of multiple sensing modalities. This paper thus evaluates the effectiveness of different modalities when predicting targets of human reaching movements. Electroencephalography, electrooculography, camera-based eye tracking, electromyography, hand tracking and the user's preferences are used to make predictions at different points in time. Prediction accuracies are calculated based on data from 10 subjects in within-subject crossvalidation. Results show that electroencephalography can make predictions before limb motion onset, but its accuracy decreases as the number of potential targets increases. Electromyography and hand tracking give high accuracy, but only after motion onset. Eye tracking is robust and gives high accuracy at limb motion onset. Combining multiple modalities can increase accuracy, though not always. While many studies have evaluated individual sensing modalities, this study provides quantitative data on many modalities at different points of time in a single setting. The information could help biomedical engineers choose the most appropriate equipment for a particular application.

Carpal tunnel syndrome-try these diagnostic maneuvers

Physical maneuvers are an essential step in diagnosing carpal tunnel syndrome. This update can help you get up to speed on diagnosis and treatment.

Intraoperative neurophysiological monitoring of somatosensory evoked potentials during hip arthroscopy surgery

Arthroscopic hip surgery is used to treat many of the causes of hip pain, hip instability, and hip disorders. Hip pain and instability are often caused by injuries to the acetabular labrum. Repairing labral tears, suturing, and debridement involve stabilizing the hip and placing the operative side leg in traction (Phillipon 2006, Phillipon and Schenker 2006) to allow for instrument clearance and to avoid iatrogenic injury to the chondral surfaces. This places the sciatic nerve in a stretched position and may cause temporary or permanent nerve injury. Transient neuropraxia is the most common injury occurring in 5% of the patients undergoing arthroscopic hip surgery (McCarthy and Lee 2006). 35 patients; 24 women and 11 men, (a total of 36 surgeries) were monitored with intraoperative neurophysiological monitoring using somatosensory evoked potentials (SSEPs) during hip arthroscopy for labral repair and femoral head osteoplasty. They ranged in age from 15 to 59 years; mean age: 39.81 years. During surgery 19 (54%) patients experienced significant SSEP waveform changes. Time from placement of traction to loss of signals in those patients experiencing SSEP changes ranged from 7 minutes to 46 minutes. Recovery of SSEP signals ranged from 2 minutes to over 15 minutes when the traction of the leg was released. Surgeries ranged from 2 to 4 hours; mean: 2.78 hours. These findings show that neuromonitoring during hip arthroscopic labral repair and debridement procedures might be useful to prevent temporary and permanent neural tissue injuries.

Simple clinical tests in severe carpal tunnel syndrome

Patients with severe carpal tunnel syndrome may be characterised by an atypical clinical picture. They assess complaints as becoming less bothersome than in the past. It seems that this may influence the diagnostic value of some clinical tests used in physical examinations. The aim of the study was the selection of the most reliable clinical tests in a group of patients with severe carpal tunnel syndrome.

MATERIAL AND METHODS

The material comprised 38 cases of severe form of the disease in a group of 37 prospective patients. The methods consisted in the evaluation of the rate of positive results of selected clinical tests, and in the comparison of their statistical correlation with selected parameters of median nerve conduction.

RESULTS

The study results indicated that high incidence of two-point discrimination disorders showed a correlation with the sensory conduction parameters, including the median-ulnar sensory latency difference. The Durkan's and Phalen's tests were positive in almost all patients with advanced carpal tunnel. The Katz hand diagram revealed significantly enhanced sensitivity in the "probable" pattern.

CONCLUSIONS

We speculate that the two-point discrimination, evaluated with the use of a simple paper clip, enables the selection of a group of patients with severe form of the syndrome for further differentiation. The tool used for facilitating the differential diagnosis is the Katz hand diagram. The Durkan's and Phalen's tests have an equally high value. However, they show no correlation with the conduction parameters, as measured by EMG.

Electrophysiological contribution of both sensory branches of the superficial peroneal nerve in the diagnosis of peripheral neuropathy

The aim of this study is to evaluate the simultaneous recording of the medial dorsal cutaneous nerve (MDCN) and the intermediate dorsal cutaneous nerve (IDCN) in the investigation of peripheral neuropathy. We obtained MDCN and IDCN recordings in 35 patients with peripheral neuropathy and in 41 healthy subjects to determine the specificity of the sensory nerve action potential (SNAP) amplitude of each branch separately and of both simultaneously by using the maximal amplitude of either branch. The patients with peripheral neuropathy had low MDCN and IDCN SNAP amplitude in 60% and 14.3% respectively. Though, when recording both MDCN and IDCN simultaneously, the maximum peroneal SNAP amplitude was abnormally low in 68.6%. All the healthy individuals had normal IDCN SNAP amplitude; whereas in 9.7% the MDCN SNAP amplitude was lower than normal. In case of simultaneous recording of both branches the maximum SNAP amplitude was normal in all healthy subjects. Conclusively, the simultaneous amplitude recording of the terminal sensory peroneal branches can better detect abnormal responses in patients with peripheral neuropathy.

Surface electromyography for speech and swallowing systems: measurement, analysis, and interpretation

PURPOSE

Applying surface electromyography (sEMG) to the study of voice, speech, and swallowing is becoming increasingly popular. An improved understanding of sEMG and building a consensus as to appropriate methodology will improve future research and clinical applications.

METHOD

An updated review of the theory behind recording sEMG for the speech and swallowing systems is provided. Several factors that are known to affect the content of the sEMG signal are discussed, and practical guidelines for sEMG recording and analysis are presented, focusing on special considerations within the context of the speech and swallowing anatomy.

RESULTS

Unique challenges are seen in application of sEMG to the speech and swallowing musculature owing to the small size of the muscles in relation to the sEMG detection volume and the present lack of knowledge about innervation zone locations.

CONCLUSIONS

Despite the challenges discussed, application of sEMG to speech and swallowing has potential as a clinical and research tool when used correctly and is specifically suited to noninvasive clinical studies using between-condition or between-group comparisons for which detection of specific isolated muscle activities is not necessary.

[The application of wavelet transform and wavelet lifting in signal processing of EGG]

This paper introduced the definition, structure of basis wavelet functions and wavelet lifting. Wavelet transform and wavelet lifting were applied in signal processing of EGG in our study. The characteristics of signal energy, information entropy and joint entropy were analyzed to introduce general selective method of wavelet basis functions after the signals have been filtered. In order to verify the rationality of evaluation criteria, signals of electrogastrogram (EGG) were processed and filtered with different wavelet basis functions in the experiments. Signals of EGG were filtered by wavelet transform and wavelet lifting, slow wave and spike wave of EGG were filtered. And the rationality of wavelet transform, wavelet lifting and effectiveness of EGG filter algorithm were proved by the experimental data. It provided an effective solution for the diagnosis and measurement of gastric diseases.

Electrodiagnostic evaluation of ulnar neuropathy and other upper extremity mononeuropathies

Upper extremity mononeuropathies are some of the common disorders seen in neurophysiology laboratories. Electrophysiologic studies rely on accurate localization based on knowledge of applicable anatomy and features of history and physical examination. Careful electrodiagnostic studies provide an accurate diagnosis, help localize the lesion site, exclude alternate diagnoses, reveal unsuspected diagnoses, determine pathophysiology of lesions, and assess severity, timeframe, and prognosis of lesions. This article discusses the electrodiagnostic approach to ulnar neuropathy, proximal median neuropathy, radial neuropathy, musculocutaneous neuropathy, axillary neuropathy, suprascapular neuropathy, and long thoracic neuropathy. Pertinent aspects of the history and physical examination, nerve conduction studies, and electromyography are presented.

Current trends in pedicle screw stimulation techniques: lumbosacral, thoracic, and cervical levels

Unequivocally, pedicle screw instrumentation has evolved as a primary construct for the treatment of both common and complex spinal disorders. However an inevitable and potentially major complication associated with this type of surgery is misplacement of a pedicle screw(s) which may result in neural and vascular complications, as well as impair the biomechanical stability of the spinal instrumentation resulting in loss of fixation. In light of these potential surgical complications, critical reviews of outcome data for treatment of chronic, low-back pain using pedicle screw instrumentation concluded that "pedicle screw fixation improves radiographically demonstrated fusion rates;" however the expense and complication rates for such constructs are considerable in light of the clinical benefit (Resnick et al. 2005a). Currently, neuromonitoring using free-run and evoked (triggered) electromyography (EMG) is widely used and advocated for safer and more accurate placement of pedicle screws during open instrumentation procedures, and more recently, guiding percutaneous placement (minimally invasive) where the pedicle cannot be easily inspected visually. The latter technique, evoked or triggered EMG when applied to pedicle screw instrumentation surgeries, has been referred to as the pedicle screw stimulation technique. As concluded in the Position Statement by the American Society of Neurophysiological Monitoring (ASNM), multimodality neuromonitoring using free-run EMG and the pedicle screw stimulation technique was considered a practice option and not yet a standard of care (Leppanen 2005). Subsequently, the American Association of Neurological Surgeons/Congress of Neurological Surgeons (AANS/CNS) Joint Section on Disorders of the Spine and Peripheral Nerves published their "Guidelines for the Performance of Fusion Procedures for Degenerative Disease of the Lumbar Spine" (Heary 2005, Resnick et al. 2005a, Resnick et al. 2005b). It was concluded that the "primary justification" of intraoperative neuromonitoring"... is the perception that the safety and efficacy of pedicle screw fixation are enhanced..." (Resnick et al. 2005b). However in summarizing a massive (over 1000 papers taken from the National Library of Medicine), contemporary, literature review spanning nearly a decade (1996 to 2003), this invited panel (Resnick et al. 2005b) recognized that the evidence-based documents contributing to the parts related to pedicle screw fixation and neuromonitoring were "... full of potential sources of error ..." and lacked appropriate, randomized, prospective studies for formulating rigid standards and guidelines. Nevertheless, current trends support the routine use and clinical utility of these neuromonitoring techniques. In particular free-run and triggered EMG have been well recognized in numerous publications for improving both the accuracy and safety of pedicle screw implantation. Currently, treatment with pedicle screw instrumentation routinely involves all levels of the spine - lumbosacral, thoracic, and cervical. Significant historical events, various neuromonitoring modalities, intraoperative alarm criteria, clinical efficacy, current trends, and caveats related to pedicle screw stimulation along the entire vertebral column will be reviewed.

Applying the Kelvin probe to biological tissues: theoretical and computational analyses

The Kelvin probe measures surface electrical potential without making physical contact with the specimen. It relies on capacitive coupling between an oscillating metal tip that is normal to a specimen's surface. Kelvin probes have been increasingly used to study surface and electrical properties of metals and semiconductors and are capable of detecting material surface potentials with submillivolt resolution at a micrometer spatial scale. Its capability for measuring electrical potential without being confounded by electrode-specimen contact makes extending its use towards biological materials particularly appealing. However, the theoretical basis for applying the Kelvin probe to dielectric or partially conductive materials such as biological tissue has not been evaluated and remains unclear. This study develops the theoretical basis underlying Kelvin probe measurements in five theoretical materials: highly conductive, conductive dielectric with rapid charge relaxation, conductive dielectric with slow charge relaxation, perfect dielectric, and tissue with a bulk serial resistance. These theoretically derived equations are then computationally analyzed using parameters from both theoretical specimens and actual biomaterials-including wet skin, dry skin, cerebrospinal fluid, and tendon. Based on these analyses, a Kelvin probe performs in two distinct ways depending on the charge relaxation rates of the sample: The specimen is treated either as a perfect dielectric or as highly conductive material. Because of their rapid relaxation rate and increased permittivity biomaterials behave similarly to highly conductive materials, such as metal, when evaluated by the Kelvin probe. These results indicate that the Kelvin probe can be readily applied to studying the surface potential of biological tissue.

Assessing disease and wellness in the occupational setting: Electrodiagnostic Functional Assessment from wired to wireless

Technology Assessment is the study and evaluation of new technologies. It is based on the premise that developments and discoveries within the scientific and medical communities are relevant to the population at large. Proper technology assessment is an approach that is vital to address the current limitations of the worker's compensation system. The aim of this presentation is to discuss the need for objective diagnostic tools, such as Electrodiagnostic Functional Assessment (EFA), in the workers' compensation system with a focus on musculoskeletal disorders (MSD). Workers' compensation musculoskeletal claims may benefit from a wireless assessment to diagnose and monitor soft tissue injuries and this technology may be applicable to wellness and healthcare programs.

[Comparisons among different reference values of nerve conduction velocity in forensic appraisal]

OBJECTIVE

To provide the evidences for the choice of normal reference value of nerve conduction velocity (NCV) in clinical forensic appraisal.

METHODS

One hundred and fourteen cases with normal peripheral nerve and 155 cases with injured peripheral nerve were collected. The NCV of homonymous nerves in two limbs were detected. In the normal cases, the NCV of the left limbs were used as the normal reference values. The NCV of the right limbs were compared with that of left limbs, the commendatory normal reference values from Beijing Xiehe Hospital and Shanghai Huashan Hospital. In the injured cases, the results of NCV in injuried limbs were compared with the results of healthy limbs and the reference values from Beijing Xiehe Hospital and Shanghai Huashan Hospital.

RESULTS

In the normal group, there was no statistical difference between the left and right limbs in NCV results of homonymous nerve (P > 0.05). The false positive rates (FPR) were 0, 11.4% and 5.2% for three choices normal reference respectively. The false negative rates (FNR) were 0, 9.7% and 12.3% for three choices normal reference in injuried group. Thee false negative cases were all slight nerve injury.

CONCLUSION

The reference value of self-control method could decrease the FPR of normal cases and FNR of injured cases. In clinical forensic appraisal of peripheral nerve, the nerve condition study results from healthy homonymous nerve should be regarded as the reference value at first, supplemented by reference values from clinical labs.

Functional analysis of general odorant binding protein 2 from the meadow moth, Loxostege sticticalis L. (Lepidoptera: Pyralidae)

Odorant binding proteins play a crucial role in transporting semiochemicals across the sensillum lymph to olfactory receptors within the insect antennal sensilla. In this study, the general odorant binding protein 2 gene was cloned from the antennae of Loxostege sticticalis, using reverse transcription PCR and rapid amplification of cDNA ends. Recombinant LstiGOBP2 was expressed in Escherichia coli and purified by Ni ion affinity chromatography. Real-time PCR assays indicated that LstiGOBP2 mRNA is expressed mainly in adult antennae, with expression levels differing with developmental age. Ligand-binding experiments using N-phenyl-naphthylamine (1-NPN) as a fluorescent probe demonstrated that the LstiGOBP2 protein has binding affinity to a broad range of odorants. Most importantly, trans-11-tetradecen-1-yl acetate, the pheromone component of Loxostege sticticalis, and trans-2-hexenal and cis-3-hexen-1-ol, the most abundant plant volatiles in essential oils extracted from host plants, had high binding affinities to LstiGOBP2 and elicited strong electrophysiological responses from the antennae of adults.

[Multiple abnormal innervation of the hand in one patient. Electrophysiological diagnosis]

INTRODUCTION

Nerve anastomoses in the hand are deviations from the anatomical norm. They do not lead to illness, but still they are events related with electrodiagnostic difficulties and, due to their unexpected presentation, also with iatrogenesis in regional surgical interventions.

CASE REPORT

We report the neurophysiological study conducted on a 45-year-old female who was found to have Riche-Cannieu-type motor anastomosis between the median and ulnar branches in the palm of the hand, complete innervation of the 4th finger by the ulnar nerve and complete innervation by the superficial radial of the back of the hand.

CONCLUSIONS

Anatomical descriptions of abnormal innervations in the hand are frequent, especially of the sensory kind. They do not usually give rise to any problems, even when the communicating branch is injured, probably owing to the scant participation of axons that usually occurs in anastomosis. They are not difficult to recognise by means of electroneurography if we are aware of their different types and we have a good knowledge of the anatomical routes. This will enable us to develop accurate diagnostic protocols. Knowledge of these variants will prevent electrodiagnostic errors and surgical iatrogenic effects from occurring.

Electropalatographic specification of Croatian fricatives /s/ and /z/

Electropalatographic specification of alveolar fricatives in Croatian is aimed at providing speech therapists with normative data about the range of acceptable productions of /s/ and /z/ in adult speakers of Croatian. Four variables were analysed: place of articulation, total contact, groove width and hold phase duration. Intra- and inter-speaker variability for each variable was analysed. Lingual palatal cues for voicing difference were also quantified and discussed. Results show that Croatian /s/ and /z/ are alveolar and not dental as previously reported. The comparison between the voiced and the voiceless fricative shows that durational measures provide the best differentiation. The voiceless counterpart is significantly longer. The difference between voiced and voiceless is also found in the total contact, with /z/ having more contact in the anterior four rows of electrodes, while /s/ has more contact in the posterior four rows of electrodes. This difference is also reflected in the anterior and the posterior groove widths. Possibilities of using these results as normative data for the diagnosis and treatment of atypical articulation of /s/ and /z/ are discussed.

Hyperventilation provokes symptoms of carpal tunnel syndrome

Hyperventilation causes respiratory alkalosis. The nervous system is more excitable in alkalosis. This phenomenon can be observed as paraesthesia in fingers and toes as well as around the lips in anxious patients breathing rapidly. We wanted to test this phenomenon on already irritable nerves like the median nerve in carpal tunnel syndrome (CTS). We deployed 50 patients who came in to the day case unit for carpal tunnel decompression with electro-physiologically proven diagnosis. We devised a test whereby patients were made to hyperventilate under prescribed conditions and repeated Phalen's test and Tinel's sign for comparison. These were compared with a control group chosen randomly among hospital staff. 86% patients had a positive result which was just behind Phalen's test in sensitivity. It was also 100% specific as there were no false positives. Hyperventilation is a phenomenon which provokes carpal tunnel syndrome. Its clinical value remains to be seen due to cumbersome method and probable patient non-compliance but it is a new discovery. It may be useful in other irritable-nerve-syndromes as a test to add to our available armament. It may be an additional factor or a primary reason for nocturnal paraesthesias in CTS patients.