Computerized classification of corpus cavernosum electromyogram signals by the use of discriminant analysis and artificial neural networks to support diagnosis of erectile dysfunction

Cardiovascular/Stroke Risk Assessment in Patients with Erectile Dysfunction-A Role of Carotid Wall Arterial Imaging and Plaque Tissue Characterization Using Artificial Intelligence Paradigm: A Narrative Review

PURPOSE

The role of erectile dysfunction (ED) has recently shown an association with the risk of stroke and coronary heart disease (CHD) via the atherosclerotic pathway. Cardiovascular disease (CVD)/stroke risk has been widely understood with the help of carotid artery disease (CTAD), a surrogate biomarker for CHD. The proposed study emphasizes artificial intelligence-based frameworks such as machine learning (ML) and deep learning (DL) that can accurately predict the severity of CVD/stroke risk using carotid wall arterial imaging in ED patients.

METHODS

Using the PRISMA model, 231 of the best studies were selected. The proposed study mainly consists of two components: (i) the pathophysiology of ED and its link with coronary artery disease (COAD) and CHD in the ED framework and (ii) the ultrasonic-image morphological changes in the carotid arterial walls by quantifying the wall parameters and the characterization of the wall tissue by adapting the ML/DL-based methods, both for the prediction of the severity of CVD risk. The proposed study analyzes the hypothesis that ML/DL can lead to an accurate and early diagnosis of the CVD/stroke risk in ED patients. Our finding suggests that the routine ED patient practice can be amended for ML/DL-based CVD/stroke risk assessment using carotid wall arterial imaging leading to fast, reliable, and accurate CVD/stroke risk stratification.

SUMMARY

We conclude that ML and DL methods are very powerful tools for the characterization of CVD/stroke in patients with varying ED conditions. We anticipate a rapid growth of these tools for early and better CVD/stroke risk management in ED patients.

Applications of artificial intelligence in the diagnosis and prediction of erectile dysfunction: a narrative review

Despite the high prevalence of erectile dysfunction, patients are reluctant to seek medical advice, which leads to low diagnostic rates in clinical practice. Artificial intelligence has been widely applied in the diagnosis of many diseases and may alleviate the situation. However, the applications of artificial intelligence in erectile dysfunction have not been reviewed to date. Therefore, the assistance from artificial intelligence needs to be summarized. In this review, 418 publications before January 10, 2021, regarding artificial intelligence applications in diagnosing and predicting erectile dysfunction, were retrieved from five databases, including PubMed, EMBASE, the Cochrane Library, and two Chinese databases (WANFANG and CNKI). In addition, the reference lists of the included studies or relevant reviews were checked to avoid bias. Finally, 30 articles were reviewed to summarize the current status, merits, and limitations of applying artificial intelligence in diagnosing and predicting erectile dysfunction. The results showed that artificial intelligence contributed to developing novel diagnostic questionnaires, equipment, expert systems, classifiers by images and predictive models. However, most of the included studies were not subjected to external validations, resulting in doubt on the generalizability. In the future, more rigorously designed studies with high-quality datasets for erectile dysfunction are required.

CLASSIFYING MYOPATHY AND NEUROPATHY NEUROMUSCULAR DISEASES USING ARTIFICIAL NEURAL NETWORKS

The aim of this study is to classify myopathy and neuropathy neuromuscular diseases using artificial neural networks. Coefficients were obtained from these EMG signals by applying Fast Fourier Transform (FFT), Autoregressive (AR), and Cepstral spectral analysis methods. Each of these coefficients was used as input data for Multilayer Perceptron (MLP), Radial Basis Function (RBF), and Support Vector Machine (SVM). After these inputs were individually trained in MLP, RBF and SVM classification systems, their classification and test performances were examined. The results revealed that the highest prediction was in SVM classification system, whereas the best analysis method was found to be FFT. The results show that the combination of FFT with SVM topology has provided the area under the ROC curve of 0.953, which is considered within the acceptable range.

Corpus cavernosum electromyography: could it be a parameter to predict ageing?

In this study, we investigated whether electromyography of corpus cavernosum (CC-EMG) results vary with age and whether CC-EMG could be a parameter to predict ageing of cavernous smooth muscle. Recordings of electrical activity of corpus cavernosum (EACC) were retrospectively investigated in 134 patients with erectile dysfunction. Penile colour Doppler ultrasonography and cavernosometry were also performed for all of the patients. The total number and duration of EACC and amplitudes between positive and negative peaks were compared between the flask state for 10 min and after intracavernosal papaverine injection. The mean age of the 47 patients in group 1 was 35.2 ± 6.3 years (range, 23-44), the mean age of the 45 patients in group 2 was 51.1 ± 3.1 years (range, 45-56) and the mean age of the 42 patients in group 3 was 61.8 ± 4.6 years (range, 57-77). Total IIEF-5 score was 7.6 ± 2.1 in group 1, 7.9 ± 2.4 in group 2 and 7.9 ± 2.1 in group 3. There were no statistically significant differences among the groups regarding electrical potential frequencies, durations and amplitudes of electromyographic recordings.

CONCLUSION

We do not think that CC-EMG findings could be used efficiently as a predictor of ageing.

Classification of EMG signals using neuro-fuzzy system and diagnosis of neuromuscular diseases

This work investigates the performance of neuro-fuzzy system for analyzing and classifying EMG signals recorded from normal, neuropathy, and myopathy subjects. EMG signals were obtained from 177 subjects, 60 of them had suffered from neuropathy disorder, 60 of them had suffered from myopathy disorder, and rest of them had been normal. Coefficients that were obtained from the EMG signals using Autoregressive (AR) analysis was applied to neuro-fuzzy system. The classification performance of the feature sets was investigated for three classes.

ELECTROCAVERNOSOGRAM IN ERECTILE DYSFUNCTION: A DIAGNOSTIC TOOL

Corpora cavernosa (CC) evoke electric waves that appear to be of diagnostic significance in evaluation of erectile dysfunction (ED). We investigated the hypothesis that electrocavernosography (ECG) exhibits different patterns in the various types of ED: neurogenic, vasculogenic, and psychogenic. Electrocavernosography was performed in the flaccid phase in 16 neurogenic, 28 vasculogenic (15 arteriogenic, 13 venogenic), and 24 psychogenic patients with ED, and in 15 healthy volunteers (controls). Two needle electrodes were introduced into the CC and the EMG activity was recorded in each of the 2 CCs of the same subject. Two 20 minute recording sessions were performed for each subject. The controls recorded slow waves (SWs) with regular rhythm and identical frequency, amplitude and conduction velocity from the 2 electrodes of the same subject. Random action potentials (APs) were superimposed on or followed the SWs. The ECG in the neurogenic ED recorded no waves in 14/16 patients and occasional irregular waves in 2. The SWs of the arteriogenic ED had irregular rhythm and variable and low parameters compared to those of the controls. The ECG of the patients with venogenic ED was similar to that of the controls, while the ECG of the psychogenic ED exhibited SWs with irregular rhythm and higher parameters than the controls. The study has revealed various ECG patterns in ED: "silent" in neurogenic. "bradyarrhythmic" in arteriogenic, "normal" in venogenic, and "overactive" in psychogenic ED. We suggest that electrocavernosography has the potential to function as an investigative tool in diagnosing the type of ED provided further studies are performed to verify the described findings.

Study of the response of the penile corporal tissue and cavernosus muscles to micturition

BACKGROUND

The reaction of the corpora cavernosa (CC), the corpus spongiosum (CS), the bulbocavernosus (BCM) and ischiocavernosus (ICM) muscles to passage of urine through the urethra during micturition is not known. We investigated the hypothesis that the passage of urine through the urethra stimulates the corporal tissue and cavernosus muscles.

METHODS

In 30 healthy men (mean age 42.8 +/- 11.7 years), the electromyographic activity (EMG) of the CC, CS, BCM, and ICM were recorded before and during micturition, and on interruption of and straining during micturition. These tests were repeated after individual anesthetization of urethra, corporal tissue, and cavernosus muscles.

RESULTS

During micturition, the slow wave variables (frequency, amplitude, conduction velocity) of the CC and CS decreased while the motor unit action potentials of the BCM and ICM increased; these EMG changes were mild and returned to the basal values on interruption or termination of micturition. Micturition after individual anesthetization of urethra, corporal tissue and cavernosal muscles did not effect significant EMG changes in these structures, while saline administration produced changes similar to those occurring before saline administration.

CONCLUSION

The decrease of sinusoidal and increase of cavernosus muscles' EMG activity during micturition apparently denotes sinusoidal relaxation and cavernosus muscles contraction. Sinusoidal muscle relaxation and cavernosus muscles contraction upon micturition are suggested to be mediated through a 'urethro-corporocavernosal reflex'. These sinusoidal and cavernosus muscle changes appear to produce a mild degree of penile tumescence and stretch which might assist in urinary flow during micturition.

Application of correlation techniques in the analysis of corpus cavernosum electromyographic signals

AIM

To establish an objective, easy-to-use and comprehensive method to analyze corpus cavernosum electromyographic signals (CC-potentials).

METHODS

CC-potentials were recorded during flaccidity in 23 young healthy volunteers, with surface electrodes placed on the penile shaft bilaterally. Based on the correlation function of Matlab software, an application program for the analysis of CC-potentials was developed. Individual CC-potentials and their autocorrelation function were evaluated, yielding parameters amplitude (A), duration (D), and dominant frequency (DF). The cross-correlation function of both longitudinal and bilateral pairs of adjacent electrodes was calculated to assess the similarity and mutual delay of CC-potentials recorded simultaneously from different parts of the CC. The parameters derived were squared maximum cross-correlation coefficient (Rmax) and delay (tau). Based on the absolute value of tau and the corresponding inter-electrode distance, propagation velocity (PV) was calculated.

RESULTS

The values of the parameters were determined automatically. No significant difference related to the locations of the electrodes for parameters A, D, and DF was detected. The cross-correlation showed that both longitudinal and bilateral CC-potential pairs had highly similar waveforms (the absolute values of Rmax were 0.80 +/- 0.05 and 0.87 +/- 0.06, respectively). PV of longitudinal pairs was estimated as 6.15 +/- 3.98 cm/s.

CONCLUSION

The application program for correlation analysis of CC-potentials is a comprehensive and versatile method to analyze corpus cavernosum electromyographic recordings. Its objectiveness makes multi-center application possible.

Electrophysiologic Activity of the Tunica Albuginea and Corpora Cavernosa: Possible Role of Tunica Albuginea in the Erectile Mechanism

INTRODUCTION

It is claimed that the tunica albuginea (TA) shares in the erectile mechanism by compressing the emissary veins passing through it. However, the TA does not contain smooth muscle fibers.

AIM

We investigated the hypothesis that TA lacks a contractile activity on the emissary veins passing through it.

METHODS

Fourteen healthy male volunteers (mean age 35.2 +/- 4.3 years) were studied. The electromyographic (EMG) activity of the TA and corpora cavernosa (CC) was individually recorded in the flaccid and erectile phases by EMG needle electrodes. Recording was performed in the upper, middle, and lower third of the TA and CC on one and then on the contralateral side.

MAIN OUTCOME MEASURES

The TA lacks a contractile activity on the emissary veins passing through it.

RESULTS

The EMG of the CC in the flaccid phase recorded regular slow waves and random action potentials. The wave variables in the erectile phase exhibited a significant decrease (P < 0.01) compared with the variables in the flaccid phase of the same subject. The TA EMG showed no electric waves in the flaccid or erectile phases. These recordings were similar from the upper-, middle-, and lower-third of the penis, and were reproducible from the contralateral CC.

CONCLUSIONS

Electric waves were recorded from the CC in the flaccid phase; wave variables decreased at erection. In contrast, the TA showed no electric waves in the flaccid or erectile phases. It appears that the TA acts as a CC covering sheet which expands passively at erection, and shares in compressing the subtunical venular plexus between it and the tumescent CC.

Study of interstitial cells in the penis: human study

INTRODUCTION

Specialized pacemaker cells, similar to the interstitial cells of Cajal (ICC) of the gut, have been detected in the urinary organs and are thought to pace their motile activity.

AIM

We investigated the hypothesis that such cells could also exist in the corpora cavernosa (CC) of the human penis.

METHODS

During the treatment of Peyronie's disease in 11 subjects (age 42.6 +/- 3.2 SD years), 3 x 3 mm strips were excised from each of the two CC and subjected to C-kit immunohistochemistry. Controls for the specificity of the antisera consisted of incubation of the tissue with normal rabbit serum substituted for the primary antiserum.

MAIN OUTCOME MEASURES

Interstitial cells similar to ICC could exist in the CC based on C-kit immunohistochemistry.

RESULTS

C-kit positive branched interstitial cells were detected in the CC. They were clearly distinguishable from the smooth muscle cells that were C-kit negative and non-branched. Although the mast cells were C-kit positive, they had a smooth body surface.

CONCLUSIONS

Interstitial cells have been identified in the CC. They are similar to the ICC and may be responsible for initiating the slow waves recorded from the smooth muscle cells and for controlling their activity. We assume that a deficiency or absence of these cells may affect the erectile function of the patient. Further studies are needed to explore the role of these cells in erection.

Interstitial cells of Cajal in erectile dysfunction

The corpora cavernosa (CC) evokes electric activity. Slow waves (SWs) appear to originate from interstitial cells of Cajal (ICCs), which seem to control the activity of the smooth muscle cells (SMC). The ICCs were demonstrated to exist in the CC. We investigated the hypothesis that the ICC distribution differs with each of the various ED types. The study comprised 62 men with ED: 16 neurogenic (NGED), 15 arteriogenic (AGED), 11 venogenic (VGED) and 22 psychogenic (PGED). 15 volunteers with normal erections acted as controls. The patients underwent a complete diagnostic evaluation. A biopsy of 3 x 3 mm from the CC was subjected to C-kit immunohistochemistry examination. Specificity control of the antisera consisted of incubation of the tissue with normal rabbit serum substituted for the primary antiserum. C-kit positive stellate-appearing cells resembling those of ICC were detected in the controls. The branches were either laterally located (multipolar) or lying at each pole (bipolar). They were distinguishable from the SMC, which were C-kit negative. ICC were detected in all specimens from patients with NGED and VGED, absent in 13/15 with AGED and scanty in PGED. ICC distribution was different in the various types of ED. It is suggested that this distribution interferes with SW discharge and the control of SMC activity with a resulting ED.

The hypoactive corpora cavernosa with degenerative erectile dysfunction: a new syndrome

BACKGROUND

In a group of 22 patients with erectile dysfunction, vasculogenic, neurogenic, endocrinologic or psychogenic investigations failed to find a cause for their erectile dysfunction. The electro-cavernosograms of these patients recorded a diminished activity. We investigated the hypothesis that diminished corpus cavernosum electromyography activity was the cause of erectile dysfunction in these patients.

METHODS

The study comprised the above mentioned 22 patients (study group, 43.8 +/- 5.9 SD years) and 15 healthy volunteers (control group, 41.8 +/- 5.1 SD years). The electro-cavernosograms were recorded in the flaccid, erectile and detumescent phases by 2 electrodes inserted into the corpus cavernosum.

RESULTS

The electro-cavernosogram of the healthy volunteers registered in the flaccid phase regular slow waves and random action potentials. The wave variables declined significantly in the erectile phase (p < 0.01). In the study group, the slow wave variables in the flaccid phase exhibited a significant decrease (p < 0.05) compared to the healthy volunteers, and the rhythm was irregular. Erection did not occur with sildenafil administration or intracavernosal papaverine injection, and penile implant was performed. Biopsy examination showed degenerated muscle fibers, and fragmented collagen and elastic fibers with areas of fibrosis.

CONCLUSION

A novel concept of the cause of erectile dysfunction was presented. Corpora cavernosa showed degenerative changes on histopathologic examination and exhibited diminished electromyography activity. They did not respond to sildenafil administration or intracavernosal papaverine injection. Penile implants were the only treatment. The condition is given the name 'hypoactive corpus cavernosum'. The cause of corpus cavernosum degenerative changes needs further study.

Effect of neonatal circumcision on penile neurologic sensation

OBJECTIVES

To evaluate penile sensory thresholds in neonatally circumcised and uncircumcised men.

METHODS

We evaluated 125 patients, 62 uncircumcised men and 63 neonatally circumcised men. All patients completed the Erectile Function domain of the International Index of Erectile Function questionnaire. Of the 125 patients, 29 (International Index of Erectile Function score of between 25 and 30) were placed in the functional group, and 96 in the dysfunctional group. The patients were tested on the dorsal midline glans of the penis (foreskin retracted). Quantitative somatosensory testing was performed and included vibration, pressure, spatial perception, and warm and cold thermal thresholds.

RESULTS

In the functional group, t-test analysis demonstrated a significant (P <0.001) difference, with worse vibration and better pressure sensation for uncircumcised men. When controlling for age, hypertension, and diabetes, all t-test significance was lost. In the dysfunctional group, circumcised men (49 +/- 16 years) were significantly younger (P <0.01) than uncircumcised men (56 +/- 13 years). For the dysfunctional group, t-test analysis also demonstrated worse vibration sensation for uncircumcised men (P <0.01). Again, when controlling for age, hypertension, and diabetes, all t-test significance was lost.

CONCLUSIONS

We present a comparative analysis of uncircumcised and circumcised men using a battery of quantitative somatosensory tests that evaluate the spectrum of small to large axon nerve fiber function. Our study controlled for factors, including age, erectile function status, diabetes, and hypertension, that have been shown to alter neurologic testing. In our study of neonatally circumcised men, we demonstrated that circumcision status does not significantly alter the quantitative somatosensory testing results at the glans penis.

TRANSCUTANEOUS ELECTROCAVERNOSOGRAPHY: A TOOL FOR RECORDING THE ELECTROMYOGRAPHIC ACTIVITY OF THE CORPORA CAVERNOSA

PURPOSE

The electric activity of the corpora cavernosa (CC) is recorded by needle electrodes introduced into the CC. We investigated the hypothesis that transcutaneous electrocavernosography (ECG) would register electric waves similar to those recorded by the needle ECG but noninvasively.

MATERIALS AND METHODS

The ECG was recorded transcutaneously in 35 healthy volunteers (mean age 37.6 +/- 4.8 SD years). Two silver-silver chloride electrodes were applied on the dorsum of the penis over 1 of the CC. A reference electrode was applied to the thigh. Intracavernosal ECG using 2 needle electrodes introduced into the CC was performed in the same subjects. At least two 20 minutes sessions were recorded for each subject.

RESULTS

Slow waves (SWs) were registered transcutaneously. The waves from the 2 electrodes in each individual had the same frequency, amplitude and conduction velocity. They had a regular rhythm and were reproducible. The SWs were followed or superimposed by action potentials which occurred randomly. The transcutaneously recorded SWs were confirmed by the intracavernous route. Both routes had similar ECG recordings.

CONCLUSIONS

The study demonstrated that the transcutaneous ECG recorded electric waves similar to those registered by the intracavernosal route. The transcutaneous ECG is simple, easy, non-invasive, and may be included as an investigative tool in the diagnosis of erectile dysfunction.

Overactive corpus cavernosum: a novel cause of erectile dysfunction

Our recording of the electromyographic (EMG) activity of the corpus cavernosum (CC) in 59 patients with erectile dysfunction (ED) revealed 18 patients who had elevated electric activity, which presumably points to heightened tone of the CC smooth muscles. We investigated the hypothesis that this elevated EMG activity and muscular tone of the CC could be the cause of ED. The study comprised the said 18 subjects with the hypertonic CC muscles as study group (42.6 +/- 5.3 SD years), 15 healthy volunteers (41.8 +/- 5.1 SD years) and 15 patients (41.6 +/- 5.5 SD years) with ED who had not recorded elevated tone of the CC muscles as control group. The EMG activity was registered in the flaccid, erectile and detumescent phases by two electrodes inserted into the CC. Electrocavernosography (ECG) of healthy volunteers recorded in the flaccid phase showed regular slow waves (SW) and random action potentials (APs). The wave variables declined significantly in the erection phase (P < 0.01). In the study group, the SW variables in the flaccid phase increased significantly (P < 0.05) compared with the healthy volunteers and the rhythm was irregular. Erection did not occur with sildenafil but with intracavernosal injection of papaverine, which led to decline of the SW variables (P < 0.05). The control ED group exhibited in the flaccid phase diminished SW variables (P < 0.05) compared with the healthy volunteers. On erection with sildenafil administration, the SW variables showed significant reduction (P < 0.05). CC hypertonicity or 'overactive CC' was identified as a possible cause of ED. An elevated EMG activity of the CC muscle fibres in the flaccid phase presumably denotes hypertonicity of these fibres and their failure to relax to effect erection. The cause of elevated CCEMG activity and presumed muscle hypertonicity is unknown and could be functional or organic. Erection was produced by intracavernosus injection of papaverine and not by sildenafil. This condition of 'overactive CC' should be considered in the diagnosis of ED. However, further studies in the pathogenesis of the condition are warranted.

Investigations in erectile dysfunction

PURPOSE OF REVIEW

This is an update of recent developments in the investigation of erectile dysfunction in the period since March 2002.

RECENT FINDINGS

Three developments in the field of medical sexology redirected the approach towards the investigation of erectile dysfunction. First, the emergence of oral pharmacological therapy; second, the notion that sexual relationship issues have an important impact on the successful outcome of pharmacological therapy; and finally, the concept that erectile dysfunction is often a sequel or even a sentinel of cardiovascular disease. Consequently, the current evaluation of men with erectile dysfunction may be divided into two steps: a basic diagnostic evaluation for the majority of men, and specific diagnostic procedures for a small minority. The basic evaluation is aimed at the identification of the underlying pathological condition and erectile dysfunction-associated risk factors. Such screening may diagnose reversible causes of erectile dysfunction and also unmask medical and psychological conditions that manifest with erectile dysfunction. The basic evaluation consists of a comprehensive medical, sexual and psychosocial history and a physical examination. Patients who have failed first-line treatment or complicated cases qualify for specific diagnostic procedures, traditionally performed by urologists.

SUMMARY

Current research into the investigation of erectile dysfunction emphasizes the notion that erectile dysfunction is often a result of an interplay between medical and psychosexual conditions. Recognition of the underlying conditions and an estimation of their relative contribution to the patient's and his partner's sexual problem are key issues in the current evaluation of the man with erectile dysfunction.

Quantitative somatosensory testing of the penis: optimizing the clinical neurological examination

PURPOSE

Quantitative somatosensory testing, including vibration, pressure, spatial perception and thermal thresholds of the penis, has demonstrated neuropathy in patients with a history of erectile dysfunction of all etiologies. We evaluated which measurement of neurological function of the penis was best at predicting erectile dysfunction and examined the impact of location on the penis for quantitative somatosensory testing measurements.

MATERIALS AND METHODS

A total of 107 patients were evaluated. All patients were required to complete the erectile function domain of the International Index of Erectile Function (IIEF) questionnaire, of whom 24 had no complaints of erectile dysfunction and scored within the "normal" range on the IIEF. Patients were subsequently tested on ventral middle penile shaft, proximal dorsal midline penile shaft and glans penis (with foreskin retracted) for vibration, pressure, spatial perception, and warm and cold thermal thresholds.

RESULTS

Mixed models repeated measures analysis of variance controlling for age, diabetes and hypertension revealed that method of measurement (quantitative somatosensory testing) was predictive of IIEF score (F = 209, df = 4,1315, p <0.001), while site of measurement on the penis was not. To determine the best method of measurement, we used hierarchical regression, which revealed that warm temperature was the best predictor of erectile dysfunction with pseudo R(2) = 0.19, p <0.0007. There was no significant improvement in predicting erectile dysfunction when another test was added. Using 37C and greater as the warm thermal threshold yielded a sensitivity of 88.5%, specificity 70.0% and positive predictive value 85.5%.

CONCLUSIONS

Quantitative somatosensory testing using warm thermal threshold measurements taken at the glans penis can be used alone to assess the neurological status of the penis. Warm thermal thresholds alone offer a quick, noninvasive accurate method of evaluating penile neuropathy in an office setting.

Gender dependent EMGs of runners resolved by time/frequency and principal pattern analysis

A promising approach for the analysis of surface electromyograms is to use wavelets to determine the spectral distribution of the signal intensity at any time. The authors have recently proposed using non-linearly scaled wavelets to obtain intensity patterns, which reflect the spectral distribution at any given time point. Further analysis of intensity-patterns is greatly facilitated by representing them as linear combinations of a base set of principal-patterns. The weight with which each principal-pattern contributes to the intensity-pattern can be represented on a set of orthogonal axes that span a previously introduced pattern space. The purpose of the present study was to show how to use pattern space to discriminate and classify male and female runners based on the electromyograms of five muscles of the limb. The results showed that there were significant gender specific differences, which allowed more than a 95% correct classification of the subjects as males or females. Classification was possible irrespective of the shod condition while running. Gender specific differences occurred at well-defined time periods during the movement. Common to both genders was that spectral changes did not parallel the changes in total signal intensity.

The value of corpus cavernosum electromyography in erectile dysfunction: current status and future prospect

In the last decade, several investigators have tried to develop corpus cavernosum electromyography (CC-EMG) as a direct clinical method to evaluate the state of the penile autonomic innervation and the cavernous smooth muscle. Both basic and clinical studies have shown promising results. However, its application as a diagnostic tool with clinical relevance was hindered by insufficient knowledge of cavernous smooth muscle electrophysiology, lack of standardization, technical and practical difficulties and problems in the interpretation of the results. Recently, the European Commission created the so-called COST Action B18 (corpus cavernosum EMG in erectile dysfunction), aiming to strengthen the coordination of the European research groups and give the development of CC-EMG a new impetus. This review presents an overview of the physiological background, the current status of CC-EMG, and discusses possibilities for further developments.

The neuropathy of erectile dysfunction

These studies were intended to explore the relationship between autonomic neuropathy and erectile dysfunction (ED). Sensory thresholds reflecting the integrity of both large diameter, myelinated neurons (ie pressure, touch, vibration) and small diameter axons (ie hot and cold thermal sensation) were determined on the penis and finger. Data were compared across subjects with and without ED, controlling for age, hypertension and diabetes. The correlation of specific thresholds scores and IIEF values were also examined. Seventy-three patients who visited the academic urology clinics at Montefiore hospital were evaluated. All patients were required to complete the erectile function domain of the International Index of Erectile Function (IIEF) questionnaire: 20 subjects had no complaints of ED and scored within the 'normal' range on the IIEF. Patients were subsequently tested on their index finger and glans penis for vibration (Biothesiometer), pressure (Semmes-Weinstein monofilaments), spatial perception (Tactile Circumferential Discriminator), and warm and cold thermal thresholds (Physitemp NTE-2). Sensation of the glans penis, as defined by the examined sensory thresholds, was significantly diminished in patients with ED and these differences remained significant when controlling for age, diabetes and hypertension. In contrast, thresholds on the index finger were equivalent in the ED and non-ED groups. Threshold and IIEF scores were highly correlated, consistent with an association between diminished sensation and decreasing IIEF score (worse erectile functioning). These relations also remained significant when controlling for age, diabetes and hypertension. The findings demonstrate dysfunction of large and small diameter nerve fibers in patients with ED of all etiologies. Further, the neurophysiologic measures validate the use of the IIEF as an index of ED, as objective findings of sensory neuropathy were highly correlated with worse IIEF scores. The sensory threshold methods utilized represent novel, non-invasive and relatively simple procedures, which can be used in a longitudinal fashion to assess a patient's neurological response to therapies.

Neurogenic erectile dysfunction

Penile erection is a neurovascular event modulated by psyche and hormones. Erectile dysfunction (ED) has been classified as psychogenic, arteriogenic, neurogenic, endocrinologic, and cavernosal, based on the organs that are involved in penile erection. Among these types, neurogenic ED may be the most common, probably because a deficiency of neurotransmitters is the final common pathway in many diseases and conditions. This review discusses the physiology, pathophysiology, diagnosis, and treatment of erectile function and dysfunction, as well as strategies for future research.

Neurologic erectile dysfunction

Neurologic erectile dysfunction presents a diagnostic and treatment challenge to the internist and urologist. Multiple chronic disease modalities and traumatic etiologies exist. Education regarding these conditions and a detailed and thorough history and office work-up are the best resources for the clinician. Treatment can follow the model of proceeding from the least to most invasive procedure (process of care), taking into account patient and partner satisfaction. Because the psychology of grief and loss may enter into treatment of some neurologic conditions (e.g., erectile dysfunction after radical retropubic prostatectomy, spinal cord injury, or chronic diseases), a whole-patient approach encompassing psychotherapy is warranted.

The role of corpus cavernosum electromyography

Although corpus cavernosum electromyography presents great theoretical appeal as a possible direct clinical measure of penile neurogenic function, it has still not been adopted as a routine diagnostic test in the evaluation of patients with erectile dysfunction. This is because of the considerable technical and interpretative problems associated with the method. This review covers some of the more important research and clinical papers published since its first description in 1989, with a special focus on recent advances in this field.