Altered spinal cord activity during sexual stimulation in women with SCI: a pilot fMRI study

Detection of resting-state functional connectivity in the lumbar spinal cord with 3T MRI

Functional MRI (fMRI) of the spinal cord is an expanding area of research with potential to investigate neuronal activity in the central nervous system. We aimed to characterize the functional connectivity features of the human lumbar spinal cord using resting-state fMRI (rs-fMRI) at 3T, using region-based and data-driven analysis approaches. A 3D multi-shot gradient echo resting-state blood oxygenation level dependent-sensitive rs-fMRI protocol was implemented in 26 healthy participants. Average temporal signal-to-noise ratio in the gray matter was 16.35 ± 4.79 after denoising. Evidence of synchronous signal fluctuations in the ventral and dorsal horns with their contralateral counterparts was observed in representative participants using interactive, exploratory seed-based correlations. Group-wise average in-slice Pearson's correlations were 0.43 ± 0.17 between ventral horns, and 0.48 ± 0.16 between dorsal horns. Group spatial independent component analysis (ICA) was used to identify areas of coherent activity¸ and revealed components within the gray matter corresponding to anatomical regions. Lower-dimensionality ICA revealed bilateral components corresponding to ventral and dorsal networks. Additional separate ICAs were run on two subsets of the participant group, yielding two sets of components that showed visual consistency and moderate spatial overlap. This work shows feasibility of rs-fMRI to probe the functional features and organization of the lumbar spinal cord.

Effect of Physiological Noise on Thoracolumbar Spinal Cord Functional Magnetic Resonance Imaging in 3T Magnetic Field

Introduction:

Functional Magnetic Resonance Imaging (fMRI) methods have been used to study sensorimotor processing in the spinal cord. However, these techniques confront unwanted noises to the measured signal from the physiological fluctuations. In the spinal cord imaging, most of the challenges are consequences of cardiac and respiratory movement artifacts that are considered as significant sources of noise, especially in the thoracolumbar region. In this study, we investigated the effect of each source of physiological noise and their contribution to the outcome of the analysis of the blood-oxygen-level-dependent signal in the human thoracolumbar spinal cord.

Methods:

Fifteen young healthy male volunteers participated in the study, and pain stimuli were delivered on the L5 dermatome between the two malleoli. Respiratory and cardiac signals were recorded during the imaging session, and the generated respiration and cardiac regressors were included in the general linear model for quantification of the effect of each of them on the task-analysis results. The sum of active voxels of the clusters was calculated in the spinal cord in three correction states (respiration correction only, cardiac correction only, and respiration and cardiac noise corrections) and analyzed with analysis of variance statistical test and receiver operating characteristic curve.

Results:

The results illustrated that cardiac noise correction had an effective role in increasing the active voxels (Mean±SD = 23.46±9.46) compared to other noise correction methods. Cardiac effects were higher than other physiological noise sources

Conclusion:

In summary, our results indicate great respiration effects on the lumbar and thoracolumbar spinal cord fMRI, and its contribution to the heartbeat effect can be a significant variable in the individual fMRI data analysis. Displacement of the spinal cord and the effects of this noise in the thoracolumbar and lumbar spinal cord fMRI results are significant and cannot be ignored.

What Has Been Learned from Magnetic Resonance Imaging Examination of the Injured Human Spinal Cord: A Canadian Perspective

Magnetic resonance imaging (MRI) has transformed the way surgeons and researchers study and treat spinal cord injury. In this narrative review, we explore the historical context of imaging the human spinal cord and describe how MRI has evolved from providing the first visualization of the human spinal cord in the 1980s to a remarkable set of imaging tools today. The article focuses in particular on the role of Canadian researchers to this field. We begin by outlining the clinical context of traumatic injury to the human spinal cord and describe why current MRI standards fall short when it comes to treating this disabling condition. Parts 2 and 3 of this work explore an exciting and dramatic shift in the use of MRI technology to aid in our understanding and treatment of traumatic injury to the spinal cord. We explore the use of functional imaging (part 2) and structural imaging (part 3) and explore how these techniques have evolved, how they are used, and the challenges that we face for continued refinement and application to patients who live with the neurological and functional deficits caused by injury to the delicate spinal cord.

Ten Key Insights into the Use of Spinal Cord fMRI

A comprehensive review of the literature-to-date on functional magnetic resonance imaging (fMRI) of the spinal cord is presented. Spinal fMRI has been shown, over more than two decades of work, to be a reliable tool for detecting neural activity. We discuss 10 key points regarding the history, development, methods, and applications of spinal fMRI. Animal models have served a key purpose for the development of spinal fMRI protocols and for experimental spinal cord injury studies. Applications of spinal fMRI span from animal models across healthy and patient populations in humans using both task-based and resting-state paradigms. The literature also demonstrates clear trends in study design and acquisition methods, as the majority of studies follow a task-based, block design paradigm, and utilize variations of single-shot fast spin-echo imaging methods. We, therefore, discuss the similarities and differences of these to resting-state fMRI and gradient-echo EPI protocols. Although it is newly emerging, complex connectivity and network analysis is not only possible, but has also been shown to be reliable and reproducible in the spinal cord for both task-based and resting-state studies. Despite the technical challenges associated with spinal fMRI, this review identifies reliable solutions that have been developed to overcome these challenges.

Sexual concerns after Spinal Cord Injury: An update on management

BACKGROUND

Spinal Cord Injury (SCI) causes neurological impairment with resultant neurogenic sexual dysfunction which can compound preexisting psychological and medical sexual concerns. Understanding these concerns is important in managing the lifelong needs of persons with SCIs.

OBJECTIVES

To provide an overview of the impact of SCI on sexuality along with a framework for treatment of sexual concerns. To briefly review male infertility and its treatments and pregnancy in females after SCI.

METHODS

Interdisciplinary literature review and synthesis of information.

RESULTS

The average age at SCI is increased, thus persons with SCIs may have preexisting sexual concerns. Sexual activity and satisfaction are decreased after SCI. Psychogenic sexual arousal is related to remaining sensation in the T11-L2 dermatomes. Orgasm occurs in approximately 50% of persons with SCIs with all injuries except subjects with complete lower motor neuron (LMN) injuries affecting the lowest sacral segments A structured approach to treatment including assessing preinjury function, determining the impact of injury, education, assessing and treating iatrogenic sexual dysfunction and treatment of concomitant problems is recommended. Basic and advanced methods to improve sexual arousal and orgasm are discussed and treatment of anejaculation and issues associated with pregnancy and SCI are reviewed.

CONCLUSIONS

Sexual satisfaction is impaired after SCI; however, education and new therapies can improve responsiveness. Future research is warranted to improve sexual function and fertility potential in persons with SCIs.

Orgasm and SCI: what do we know?

STUDY DESIGN

narrative review OBJECTIVES: To determine the percentage of persons with SCI able to achieve orgasm and ejaculation, the associations between ejaculation and orgasm and the subjective and autonomic findings during these events, and the potential benefits with regards to spasticity.

SETTING

Two American medical centers METHODS: Data bases were searched for the terms orgasm and SCI and ejaculation and SCI. Search criteria were human studies published in English from 1990 to 12/2/2016.

RESULTS

Approximately 50% of sexually active men and women report orgasmic ability after SCI. There is a relative inability of persons with complete lower motor neuron injuries affecting the sacral segments to achieve orgasm. Time to orgasm is longer in persons with SCIs than able-bodied (AB) persons. With orgasm, elevated blood pressure (BP) occurs after SCI in a similar fashion to AB persons. With penile vibratory stimulation and electroejaculation, BP elevation is common and prophylaxis is recommended in persons with injuries at T6 and above. Dry orgasm occurs approximately 13% of times in males. Midodrine, vibratory stimulation, clitoral vacuum suction, and 4-aminopyridine may improve orgasmic potential.

CONCLUSIONS

Depending on level and severity of injury, persons with SCIs can achieve orgasm. Sympathetically mediated changes occur during sexual response with culmination at orgasm. Future research should address benefits of orgasm. Additionally, inherent biases associated with studying orgasm must be considered.