Central Neural Correlates During Inhibitory Control in Lifelong Premature Ejaculation Patients

The role of acupuncture in treating premature ejaculation and its probable neurobiological mechanism

BACKGROUND

Premature ejaculation (PE) is one of the most common diseases in andrology and leads to serious male sexual dysfunction. Although several targeted oral drug therapies are used to treat PE, they often face challenges related to imprecise targeting and adverse effects. Acupuncture has shown potential in prolonging ejaculation time and improving couples' sexual quality of life. This review aims to summarize the benefits of acupuncture in treating PE and explore its probable neurobiological mechanisms.

RESULTS

The review included eight clinical trials involving 679 patients, of which 294 were treated with acupuncture. Furthermore, this review analyzed acupuncture points, needle retention time, treatment duration, and their probable neurobiological mechanisms. The proposed mechanisms include stimulating the frontal functional lobe, inhibiting spinal cord neural pathways, regulating serotonin levels, enhancing 5-hydroxytryptamine receptor IB excitability, reducing penile sensitivity, and modulating hormone levels.

CONCLUSIONS

Acupuncture is a viable alternative or complementary therapy for PE, and neurobiological mechanisms appear to play a key role, but further experimental validation is needed.

Recommendations for the diagnosis and evaluation of premature ejaculation

OBJECTIVES

The Association Interdisciplinaire Post-Universitaire de Sexologie (AIUS) has brought together a panel of experts to draw up French recommendations for the management of premature ejaculation. This article presents the recommendations for the diagnosis and evaluation of premature ejaculation.

METHODS

Systematic review of the literature between 01/1995 and 02/2022. Using the method of recommendations for clinical practice (RPC).

RESULTS

We recommend using the SIAMS definition for everyday clinical practice. PE is defined as: (i) a persistent and recurrent subjective perception of loss of control (management) of the ejaculatory mechanism in the presence of appropriate erotic stimuli; (ii) subjective, PE-related distress induced in the patient and sexual dissatisfaction or PE-related anorgamy in the partner; (iii) a short intravaginal ejaculatory latency time, whether subjectively perceived by the patient and the partner or objectively measured as less than 180seconds (generally). We suggest that the same definition be applied to practices other than vaginal penetration, such as masturbation, oral or anal intercourse, as well as to non-heterosexual contexts. We suggest using information reported by the patient, possibly supplemented by assessment tests/questionnaires (IPE, PEP, PEDT). We recommend investigating the presence of other sexual dysfunctions, in particular erectile dysfunction (ED), as well as any sexual dysfunctions of partners. We recommend taking a medical and psychosexological history, and carrying out a targeted physical examination in patients complaining of PE.

CONCLUSION

These recommendations should help to improve the management of PE.

Altered regional brain activity and functional connectivity in primary intravaginal anejaculation patients revealed by resting-state fMRI

ABSTRACT

Ejaculation is regulated by the central nervous system. However, the central pathophysiology of primary intravaginal anejaculation (PIAJ) is unclear. The present study aimed to examine the changes in regional brain activity and functional connectivity underlying PIAJ. A total of 20 PIAJ patients and 16 healthy controls (HCs) were enrolled from September 2020 to September 2022 in the Department of Andrology, Nanjing Drum Tower Hospital (Nanjing, China). Magnetic resonance imaging data were acquired from all participants and then were preprocessed. The measures of fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), and functional connectivity (FC) were calculated and compared between the groups. PIAJ patients showed increased fALFF values in the left precuneus compared with HCs. Additionally, PIAJ patients showed increased ReHo values in the left precuneus, left postcentral gyrus, left superior occipital gyrus, left calcarine fissure, right precuneus, and right middle temporal gyrus, and decreased ReHo values in the left inferior parietal gyrus, compared with HCs. Finally, brain regions with altered fALFF and ReHo values in PIAJ patients showed increased FC with widespread cortical regions, which included the frontal, parietal, temporal, and occipital regions, compared with HCs. In conclusion, increased regional brain activity in the parietal, temporal, and occipital regions, and increased FC between these brain regions, may be associated with PIAJ occurrence.

Decreased grey matter volume in dorsolateral prefrontal cortex and thalamus accompanied by compensatory increases in middle cingulate gyrus of premature ejaculation patients

INTRODUCTION

The prefrontal-cingulate-thalamic areas are associated with ejaculation control. Functional abnormalities of these areas and decreased grey matter volume (GMV) in the subcortical areas have been confirmed in premature ejaculation (PE) patients. However, no study has explored the corresponding GMV changes in the prefrontal-cingulate-thalamic areas, which are considered as the important basis for functional abnormalities. This study aimed to investigated whether PE patients exhibited impaired GMV in the brain, especially the prefrontal-cingulate-thalamic areas, and whether these structural deficits were associated with declined ejaculatory control.

METHODS

T1-weighted structural magnetic resonance imaging (MRI) data were acquired from 50 lifelong PE patients and 50 age-, and education-matched healthy controls (HCs). The PE diagnostic tool (PEDT) was applied to assess the subjective symptoms of PE. Based on the method of voxel-based morphometry (VBM), GMV were measured and compared between groups. In addition, the correlations between GMV of brain regions showed differences between groups and PEDT scores were evaluated in the patient group.

RESULTS

PE patients showed decreased GMV in the right dorsolateral superior frontal gyrus (clusters = 13, peak T-values = -4.30) and left thalamus (clusters = 47, T = -4.33), and increased GMV in the left middle cingulate gyrus (clusters = 12, T = 4.02) when compared with HCs. In the patient group, GMV of the left thalamus were negatively associated with PEDT scores (r = -0.35; P = 0.01). Receiver operating characteristic (ROC) analysis showed that GMV of the right dorsolateral superior frontal gyrus (AUC = 0.71, P < 0.01, sensitivity = 60%, specificity = 78%), left thalamus (AUC = 0.72, P < 0.01, sensitivity = 92%, specificity = 46%) and middle cingulate gyrus (AUC = 0.69, P < 0.01, sensitivity = 50%, specificity = 90%), and the combined model (AUC = 0.84, P < 0.01, sensitivity = 78%, specificity = 80%) all had the ability to distinguish PE patients from HCs.

CONCLUSION

Disturbances in GMV were revealed in the prefrontal-cingulate-thalamic areas of PE patients. The findings implied that decreased GMV in the dorsolateral prefrontal cortex and thalamus might be associated with the central pathological neural mechanism underlying the declined ejaculatory control while increased GMV in the middle cingulate gyrus might be the compensatory mechanism underlying PE.

Abnormal cortical surface-based spontaneous and functional connectivity in the whole brain in lifelong premature ejaculation patients

Recent research has highlighted structural and functional abnormalities in the cerebral cortex of patients with premature ejaculation (PE). These anomalies could play a pivotal role in the physiological mechanisms underlying PE. This study leveraged functional magnetic resonance imaging (fMRI), a noninvasive technique, to explore these neural mechanisms. We conducted resting-state fMRI scans on 36 PE patients and 22 healthy controls (HC), and collected data on Premature Ejaculation Diagnostic Tool (PEDT) scores and intravaginal ejaculation latency time (IELT). Employing a surface-based regional homogeneity (ReHo) approach, we analyzed local neural synchronous spontaneous activity, diverging from previous studies that utilized a volume-based ReHo method. Areas with significant ReHo differences between PE and HC groups underwent surface-based functional connectivity (FC) analysis. Significant discrepancies in ReHo and FC across the cortical surface were observed in the PE cohort. Notably, PE patients exhibited decreased ReHo in the left triangular inferior frontal gyrus and enhanced ReHo in the right middle frontal gyrus. The latter showed heightened connectivity with the left lingual gyrus and the right orbital superior frontal gyrus. Furthermore, a correlation between ReHo and FC values with PEDT scores and IELT was found in the PE group. Our findings, derived from surface-based fMRI data, underscore specific brain regions linked to the neurobiological underpinnings of PE.

Changes of insular function in lifelong premature ejaculation patients before and after SSRI administration

OBJECTIVE

Lifelong premature ejaculation (PE) is regarded as one of the most common male sexual dysfunction. We aimed to detect whether insula-related brain functional networks are altered in lifelong PE patients and whether such alterations are "normalised" after selective serotonin reuptake inhibitors (SSRI) administration.

METHODS

Twenty-three drug-naive lifelong PE patients and 30 healthy controls (HC) were recruited in current study. All subjects underwent resting-state functional magnetic resonance imaging (fMRI) scan at first. One hour after dapoxetine administration, all patients underwent fMRI scanning again. The degree centrality (DC), amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) analysis, and ROI-based functional connectivity (FC) analysis were applied to calculate the abnormalities in insula-related functions among three groups.

RESULTS

Compared to HC group, PE patients at baseline showed significantly altered DC, ALFF, and ReHo value of the bilateral insula, which subsequently showed a "normalised" trend after dapoxetine administration. Additionally, compared to HC group, PE patients at baseline showed significantly decreased FC between insula and precentral gyrus, inferior frontal gyrus, middle/inferior temporal gyrus, and caudate, while patients after dapoxetine administration showed increased insula-related FC in anterior cingulate cortex and decreased FC in thalamus and middle/inferior temporal gyrus. The main effects of dapoxetine were located in precentral gyrus, inferior frontal gyrus, caudate, and limbic system.

CONCLUSIONS

Our findings report altered brain mechanism of insula in lifelong PE patients and also indicate that dapoxetine can "normalise" the abnormal function of the insula to certain extent in lifelong PE patients.

Potential biomarkers for distinguishing primary from acquired premature ejaculation: A diffusion tensor imaging based network study

Introduction

Premature ejaculation (PE) is classified as primary and acquired and may be facilitated by different pathophysiology. Brain plays an important role in PE, however, differences in the central neuropathological mechanisms among subtypes of PE are unknown.

Materials and methods

We acquired diffusion tensor imaging (DTI) data from 44 healthy controls (HC) and 47 PE patients (24 primary PE and 23 acquired PE). Then, the whole-brain white matter (WM) structural networks were constructed and between-group differences of nodal segregative parameters were identified by the method of graph theoretical analysis. Moreover, receiver operating characteristic (ROC) curves were performed to determine the suitability of the altered parameters as potential neuroimaging biomarkers for distinguishing primary PE from acquired PE.

Results

PE patients showed significantly increased clustering coefficient C(i) in the left inferior frontal gyrus (triangular part) (IFGtriang.L) and increased local efficiency E_loc(i) in the left precental gyrus (PreCG.L) and IFGtriang.L when compared with HC. Compared to HC, primary PE patients had increased C(i) and E_loc(i) in IFGtriang.L and the left amygdala (AMYG.L) while acquired PE patients had increased C(i) and E_loc(i) in IFGtriang.L, and decreased C(i) and E_loc(i) in AMYG.L. Compared to acquired PE, primary PE patients had increased C(i) and E_loc(i) in AMYG.L. Moreover, ROC analysis revealed that PreCG.L, IFGtriang.L and AMYG.L might be helpful for distinguishing different subtypes of PE from HC (PE from HC: sensitivity, 61.70–78.72%; specificity, 56.82–77.27%; primary PE from HC: sensitivity, 66.67–87.50%; specificity, 52.27–77.27%; acquired PE from HC: sensitivity, 34.78–86.96%; specificity, 54.55–100%) while AMYG.L might be helpful for distinguishing primary PE from acquired PE (sensitivity, 83.33–91.70%; specificity, 69.57–73.90%).

Conclusion

These findings improved our understanding of the pathophysiological processes that occurred in patients with ejaculatory dysfunction and suggested that the abnormal segregation of left amygdala might serve as a useful marker to help clinicians distinguish patients with primary PE from those with acquired PE.

Convergent and Divergent Structural Connectivity of Brain White Matter Network Between Patients With Erectile Dysfunction and Premature Ejaculation: A Graph Theory Analysis Study

Background

Sexual dysfunction, namely, erectile dysfunction (ED) and premature ejaculation (PE), has been found to be associated with abnormal structural connectivity in the brain. Previous studies have mainly focused on a single disorder, however, convergent and divergent structural connectivity patterns of the brain network between ED and PE remain poorly understood.

Methods

T1-weighted structural data and diffusion tensor imaging data of 28 patients with psychological ED, 28 patients with lifelong PE (LPE), and 28 healthy controls (HCs) were obtained to map the white matter (WM) brain networks. Then, the graph-theoretical method was applied to investigate the differences of network properties (small-world measures) of the WM network between patients with ED and LPE. Furthermore, nodal segregative and integrative parameters (nodal clustering coefficient and characteristic path length) were also explored between these patients.

Results

Small-world architecture of the brain networks were identified for both psychological ED and LPE groups. However, patients with ED exhibited increased average characteristic path length of the brain network when compared with patients with LPE and HCs. No significant difference was found in the average characteristic path length between patients with LPE and HCs. Moreover, increased nodal characteristic path length was found in the right middle frontal gyrus (orbital part) of patients with ED and LPE when compared with HCs. In addition, patients with ED had increased nodal characteristic path length in the right middle frontal gyrus (orbital part) when compared with patients with LPE.

Conclusion

Together, our results demonstrated that decreased integration of the right middle frontal gyrus (orbital part) might be a convergent neuropathological basis for both psychological ED and LPE. In addition, patients with ED also exhibited decreased integration in the whole WM brain network, which was not found in patients with LPE. Therefore, altered integration of the whole brain network might be the divergent structural connectivity patterns for psychological ED and LPE.

Functional Connectivity of Nucleus Accumbens Is Associated with Lifelong Premature Ejaculation in Male Adults : A Resting-state fMRI Study

PURPOSE

Ejaculation represents a crucial component of sexual behavior in men, which is involved in reward functions of certain brain areas including the nucleus accumbens (NAcc). Lifelong premature ejaculation (PE) is one of the most prevalent sexual dysfunctions in men. It is suggested to be related to abnormal brain function. This study aimed to explore changes of the functional connectivity patterns of NAcc and possible correlations of the neuroimaging abnormalities with clinical features in lifelong PE patients.

METHODS

The sample consisted with 42 lifelong PE patients and 30 healthy controls. All participants underwent functional magnetic resonance imaging scans and clinical symptoms. The functional connectivity (FC) approach was applied to investigate differences of NAcc-seed intrinsic connectivity between two groups and correlation analysis was used to access possible relationships between the imaging findings and clinical features, such as premature ejaculation diagnostic tool (PEDT) or intravaginal ejaculatory latency time (IELT).

RESULTS

Results showed that lifelong PE patients had decreased FC between the NAcc and thalamus, superior temporal pole, superior temporal cortex (STC), inferior frontal gyrus (IFG), orbitofrontal cortex, caudate and putamen. A significantly negative correlation between the PEDT score and NAcc-STC connectivity (r = -0.46) was found in lifelong PE patients, while IELT score positively correlated with the NAcc-IFG connectivity (r = 0.48) and NAcc-thalamus connectivity (r = 0.46).

CONCLUSION

The findings may facilitate a more sophisticated understanding of neural mechanisms of lifelong PE, particularly associated with the NAcc-related intrinsic connectivity during the resting state.

Thalamocortical Dysconnectivity In Lifelong Premature Ejaculation: A Functional MRI Study

OBJECTIVES

To detect seed-based functional connectivity (FC) between various cortical sub-regions and the thalamus in lifelong premature ejaculation (LPE) patients and explore whether specific thalamocortical networks are significantly altered in PE patients compared to healthy controls (HCs) METHODS: Fifty non-medicated LPE patients and 40 age-matched HCs underwent a resting-state functional MRI. FC was adopted to identify specific thalamocortical connectivity between the thalamus and 6 cortical regions of interest (i.e., the motor cortex/supplementary motor, the prefrontal cortex, the temporal lobe, the posterior parietal cortex, the somatosensory cortex and the occipital lobe). In LPE patients, regression analysis was subsequently conducted to assess relationships of thalamocortical connectivity with the Premature Ejaculation Diagnostic Tool (PEDT) score and the Intravaginal Ejaculatory Latency Time (IELT).

RESULTS

LPE patients had significantly decreased FC between the motor cortex and bilateral ventral thalamus, between the prefrontal cortex and left dorsomedial thalamus, as well as between the temporal cortex and bilateral ventromedial thalamus. In LPE patients, PEDT score was significantly positively associated with the thalamus-posterior parietal cortex FC, and negatively associated with the thalamus-temporal cortex FC, while IELT was positively associated with the thalamus-temporal cortex and thalamus-motor cortex FC.

CONCLUSION

These results enrich the imaging evidence for the understanding of the neurobiological mechanisms and/or consequences of LPE.

Reconfiguration of Dynamic Functional Connectivity States in Patients With Lifelong Premature Ejaculation

Purpose: Neuroimaging has demonstrated altered static functional connectivity in patients with premature ejaculation (PE), while studies examining dynamic changes in spontaneous brain activity in PE patients are still lacking. We aimed to explore the reconfiguration of dynamic functional connectivity (DFC) states in lifelong PE (LPE) patients and to distinguish LPE patients from normal controls (NCs) using a machine learning method based on DFC state features. Methods: Thirty-six LPE patients and 23 NCs were recruited. Resting-state functional magnetic resonance imaging (fMRI) data, the clinical rating scores on the Chinese Index of PE (CIPE), and intravaginal ejaculatory latency time (IELT) were collected from each participant. DFC was calculated by the sliding window approach. Finally, the Lagrangian support vector machine (LSVM) classifier was applied to distinguish LPE patients from NCs using the DFC parameters. Two DFC state metrics (reoccurrence times and transition frequencies) were introduced and we assessed the correlations between DFC state metrics and clinical variables, and the accuracy, sensitivity, and specificity of the LSVM classifier. Results: By k-means clustering, four distinct DFC states were identified. The LPE patients showed an increase in the reoccurrence times for state 3 (p < 0.05, Bonferroni corrected) but a decrease for state 1 (p < 0.05, Bonferroni corrected) compared to the NCs. Moreover, the LPE patients had significantly less frequent transitions between state 1 and state 4 (p < 0.05, uncorrected) while more frequent transitions between state 3 and state 4 (p < 0.05, uncorrected) than the NCs. The reoccurrence times and transition frequencies showed significant associations with the CIPE scores and IELTs. The accuracy, sensitivity, and specificity of the LSVM classifier were 90.35, 87.59, and 85.59%, respectively. Conclusion: LPE patients were more inclined to be in DFC states reinforced intra-network and inter-network connection. These features correlated with clinical syndromes and can classify the LPE patients from NCs. Our results of reconfiguration of DFC states may provide novel insights for the understanding of central etiology underlying LPE, indicate neuroimaging biomarkers for the evaluation of clinical severity of LPE.

Is Ejaculation Frequency in Men Related to General and Mental Health? Looking Back and Looking Forward

Despite its relevance for human sexuality, literature on potential effects of ejaculation frequency and masturbation on general and mental health outcomes is sparse. Reasons for this knowledge gap include a general lack of interest, but also methodological challenges and still existing superstition. This paper reconciles literature from various fields to extract relevant information on how ejaculation frequency effects general and mental health outcomes. Culture-bound syndromes have been reported in countries still strictly tabooing or condemning masturbation. Masturbatory guilt describes a phenomenon in individuals experiencing a discrepancy between moral standards and own behavior with respect to masturbation. Abstinence is one aspect under study in the area of fertility treatment. Specific time frames and their respective implications on quality of sperm remain inconclusive. Limited temporal resolution capacities hamper the precise study of brain structures directly activated during ejaculation. The relation between ejaculation frequency and hormonal influences remains poorly understood. Future research that specifically addresses ejaculation frequency and potential mental and general health outcomes is needed. In contrast to extracting knowledge as a byproduct from other studies with a different focus, this enables sound study designs and could provide evidence-based results which could then be further discussed and interpreted.

Abnormal Functional Connectivity Between the Left Medial Superior Frontal Gyrus and Amygdala Underlying Abnormal Emotion and Premature Ejaculation: A Resting State fMRI Study

Introduction

Premature ejaculation (PE) is a common sexual dysfunction and is found to be associated with abnormal emotion. The amygdala plays an important role in the processing of emotion. The process of ejaculation is found to be mediated by the frontal-limbic neural circuits. However, the correlations between PE and emotion are still unclear.

Methods

Resting-state functional magnetic resonance imaging (rs-fMRI) data were acquired in 27 PE patients with stable emotion (SPE), 27 PE patients with abnormal emotion (NPE), and 30 healthy controls (HC). We used rs-fMRI to explore the underlying neural mechanisms in SPE, NPE, and HC by measuring the functional connectivity (FC). Differences of FC values among the three groups were compared when choosing bilateral amygdala as the regions of interest (ROIs). We also explored the correlations between the brain regions showing altered FC values and scores of the premature ejaculation diagnostic tool (PEDT)/Eysenck Personality Inventory about neuroticism (EPQ-N) in the PE group.

Results

When the left amygdala was chosen as the ROI, the SPE group exhibited an increased FC between the left medial superior frontal gyrus (SFGmed) and amygdala compared with the NPE or HC group. When the right amygdala was chosen as the ROI, the NPE group exhibited a decreased FC between the left SFGmed and right amygdala compared with the HC group. In addition, FC values of the left SFGmed had positive correlations with PEDT and negative correlations with EPQ-N scores in the PE group. Moreover, FC values of the left superior temporal gyrus had positive correlations with EPQ-N scores in the PE group.

Conclusion

The increased FC values between the left SFGmed and amygdala could reflect a compensatory cortical control mechanism with the effect of stabilized emotion in the limbic regions of PE patients. Abnormal FC between these brain regions could play a critical role in the physiopathology of PE and could help us in dividing PE into more subtypes.

Increased attentional network activity in premature ejaculation patients with anxiety revealed by resting-state functional magnetic resonance imaging

Psychological account hypothesizes that premature ejaculation (PE) is a learned pattern of rapid ejaculation maintained by anxiety about sexual failure, whereas neuropsychological accounts hypothesizes that PE is the result of dysfunction of central nervous system regulating ejaculatory. However, the central neural mechanism underlying PE patients with anxiety remains unclear. Resting-state functional magnetic resonance imaging (fMRI) data were collected in 20 PE (diagnoses based on PE Guidelines drafted by the International Society for Sexual Medicine [ISSM]) patients with anxiety and 25 matched healthy controls (HCs) from January 2019 to December 2020. The values of fractional amplitude of low-frequency fluctuation (fALFF) were compared between groups. Moreover, the correlations between fALFF and the severity of PE and anxiety of patients were examined. PE patients with anxiety had increased fALFF values in the right inferior frontal gyrus (opercular part) and middle frontal gyrus. In addition, significant positive correlations were found between the scores of PE diagnostic tool (PEDT) and fALFF values of the right inferior frontal gyrus (opercular part), as well as the right middle frontal gyrus. Moreover, fALFF values of the right inferior frontal gyrus (opercular part) and middle frontal gyrus were positively correlated with the scores of self-rating anxiety scale (SAS). Our results suggested that increased attentional network activity might play a critical role in the neural basis of PE patients with anxiety.

Magnetic Resonance Imaging-Based Structural Covariance Changes of the Striatum in Lifelong Premature Ejaculation Patients

BACKGROUND

The striatum has been reported to be implicated in various neurological diseases, including lifelong premature ejaculation (LPE). Altered striatum-related functional connectivity was investigated in LPE patients in previous studies; however, structural abnormalities in the striatum have been less studied in LPE.

PURPOSE

To identify the gray matter volume (GMV) and structural covariance patterns of the striatum between LPE patients and healthy controls (HCs).

STUDY TYPE

Prospective.

SUBJECTS

Forty-three LPE patients and 31 male HCs.

FIELD STRENGTH/SEQUENCE

3.0 T magnetic resonance imaging (MRI) scanner; T1-weighted imaging using a spoiled gradient recalled echo sequence.

ASSESSMENT

Preprocessing of structural MRI data and the striatum-seeded GMV computation were conducted using SPM12.

STATISTICAL TESTS

Two sample t-test was used to compare differences in GMV of the striatum between patients and HCs. Regions showing altered between-group GMV were considered as seeds for structural covariance analysis in two groups. Additionally, correlations between GMV findings and clinical features were assessed with age and total intracranial volume (TIV) as covariates and with age, TIV, anxiety, and depression scores as covariates in the patient group, P < 0.05 was considered statistically significant.

RESULTS

Compared to HCs, LPE patients had significantly decreased GMV in four regions located in the bilateral caudate and putamen. Distinct striatum-based structural covariance patterns in the two groups were mainly related to the thalamus, amygdala, insula, anterior cingulate cortex, middle cingulate cortex, medial prefrontal cortex, primary motor cortex, and precuneus/cuneus. LPE patients showed that GMV in the bilateral caudate negatively correlated with the premature ejaculation diagnostic tool (PEDT) scores (r = -0.369, r = -0.377, respectively).

DATA CONCLUSION

Our findings indicated that LPE patients had altered GMV and structural covariance patterns in the striatum compared to HCs. The correlations between abnormal GMV and PEDT were also shown in the present findings. These findings may contribute to enhancing the understanding of the pathophysiology of LPE.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 3.

Abnormal degree centrality in lifelong premature ejaculation patients: an fMRI study

Lifelong premature ejaculation (PE) is one of the most prevalent male sexual dysfunctions. It is still not well known about the possible neural mechanisms of lifelong PE. This study tried to investigate the abnormal characteristics of brain functional networks of lifelong PE and to assess relationships of PE-related functional abnormalities with clinical symptoms. Functional magnetic resonance imaging (fMRI) data and clinical symptoms were collected from 45 lifelong PE patients and 37 healthy controls (HCs) since 2016, including disease and sexual life history, intravaginal ejaculatory latency time measured by stopwatch and other scales. The degree centrality (DC) approach were applied to distinguish altered brain functions between the two groups (p < 0.05, false discovery rate corrected). Correlation analysis was then performed to examine relationships between the imaging findings and clinical symptoms (p < 0.05, Bonferroni corrected). Results showed that compared with HCs, lifelong PE patients had increased DC value in the medial prefrontal cortex (mPFC), precuneus and primary somatosensory cortex (SI) as well as decreased DC value in the insula and orbitofrontal cortex. After controlling for anxiety and depression levels, the significant difference in the mPFC was not found. The DC value in the SI positively correlated with premature ejaculation diagnostic tool (PEDT) score in the patients. The present findings indicate that lifelong PE patients have altered DC in brain regions involved in sensation, motivation and inhibitory control processing. Our study may improve our understanding and provide a new sight into the further research of lifelong PE.

Higher inter-hemispheric homotopic connectivity in lifelong premature ejaculation patients: a pilot resting-state fMRI study

Background

Lifelong premature ejaculation (PE) is one common male sexual dysfunction and is implicated in widespread structural and functional abnormalities of bilateral hemispheres. However, whether the inter-hemisphere functional connectivity (FC) of lifelong PE patients was altered still remain unclear.

Methods

Thirty-four lifelong PE patients and 30 healthy controls (HCs) were enrolled in this study and all underwent T1-weighted and resting-state functional MRI (fMRI) scan. The voxel-mirrored homotopic connectivity (VMHC) measure and independent sample t-test were applied to examine the alterations of VMHC values in the patients relative to HCs with the significant threshold at P<0.05, false discovery rates corrected. Correlation analysis was adopted to calculate the relationships between the imaging results and clinical characteristics of patients (P<0.05, Bonferroni corrected). Receiver operating characteristic (ROC) curve analysis was performed to investigate the possible biomarkers for distinguishing the patients from the HCs using the VMHC values of inter-group differences.

Results

The results revealed that compared with HCs, lifelong PE patients had higher VMHC values in the precentral gyrus (PG), primary somatosensory cortex (S1), supplementary motor area (SMA), precuneus, middle temporal cortex (MTC), superior temporal pole (STP), thalamus, caudate and middle cingulate cortex (MCC). Correlation analysis showed that the mean VMHC values in the S1 negatively correlated with intravaginal ejaculation latency time (IELT) in the patient group. Furthermore, the caudate revealed the well classification power from the ROC analysis.

Conclusions

The present study showed the abnormal inter-hemisphere interaction and integration of information involved in ejaculation inhibitory control, sensorimotor mediation and self-reference processing including the thalamus, caudate, MCC, widespread parietal cortex and temporal cortex in lifelong PE patients compared with HCs. Correlation analysis and ROC analysis revealed the importance of S1 and caudate in lifelong PE. Notably, the ROC result of caudate might show the core roles of caudate played in the pathophysiology of lifelong PE.

Smaller volume and altered functional connectivity of the amygdala in patients with lifelong premature ejaculation

OBJECTIVES

To analyze the abnormal amygdala structure and function in lifelong premature ejaculation (PE) patients compared with healthy controls (HCs).

METHODS

Forty-four lifelong PE patients and thirty-one HCs were enrolled in this study. Each subject was diagnosed with PE using a Premature Ejaculation Diagnostic Tool (PEDT) and intravaginal ejaculation latency time (IELT) score. Based on t-tests and Pearson correlation analysis, the voxel-based morphometry and functional connectivity (FC) analyses were applied to evaluate brain structural and functional changes by using T1-weighted and resting-state functional magnetic resonance imaging scans.

RESULTS

Lifelong PE patients had decreased gray matter volume in the bilateral amygdala and increased FC between the amygdala and precuneus, posterior cingulate cortex (PCC), and middle temporal cortex (MTC), as well as decreased FC between the amygdala and precentral gyrus, insula, and inferior frontal gyrus. Moreover, significantly negative correlations between the IELT score and the mean z-score from amygdala-MTC (r = -0.49) and amygdala-PCC (r = -0.48) FC were found in lifelong PE patients.

CONCLUSIONS

Our study investigated the abnormal amygdala-related structure and connectivity patterns in PE patients, which might provide novel perspective for understanding the crucial role of the amygdala in the neural mechanism of PE.

KEY POINTS

• As one of the most common diseases in men, PE may be related to abnormal brain mechanisms. • Functional and structural magnetic resonance imaging used to explore amygdala abnormalities in PE patients. • The correlation between clinical scores and functional connectivity was used to assess the reasonability of the results.

Changes in the Amplitude of Low-Frequency Fluctuation in Patients With Lifelong Premature Ejaculation by Resting-State Functional MRI

INTRODUCTION

Dapoxetine is considered a first-line treatment for patients with lifelong premature ejaculation (PE), and current researches have showed with functional magnetic resonance imaging (fMRI) that patients with lifelong PE might have abnormal brain function, but differences in brain function before and after administration have not been reported.

AIM

The aim of this study was to determine some objective differences in brain function between patients with lifelong PE before and after administration and healthy individuals.

METHODS

In this study, 17 patients with lifelong PE and 11 healthy controls underwent clinical assessments and resting-state fMRI examination. After 4 weeks of treatment with dapoxetine 30 mg as needed, patients with PE underwent the same fMRI examination again 3 hours after dapoxetine administration.

MAIN OUTCOME MEASURE

The data were preprocessed using a data processing assistant for resting-state fMRI, and voxelwise amplitude of low-frequency fluctuation (ALFF) maps was calculated to identify abnormal neural activity in the brain.

RESULTS

(a) The ALFF of patients with PE was significantly lower in the bilateral hippocampus and thalamus and higher in the left fusiform and lingual gyrus than that of healthy controls; (b) decreased and increased ALFF in patients with PE recovered after dapoxetine administration.

CONCLUSION

We preliminarily identified the relevant sites by analyzing changes in the ALFF in patients with lifelong PE. Analyzing ALFF changes in the brain by resting-state fMRI is an effective method to study PE, and it might provide a reference for disease diagnosis and future research. Yubo M, Lianjia H, Cuiping M, et al. Changes in the Amplitude of Low-Frequency Fluctuation in Patients With Lifelong Premature Ejaculation by Resting-State Functional MRI. Sex Med 2021;9:100287.

Abnormal Thalamic Metabolism in Patients With Lifelong Premature Ejaculation

BACKGROUND

Although some recent neuroimaging studies have indicated the abnormal brain structure or function in patients with lifelong premature ejaculation (LPE), whether and how the abnormal thalamic function participates in processing sexual behavioral information are still unclear in patients with LPE.

AIM

The aim of this study was to assess the changes in the thalamus metabolism and structural integrity in patients with LPE.

METHODS

We performed a multimodal magnetic resonance approach in a 3.0 T system, including proton magnetic resonance spectroscopy (¹H-MRS), diffusion tensor imaging, and volumetric analysis to detect the differences in thalamic metabolism and structure between 20 patients with LPE and 15 healthy controls.

OUTCOMES

We analyzed and correlated the clinical symptoms of the subjects with significant ¹H-MRS-based features. Peak areas of N-acetylaspartate, choline, creatine (Cr), and glutamate/glutamine (Glu) were calculated with the LCModel software.

RESULTS

Diffusion tensor imaging and volumetric analysis of thalami showed no differences between the 2 groups. On the contrary, ¹H-MRS study disclosed that both Glu concentrations and Glu/Cr ratio values in the thalami of patients with LPE were remarkably increased when compared with healthy controls (P < .01 for both variables). In addition, both the intravaginal ejaculatory latency time score and Chinese Index of Sexual Function for Premature Ejaculation-5 score were negatively related to increased Glu concentrations and Glu/Cr ratio values.

CLINICAL IMPLICATIONS

Glutamatergic activity changes of thalamus may be an underlying indicator for evaluating sensory conduction efficiency in patients with LPE.

STRENGTHS & LIMITATIONS

The present study first found the abnormal thalamic metabolism in patients with LPE and contributed to a better understanding of the LPE etiology. Limitations include a cross-sectional study design with small samples and no examination of other brain areas.

CONCLUSION

Our findings show that the increase in glutamatergic activity of thalamus is related to LPE, suggesting that the increased Glu neurotransmission in the thalamus may contribute to the development of premature ejaculation. Xia J-D, Chen F, Zhang Q-J, et al. Abnormal Thalamic Metabolism in Patients With Lifelong Premature Ejaculation. J Sex Med 2021;18:275-283.

Aberrant default mode network and auditory network underlying the sympathetic skin response of the penis (PSSR) of patients with premature ejaculation: A resting-state fMRI study

INTRODUCTION

Hyperactivity of the sympathetic nervous system is considered as an important component involved in the pathological mechanisms of premature ejaculation (PE). However, the neural mechanisms of PE with high sympathetic activity are still not well understood.

METHODS

The activity of the sympathetic innervations in the penis was evaluated by the sympathetic skin response of the penis (PSSR) with an electromyograph and evoked potential equipment. Resting-state functional magnetic resonance imaging (fMRI) data were acquired from 18 PE patients with high sympathetic activity (sPE), 17 PE patients with normal sympathetic activity (nsPE), and 24 healthy controls (HC). We investigated the neural basis of sPE based on the measure of regional homogeneity (ReHo). Moreover, the correlations between brain regions with altered ReHo and PEDT scores and PSSR latencies in the patient group were explored.

RESULTS

Altered ReHo values among three groups were found in the temporal, cingulated, and parietal cortex in the default mode network (DMN), as well as the temporal cortex in the auditory network (AUD). Compared with HC, Patients with sPE had increased ReHo values of brain regions in DMN, AUD, and decreased ReHo values of brain regions in DMN. In addition, increased ReHo values were found in DMN of patients with nsPE, while decreased ReHo values were found in DMN and the attention network (AN). Moreover, sPE patients had increased ReHo values in AUD and decreased ReHo values in DMN when compared with nsPE patients. Finally, altered ReHo values of brain regions in DMN and AUD were associated with PEDT scores and PSSR latencies in the patient group.

CONCLUSION

Our results suggested that PE patients had abnormal ReHo values in DMN, AUD, and AN. Patients with sPE were characterized by increased neuronal activity in AUD and decreased activity in DMN. This highlighted the significances of DMN, AUD, and AN in the pathophysiology of PE and also provided potential neuroimaging biomarkers for distinguishing sPE from nsPE and HC.

Brain Functional Biomarkers Distinguishing Premature Ejaculation From Anejaculation by ALFF: A Resting-State fMRI Study

INTRODUCTION

Premature ejaculation (PE) and anejaculation (AJ) are 2 opposite disorders of male ejaculatory dysfunction. Recent studies have demonstrated that the process of ejaculation is mediated by certain neural circuits in the brain. However, different mechanisms between PE and AJ are still unclear.

AIM

Therefore, we used resting-state functional magnetic resonance imaging (fMRI) to explore the underlying neural mechanisms in patients with PE and AJ by measuring the amplitude of low-frequency fluctuations (ALFF).

METHODS

Resting-state fMRI data were acquired in 17 PE, 20 AJ patients and 23 matched healthy controls (HC).

MAIN OUTCOME MEASURE

Differences of ALFF values among the 3 groups were compared. We also explored the correlations between brain regions showing altered ALFF values and scores of Premature Ejaculation Diagnostic Tool (PEDT) in the PE group.

RESULTS

There were widespread differences of ALFF values among the 3 groups, which included left anterior cingulate gyrus, precentral and postcentral gyrus, paracentral lobule, superior temporal gyrus, calcarine fissure, putamen; right postcentral gyrus, paracentral lobule, middle temporal gyrus, putamen. Compared with HC, PE patients had greater ALFF in the right inferior frontal gyrus (opercular part), AJ patients had greater ALFF in the left postcentral gyrus. In addition, PE patients exhibited greater ALFF in the left Rolandic operculum, anterior cingulate gyrus, inferior frontal gyrus (orbital part), putamen, and right putamen when compared with AJ patients, as well as decreased ALFF in the right postcentral gyrus. Moreover, positive correlations were found between ALFF of left postcentral gyrus, inferior frontal gyrus (orbital part), right inferior frontal gyrus (opercular part), and PEDT scores.

CLINICAL IMPLICATIONS

The differences in central pathophysiological mechanisms between PE and AJ might be useful for improving the clinical diagnosis of ejaculation dysfunction.

STRENGTH & LIMITATIONS

Our results showed that the method of fMRI could identify the differences of ALFF between PE and AJ and that these alterations in ALFF were related to clinical function. However, this was a relatively small sample study, and further multimodal neuroimaging studies with large samples were needed.

CONCLUSION

The findings demonstrated that altered ALFF of frontal, parietal cortex, and putamen might help distinguish premature ejaculation from anejaculation. Abnormal function of these brain regions might play a critical role in the physiopathology of ejaculatory dysfunction of patients. Chen J, Yang J, Huang X, et al. Brain Functional Biomarkers Distinguishing Premature Ejaculation From Anejaculation by ALFF: A Resting-State fMRI Study. J Sex Med 2020;17:2331-2340.

Gene Variants in Premature Ejaculation: Systematic Review and Future Directions

INTRODUCTION

A growing number of genetic association studies have been performed to investigate the association between the genetic susceptibility alleles and the risk of premature ejaculation (PE); however, the results remain inconclusive.

OBJECTIVES

This systematic review aimed: (i) to determine whether an association exists between gene(s) or allelic variant(s) and PE; (ii) to assess whether the associations are consistent across studies in magnitude and direction, and (iii) to identify any limitation, gap, or shortcoming in the included studies.

METHODS

The literature search was conducted in PubMed, MEDLINE, Scopus, Cochrane Library, EMBASE, Academic Search Complete, Google Scholar, and CINAHL databases.

RESULTS

Different gene variants associated with PE were assessed. 25 genetic association studies met the inclusion criteria that investigated 11 genes, 2,624 men with PE compared with 9,346 men as controls, twins, and siblings. 19 studies demonstrated a significant association with PE, whereas 4 studies denied such a relationship. SLC6A4 gene polymorphism was investigated in 11 studies (7 studies demonstrated a significant relationship with PE, and 4 studies denied such a relationship). Dopamine transporter gene (DAT1) polymorphism was investigated in 4 studies exhibiting a significant relationship. Androgen receptor gene polymorphisms were investigated in 2 studies, 1 with a significant relationship and the other with a non-significant relationship. Oxytocin gene polymorphisms and tryptophan hydroxylase 2 gene polymorphisms were investigated in 2 studies with a significant relationship.

CONCLUSION

While this review has highlighted several genes that may be potentially associated with PE such as SLC6A4, limitations such as variance in study methods, lack of robust findings, small sample sizes, lack of reproducibility, quality of reporting, and quality of assessment remain a major concern. Further efforts such as standardizing reporting, exploring complementary designs, and the use of genome-wide association studies technology are warranted to test the reproducibility of these early findings. Mostafa T, Abdel-Hamid IA, Taymour M, et al. Gene Variants in Premature Ejaculation: Systematic Review and Future Directions. Sex Med Rev 2020;8:586-602.

Male Ejaculatory Endophenotypes: Revealing Internal Inconsistencies of the Concept in Heterosexual Copulating Rats

Distinct manifestations of sexual behavior are conceived as separate phenotypes. Each sexual phenotype is assumed to be associated with a characteristic brain. These notions have justified the phenotyping of heterosexual copulator males based upon their ejaculation's latencies (EL) or frequencies (i.e., cumulative ejaculation number; EN). For instance, men and male rats showing premature, normal or retarded ejaculation are assumed to be distinctive endophenotypes. This concept, nonetheless, contradicts past and recent evidence that supports that sexual behavior is highly variable within each sex, and that the brain sexual functional morphology represents an intricate sexual phenotypic mosaic. Hence, for ejaculatory male endophenotypes to be considered as a valid biological concept, it must show internal consistency at various levels of organization (including genetic architectures), after being challenged by intrinsic and/or extrinsic factors. We then judged the internal consistency of the presumed ejaculatory endophenotypes by assessing whether copulatory behavior and the expression of copulation relevant genes and brain limbic structures are specific to each of the presumed EL- or EN-ejaculatory endophenotypes. To do this, copulating male rats were first phenotyped in groups consistently displaying short, average or long ejaculation latencies or very high, high, average, low or very low EN, based in their copulatory performance. Then, the internal consistency of the presumed EL- or EN-endophenotypes was tested by introducing as covariates of phenotyping other copulatory parameters (e.g., number of intromissions) in addition to EL or EN, or by analyzing the expression levels of genes encoding for estrogen receptor alpha, progesterone receptor, androgen receptor, aromatase, DNA methyl-transferase 3a and DNA methyl-transferase 1 in the amygdala, medial preoptic area, ventromedial hypothalamus and olfactory bulb. We found that even though there were group-level differences in all the variables that were studied, these differences did not add-up to create the presumed EL- or EN-ejaculatory endophenotypes. In fact, the extensive overlapping of copulatory parameters and expression levels of copulation relevant genes in limbic structures across EL- or EN-phenotyped copulating male rats, is not consistent with the hypothesis that distinct ejaculatory endophenotypes exist and that they are associated with specific brain characteristics.

Striatum-related Intrinsic Connectivity Deficits in Lifelong Premature Ejaculation Patients

OBJECTIVE

To investigate abnormal intrinsic connectivity of striatum in lifelong premature ejaculation (PE) patients compared with healthy controls (HCs).

METHODS

Forty-seven lifelong PE patients and 30 healthy controls were enrolled in the present study and underwent resting-state functional magnetic resonance imaging. The functional connectivity (FC) analysis and 2-sample t tests were applied to investigate the alterations of striatum-related connectivity in patients compared with HCs (significant threshold at P < .05, false discovery rate corrected), and during which Fisher's r-to-z transformation was adopted and the resulting z values were used as the statistical FC values. Correlation analysis was performed to test possible relationships between the imaging findings and clinical characteristics in the patient group (P < .05, Bonferroni correction).

RESULTS

The results showed that compared with HCs, lifelong PE patients had significantly decreased FC between the right caudate and insula, superior temporal pole (STP) and orbitofrontal cortex (OFC) as well as decreased FC between the bilateral putamen and insula, STP and middle cingulate cortex (MCC). Meanwhile, patients had significantly increased FC between the left caudate and OFC, and increased FC between the right putamen and fusiform. The mean FC value from the caudate-OFC, caudate-insula, and caudate-STP connectivity negatively correlated with the Premature Ejaculation Diagnostic Tool score, separately.

CONCLUSION

The current study showed the functional abnormality of lifelong PE in multiple brain regions implicated in sensation, motivation, and ejaculation-related inhibitory control, which may improve our understanding of the abnormal striatum-related neural mechanisms in lifelong PE patients.

Altered Functional Connectivity of Hypothalamus in Lifelong Premature Ejaculation Patients

BACKGROUND

As one of the most prevalent sexual dysfunctions in men, lifelong premature ejaculation (PE) often leads to patient distress. The hypothalamus is implicated in the ejaculatory control of healthy males. However, we do not know whether the hypothalamus-related intrinsic connectivity is altered in lifelong PE patients.

PURPOSE

To investigate abnormal intrinsic connectivity of the hypothalamus in lifelong PE patients compared with healthy controls (HCs).

STUDY TYPE

Prospective pilot study using cross-sectional data of patients and HCs.

SUBJECTS

Forty-seven lifelong PE patients and 30 HCs were included in this study.

FIELD STRENGTH/SEQUENCE

3.0T MRI scanner for T₁ -weighted imaging using spoiled gradient recalled echo sequence and functional imaging using a single-shot gradient recalled echo sequence.

ASSESSMENT

Preprocessing of MRI data and hypothalamus-seeded functional connectivity (FC) computation were performed using DPABI4.1.

STATISTICAL TESTS

The two-sample t-test within SPM12 was adopted to examine possible alterations of intrinsic connectivity of hypothalamus in lifelong PE patients compared with HCs including anxiety and depression scores as covariates (false discovery rate-corrected, P < 0.05). The correlation analysis was then used to assess possible associations between the imaging findings and clinical features in the patient group (Bonferroni-corrected, P < 0.05).

RESULTS

Compared with HCs, lifelong PE patients had decreased hypothalamus-seeded FC in the left orbitofrontal cortex, bilateral insula, superior temporal cortex, superior temporal pole, middle temporal cortex, left fusiform, right parahippocampal gyrus, and right cerebellum. The intravaginal ejaculatory latency time positively correlated with the mean z-score from the hypothalamus-insula (r = 0.45) and hypothalamus-cerebellum (r = 0.48) intrinsic connectivity, separately.

DATA CONCLUSION

We have shown that hypothalamus-seeded FC alterations and the correlations between the aforementioned abnormal FC alterations and intravaginal ejaculatory latency time. The current findings may promote the understanding of the hypothalamus-related neural mechanisms involved in the abnormal ejaculatory information processing in lifelong PE patients.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY STAGE: 3 J. Magn. Reson. Imaging 2020;52:778-784.

Abnormal Resting-State Functional Connectivity in the Whole Brain in Lifelong Premature Ejaculation Patients Based on Machine Learning Approach

Recent neuroimaging studies have indicated that abnormalities in brain structure and function may play an important role in the etiology of lifelong premature ejaculation (LPE). LPE patients have exhibited aberrant cortical structure, altered brain network function and abnormal brain activation in response to erotic pictures. However, it remains unclear whether resting-state whole brain functional connectivity (FC) is altered in LPE patients. Machine learning analysis has the advantage of screening the best classification features from high-throughput data (such as FC), which has the potential to identify the pathophysiological targets of disease by establishing classification indicators for patients and healthy controls (HCs). Therefore, the supported vector machine based classification model using FC as features was used in the present study to confirm the most specific FCs that distinguish LPE patients from healthy controls. After feature selection, the remained features were used to build the classification model, with an accuracy 0.85 ± 0.14, sensitivity of 0.92 ± 0.18, specificity of 0.72 ± 0.30, and recall index of 0.85 ± 0.17 across 1000 testing groups (100 times 10-folds cross validation). After that, two-sample t-tests with family-wise error correction were used to compare these features that occur more than 500 times during training steps between LPE patients and HCs. Four FCs, (1) between left medial part of orbital frontal cortex (mOFC) and right mOFC, (2) between the left rectus and right postcentral gyrus, (3) between the right insula and left pallidum, and (4) between the right middle part of temporal pole and right inferior part of temporal gyrus showed significant group difference. These results demonstrate that resting-state brain FC might be a discriminating feature to distinguish LPE patients from HCs. These classification features, especially the FC between bilateral mOFC, provide underlying abnormal central functional targets in LPE etiology, which offers a novel alternative target for future intervention in LPE treatment.