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Translumbosacral Neuromodulation Therapy for Fecal Incontinence: A Randomized Frequency Response Trial

Rao, Satish S.C. MD, PhD, FRCP (LON)1; Xiang, Xuelian MD1; Sharma, Amol MD1; Patcharatrakul, Tanisa MD1; Yan, Yun MD1; Parr, Rachael MS1; Ayyala, Deepak PhD2; Hamdy, Shaheen MD3

Author Information
The American Journal of Gastroenterology: January 2021 - Volume 116 - Issue 1 - p 162-170
doi: 10.14309/ajg.0000000000000766



Fecal incontinence (FI) affects 8%–15% of the ambulatory population in United States (1,2), predominantly women and the elderly, and 45% of nursing home residents (3,4). It adversely affects quality of life (QOL) and psychosocial function and poses a major healthcare burden (5). A significant problem has been a lack of effective therapies for FI, largely because of the absence of mechanistically based noninvasive therapies and a dearth of understanding on how treatments affect the core pathophysiological mechanisms of FI.

Although several risk factors for FI have been identified that include obstetric and surgical trauma, diabetes, diarrhea, and neurologic conditions, the pathophysiology of FI is also driven by structural (anal sphincters and puborectalis), sensory (rectal sensation), accommodation (rectal capacity), stool characteristics (diarrhea), and anorectal neuropathy (6–8). In fact, more than one of these factors were responsible for FI in over 80% of patients (6,7). In addition, women with sphincter defects were more likely to develop incontinence if they had neuropathy (9), and in asymptomatic nulliparous women, increased age was associated with neurogenic injury, which partly explains their weak squeeze pressures.

Until recently, however, the assessment of pelvic neuropathy has been challenging (7). The advent of translumbosacral anorectal magnetic stimulation (TAMS) test that uses minimally invasive magnetic stimulation of the lumbar and sacral nerve plexi to record the anal- and rectal motor-evoked potentials (MEPs) has enabled improved detection of neuropathy. In studies of patients with moderately severe FI and spinal cord injury, both anal and rectal MEP latencies were significantly prolonged when compared with healthy controls (8,9). Recently, in a study of the brain-gut axis, these findings were further reaffirmed (10), and peripheral lumboanorectal and sacroanorectal neuropathies were found to be the primary locus for neuronal derangement, and the neuropathy was often asymmetrical and patchy (10). These findings indicate that a progressive anorectal neuropathy could play a significant role in the pathogenesis of FI (6,11).

We hypothesized that repetitive translumbar magnetic stimulation and transsacral magnetic stimulation (rTSMS) at one or more frequencies will significantly improve FI symptoms through neuroplasticity, i.e., the ability of the nervous system to adapt and change in response to repetitive stimulation and by enhancing both the peripheral and central neural excitability. This approach stems from our preliminary studies which suggested that translumbosacral neuromodulation therapy (TNT) improves neuropathy and anorectal pain in patients with levator ani syndrome (12) and induces central neuroplastic changes that are frequency dependent in FI (13,14), and those of others showing that sacral nerve stimulation enhances somatosensory cortical changes and expression of neural markers in rats (15). If so, TNT could provide a multidimensional therapeutic benefit-enhanced anal muscle strength, improve neuropathy, improve stool awareness, and improve rectal capacity.

Our aims were to test the feasibility, clinical effects, safety, and optimal frequency (dose) of TNT in patients with FI who were randomized to receive one of 3 frequencies (1, 5, or 15 Hz) of repetitive translumbar and rTSMSs. We assessed the impact of treatment with each frequency on FI episodes, bowel symptoms, FI severity, and QOL, both within each group and between groups. We also determined the mechanistic effects of TNT on the underlying pathophysiology of FI by examining the changes in anorectal and neurophysiological functions.


Patients with FI were recruited from 2 academic centers, Augusta, United States, and Manchester, UK. The study was conducted between April 2015 and March 2018. All patients had a structured interview and received a physical examination—a colonoscopy to exclude structural pathology and biochemical evaluation as well as anorectal manometry, anal ultrasound, and TAMS test (see CONSORT Checklist, Supplementary Digital Content 1, Once eligible for screening, participants signed an informed consent approved by the human ethics board (No. 619411). They first maintained a 2-week prospective stool diary in which they recorded their daily stool habit, number of incontinence episodes, whether stools were formed or loose on a Bristol Stool Form Scale (BSFS), whether they used pads, severity of leakage amount (1 = mild, 2 = moderate, and 3 = excessive), whether they experienced stool urgency, and medications for stooling (16,17). The inclusion criteria were a history of recurrent episodes of FI for 6 months that was nonresponsive to diet, fiber, antidiarrheals and Kegels exercise, and absence of colonic mucosal disease (colonoscopy + biopsy), and on a 2-week stool diary, patients reported at least 1 episode of solid or liquid FI/wk. Patients were excluded if they had severe diarrhea (>6 liquid stools/d, Bristol scale >6); were on opioids; tricyclics (except on stable doses > 3 months); severe depression; severe comorbid illnesses such as cardiac disease, Chronic Obstructive Pulmonary Disease, or chronic renal failure; previous gastrointestinal surgery; neurologic diseases (e.g., head injury, epilepsy, multiple sclerosis, strokes, and spinal cord injury); impaired cognizance (minimental score of < 15/25) and/or legally blind; metal implants; pacemakers; radical hysterectomy; ulcerative and Crohn's colitis; and rectal prolapse or inflamed hemorrhoids. Patients were allowed to continue their baseline antidiarrheals, bile sequestrants, or fiber supplements throughout the study.

Study protocol

(See Flow Chart, Figure.1): Enrolled patients filled out a detailed questionnaire about their bowel symptoms and FI, as well as the Fecal Incontinence Severity Index (FISI) (18), Fecal Incontinence Symptom Severity (FISS) (19), Fecal incontinence quality of Life (FI-QOL) (20), and a Subject Global Assessment Scale (SGA), both at baseline and end of study.

Figure 1.
Figure 1.:
Consort flow diagram of study participants. CVA, cerebrovascular accident; ITT, intention to treat.

Next, patients underwent a high resolution anorectal manometry and TAMS tests to evaluate anorectal physiology, both at baseline and after treatment. A circumferential, 12-sensor, solid-state probe (ManoScan AR Catheter; Medtronics, MN) with a 4-cm long balloon was placed into the anorectum to perform high-resolution anorectal manometry. Details of the manometric methods have been described previously (16,20). Patients also underwent an anal ultrasound at baseline using a standard probe (BK Medical 2052; BK Medical Holding Company, UK), and the sphincter thickness, integrity, defects, and scarring were assessed.

TAMS test was performing by placing a probe into the rectum containing 2 pairs of bipolar steel ring electrodes (Gaeltec Devices Ltd., Dunvegan, Scotland). When the probe was correctly positioned, the proximal electrodes were located at 8 cm and the distal electrodes were located at 1.5 cm from the anal verge. This probe was used for recording both anal MEP and rectal MEP (8). The magnetic stimuli were delivered using the Magstim Rapid (2) stimulator (The Magstim Company Limited, Whiteland, Wales, UK) on each side at the L3 and the S3 levels, both about 4 cm lateral to the midline (8). At least 5 MEP recordings with an anal or rectal MEP response of at least 10 μV was considered adequate.

TNT therapy

Patients were randomized to one of 3 frequencies (1, 5 or 15 Hz) of TNT therapy. Six sessions of treatment were given at weekly intervals. The TAMS test was used to determine the motor threshold intensity, defined as the minimum level of magnetic stimulation intensity required to achieve an anal and rectal MEP response of 10 μV together with fine twitching of the posterior tibialis muscle. The intensity for repetitive translumbar (repetitive translumbar magnetic stimulation) and repetitive transsacral (rTSMS) magnetic stimulation was set at either 50% above this threshold or lower, if patient was unable to tolerate this intensity, as recommended by safety guidelines (21). Next, a 70-mm air film self-cooling coil (Magstim) was positioned randomly over one of the 4 sites (right or left lumbar/right or left sacral), held in place by a coil fixator (Air Film ® Coil support stand; The Magstim Company Ltd, Whitland, Wales, UK), and 300 stimulations of magnetic energy were delivered (Magstim Rapid). After a 3 min rest, the cycle was repeated (Total = 600 stimulations/site). The coil was moved to the next site, and after a rest period of 5–10 minutes, the stimulations were repeated using the threshold intensity for that site. All 4 sites were stimulated (total per session = 2,400 stimulations). Daily stool diaries were kept. Patients returned at weekly intervals for repeat treatment sessions. After their last treatment session, anorectal manometry, TAMS test, FI severity measures, and QOL were reassessed.

Measurements and outcomes.

The results obtained for the FI symptoms, physiologic and QOL measures, before and after treatment, and the differences between the 3 treatment frequencies were compared using an intention-to-treat (ITT) analysis. The clinical, manometric, and TAMS data were analyzed by an independent investigator not involved with performing TNT therapy.

The primary outcome measure was defined as the change in weekly episodes of FI. Based on this measurement, we assessed the responder rate as a coprimary outcome measure. A responder was defined as an individual who showed at least 50% reduction in FI episodes after treatment. The secondary outcome measures that were assessed from the stool diaries included stool frequency, stool consistency (Bristol Stool Form Scale, 1–7), and the use of pads. The FI severity analysis comprised several measures including the SGA scale that assessed the overall bowel satisfaction on a visual analog scale (0 [absent] to10 [severe]), the FISI that assessed improvement on a scale of 0 (no leakage) to 61 (most frequent) and the FISS scale that assessed FI on a scale of 4 (mild) to 13 (severe) (19,22). The FI- QOL assessed the changes in 4 QOL domains that included effects on lifestyle, coping, embarrassment, and depression (20).

The anorectal function was assessed by the changes in anal resting, squeeze and sustained sphincter pressures (22), the rectal sensory thresholds for first sensation, urge to defecate and maximum tolerable volume, and the rectal compliance (dv/dp) (23,24). The MEP latency was defined as the interval between the onset of stimulus and the onset of the individual rectal or anal MEP waveform and was expressed in milliseconds (8,10). An abnormal MEP latency (neuropathy) was defined as a value that was higher than the 95% confidence interval of healthy controls (10). A data safety monitoring board was established to oversee adverse events and adjudicate them. Data were collected on paper case report forms after performing the various assessments including prospective stool diary information, and then entered into a secure excel database, stored, and backed up. Next, the data were transferred to the biostatistician for statistical analysis. This study did not include a plan for data sharing.

Power and sample size calculations

We used the relative difference in the number of FI episodes as the measure to determine the sample size for this study. We assumed that the number of FI episodes within each of the 3 treatment arms has a coefficient of variation (ratio of SD to mean) of 0.25 (1:4). For each of the 3 treatment arms, to observe a 20% reduction in the number of FI episodes within the treatment arm with 80% power, at 5% significance level, a sample of 12 subjects were needed, i.e., a total of 36 subjects.

Randomization procedures

Subjects were randomly assigned to one of 3 treatment arms based on the frequency of magnetic stimulations: 1, 5, or 15 Hz. The randomization schedule was generated by the biostatistician using a permuted blocks of 3 method to ensure balance among the 3 treatment arms, and at each center, although making it highly improbable to predict the next treatment assignment. In addition, to assign the combination of testing conditions for each subject, we used a 2 × 2 factorial design—2 sides of lumbar (left/right) and 2 sides of sacral (left/right). Serially numbered, opaque, sealed envelopes containing the frequency dose assignments and the testing condition assignments were developed by the biostatistician and included a unique, site-specific randomization number, and this information was used by the research assistant who performed the tests and/or TNT study. The research assistants performing tests/treatment (X.X., T.P.) were not involved with data and statistical analysis. Safety and tolerability assessments were formed after each treatment and during their follow-up visits by a study coordinator who was blinded to the outcome results.

Statistical analyses

Quantitative variables are summarized using the sample average and SD for the baseline and post-treatment measures and the difference between the 2 time points, respectively. Because the sample sizes were too small to verify whether the outcome measures are normally distributed, we used nonparametric methods for the analysis. The changes in weekly FI episodes (primary outcome) and other secondary outcomes when compared with baseline in each of the 3 treatment groups were tested using a paired Wilcoxon signed-rank test. In addition, we tested the changes from baseline across the 3 treatment arms using the Kruskal-Wallis test. We compared the responder rate between the 3 treatment arms using a Fisher exact test. A nominal significance level of 5% was used throughout the analysis to determine the significance of variables. The data were analyzed using ITT analysis, and in case of missing data, the last observation was carried forward. All calculations were performed using R statistical analysis software (ver. 3.5.2).



Thirty-five patients were enrolled, of whom 2 were withdrawn, one because of severe diarrhea and one because of diarrhea and personal reasons before randomization (Figure 1). Thirty-three patients with FI (21 women, 58.9 ± 2.1 years) were randomized and completed at least 1 treatment session, and all were included in our ITT analysis. Three patients (9.1%) had diabetes mellitus, 2 patients (6.1%) had a history of back injury, 3 patients (9.1%) had a history of back surgery, 1 patient (3.1%) had ankylosing spondylitis, 1 patient (3.1%) had previous anal sphincteroplasty, 3 patients (9.1%) had hysterectomy, 2 (6.1%) patients had bladder surgery, 4 (12.1%) patients had hemorrhoid surgery, and 1 patient (3.1%) had prostate cancer with radiation treatment. The median number of pregnancies in the FI patients was 2 (range 0–5). One female patient (4.8%, 1/23) was nulliparous. Sixteen patients (76.3%) had vaginal deliveries, 3 of whom also had C-section, whereas 4 (19%) only had C-section. Eleven patients had vaginal delivery with tears and 6 had forceps-assisted delivery. Based on the predominant type of FI, 27.3% patients had passive FI, 39.4% patients had urge type FI, and 33.3% had both passive and urge type of FI (Table 1) (8,10). Except sex distribution, we found no differences in the demographic variables including bowel symptoms, severity or type of FI, and proportion of patients with anal sphincter defects or neuropathy between the 3 groups (Table 1). All patients included in the study were recruited from the Augusta site. Three patients were recruited from Manchester site (but not randomized), one had AE, one lost during screening (left city), and one declined to participate.

Table 1.
Table 1.:
Baseline demographic data, FI symptoms and severity, and anorectal neurophysiology characteristics

Effect of sex on baseline measurements

Despite random assignment, we found that more men were randomized to the 1 Hz arm compared with the other 2 groups (Table 1). Therefore, we assessed whether sex had a confounding effect on the treatment effects by assessing 7 different measures of FI. We found no significant differences between men and women on the duration of symptoms (P = 0.5106), number of leakage events (P = 0.5593), stool frequency (P = 0.2221), stool consistency (P = 0.3398), weekly use of pads (P = 0.0557), severity of FI (P = 0.7605), and urgency (P = 0.0688). Hence, it is unlikely that any imbalances in sex distribution within the 3 treatment arms during randomization had significant effect on results.

Effects of TNT on primary outcome measure

When compared with baseline, the number of stool leakage episodes per week significantly decreased (1 Hz, P = 0.01; 5 Hz, P = 0.022; and 15 Hz, P = 0.007) after TNT treatment in all 3 groups. The 1 Hz group showed the greatest reduction in mean (95% confidence interval) FI episodes (4.2 ± 2.8), followed by the 15 Hz group (3.4 ± 2.5) and the 5 Hz group (2 ± 1.7). There was no difference between the 3 groups (P = 0.2397) (Table 2). In addition, the coprimary outcome measure, the percentage of responders (95% confidence interval) was significantly higher (P = 0.04) in the 1 Hz group (90.9 ± 9.1%, 10/11) when compared with the 5 Hz group (36.4 ± 18.2%, 4/11) and the 15 Hz group (54.4 ± 18.2%, 6/11) (Figure 2). There was no difference between the 5 and 15 Hz groups (P = 0.66).

Table 2.
Table 2.:
Effects of 3 different TNT frequencies on bowel and FI symptoms and pad use
Figure 2.
Figure 2.:
The percentage of responders (n) in each of the 3 groups of FI patients. FI, fecal incontinence.

Effects of TNT on secondary outcome measures

The severity of the amount of stool leakage decreased only in the 1 Hz group (P = 0.012) compared with baseline (Table 2). Otherwise, there were no differences in the weekly mean stool frequency, mean stool consistency, frequency of pad usage, and urgency for defecation in all groups (Table 2).

Effects of TNT on FI severity

The SGA score decreased in the 1 Hz group (P = 0.02) and 15 Hz group (P = 0.01), respectively, but not in 5 Hz group (P = 0.1024) (Table 3), and there were no differences between the 3 groups (P = 0.501). There was no change in the FISI scores in either the 1 Hz group (P = 0.102) or 5 Hz group (P = 0.108) or 15 Hz group (P = 0.318). The FISS score decreased in all 3 groups but was only statistically significant in the 1 Hz group (P = 0.047), but not in 5 Hz group (P = 0.07) and in 15 Hz group (P = 0.1687). These measures indicate that the overall bowel function including severity of FI improved significantly, especially with the 1 Hz frequency when compared with baseline, but there were no differences between the 3 groups.

Table 3.
Table 3.:
Effects of TNT on FI severity and QOL domains

Effects of TNT on FI-QOL

After TNT therapy, several FI-QOL domains significantly improved in all 3 groups. Patients in the 1 and 5 Hz groups showed the greatest changes with regards to an improvement in at least 3 QOL domains (coping, depression, life-style, and embarrassment), whereas in the 15 Hz group, there was improvement in only 1 domain (Table 3).

Effects of TNT on anorectal manometry, rectal sensation, and compliance

The anal squeeze pressure and the sustained squeeze pressure increased in the 1 Hz group when compared with either baseline (P < 0.01) or the other 2 groups (P = 0.04), but there were no changes in the 5 and 15 Hz groups (Table 4). In addition, the rectal sensory thresholds for constant sensation, urge to defecate, and the maximal tolerable volume increased (P < 0.05) in the 1 Hz group, but there were no significant changes in the 5 or 15 Hz groups and between the 3 groups (Table 4). The rectal compliance (dv/dp) improved (P < 0.05) only in the 1 Hz group when compared with baseline, but not between groups, or in the 5 Hz and 15 Hz groups (Table 4).

Table 4.
Table 4.:
Effects of 3 different TNT frequencies on anal sphincter function, rectal sensation, and rectal compliance as assessed by changes in intrarectal pressure during incremental rectal distension

Effects of TNT on anorectal neuropathy

The latencies for the lumboanal and sacroanal MEPs were prolonged when compared with historical healthy controls (8,10) in all 3 groups at baseline (1 Hz, P < 0.0001; 5 Hz, P < 0.001; and 15 Hz, P < 0.001), indicating anal neuropathy. The baseline MEP latencies were not significantly different between groups. After TNT, the bilateral lumboanal and sacroanal MEP latencies were shortened in the 1 Hz group (P < 0.025), but only the right side sacroanal MEP in the 5 Hz group and bilateral lumboanal latencies in the 15 Hz group (Table 5). After TNT, only right side lumborectal MEP latency decreased (P = 0.025) in the 1 Hz and right side sacrorectal in the 5 Hz group (P = 0.044), but no changes in the 15 Hz group and at other rectal sites (Table 5). There were no differences between the 3 groups.

Table 5.
Table 5.:
Effects of 3 different TNT frequencies on anal and rectal neuropathy as assessed by bilateral lumbar and sacral MEPs

Adverse events, safety, and tolerability

There were 9 adverse events including 3 serious adverse events (Table 6). One adverse event was adjudicated as study related. A patient with chronic back pain reported worsening back pain, tingling, and numbness in legs for 1 day that subsided and patient completed all 6 sessions. The serious adverse events requiring hospitalization were fracture pelvis (1), gastrointestinal bleed secondary to the use of nonsteroidal anti-inflammatory drug (1), and pneumonia (1). Other adverse events were hand skin discoloration (1), kidney stone (1), transient hand tingling and numbness (1), fifth metatarsal fracture (1), and joint pains (1). None of the above were considered device related.

Table 6.
Table 6.:
Number of subjects with adverse events


Current treatments for FI remain unsatisfactory, with approximately one half of patients achieving acceptable continence (16,25–33). Moreover, previous studies have not systematically examined anorectal sensorimotor function, rectal capacity, anorectal neuropathy, and symptom severity in FI, especially after therapeutic interventions. Many studies have reported improvement based on subjective endpoints such as adequate relief of symptoms (34,35) without objective appraisal of outcomes. Of relevance, we have previously shown that temporary Sacral Nerve Stimulation decreases corticoanal excitability alongside improvements in FI symptoms but without changes in anorectal manometry (14). Here, we aimed to not only examine the effects of a novel, noninvasive therapy on FI symptoms but also to objectively evaluate the scientific basis for this therapy by evaluating manometric findings and neurophysiological changes.

We found that TNT at all 3 frequencies significantly decreased the number of FI episodes per week when compared with baseline (primary outcome), although there was no difference between the 3 groups. There were greater numbers of responders in the 1 Hz group when compared with the 5 and 15 Hz groups. Although there was some improvement in patients who received the 5 and 15 Hz frequencies, their effects were less pronounced than 1 Hz. These findings indicate that TNT is a useful treatment modality and that the 1 Hz frequency is a viable option for improving FI symptoms and restoring continence.

These 1 Hz centered changes were further substantiated by improvements in the severity of FI as assessed by several scales. The SGA that assesses a global improvement in the severity of FI on a visual analog scale, and the FISS that is an index based on the aggregate of multiple FI symptoms improved. In addition, the FI-QOL a validated FI specific instrument showed clinically meaningful (20) improvements in several key domains such as the coping/behavior skills, feelings of embarrassment, feelings of depression and self-perception, and improvements in life style. Thus, both the FI severity and its effects on QOL, which are major issues in these patients, improved substantially with TNT therapy.

The subjective improvements in symptoms were also matched by improvements in neuropathy and anorectal physiology. We found that the bilateral lumbar and sacral anal neuropathy in patients with FI significantly improved as evidenced by the shortening of anal MEP latencies with the 1 Hz frequency. There were lesser degrees of improvement in the anal neuropathy with either the 5 or 15 Hz frequency. This observation supports the notion that TNT improves bowel function possibly by improving the underlying neuropathy. It is likely that TNT induces neuroplasticity—the inherent ability of the neurons to adapt and change—and thereby alters the excitability in the motor neurons of the spinal cord, improving nerve conduction. However, this requires validation through direct recordings of the spinal cord.

We also observed significant improvements in anorectal sensorimotor physiology. The squeeze and sustained squeeze pressures improved especially with 1 Hz frequency, indicating that improved neuronal function also led to improved anal sphincter muscle function. Likewise, the rectal sensory thresholds and the rectal capacity also improved. It is likely that improvements in rectal sensation were in part because of improvement in rectal compliance. These findings suggest that TNT produces a multidimensional effect that leads to improvement in both symptoms and the underlying pathophysiology of FI.

The limitations of our study include the small number of subjects enrolled in each arm of the study, but it is important to recognize that this was both feasibility and optimal magnetic frequency assessment study, and not a full phase III randomized controlled trial. In addition, this was not a sham-controlled study, but the sample was adequate to provide promising data supporting this treatment approach. Although our subjects were randomized, there were more men in the 1 Hz arm of our study, and sex did not significantly influence the outcome of our study. However unlikely, TNT may be more efficacious in men, and a future sex-matched study is needed to address this aspect. Here, we tested 3 frequencies, and it is possible that other frequencies may also have physiological effects. Previous studies have suggested that higher frequency magnetic stimulation is more effective for delayed conduction and neuropathies especially in the central nervous system (36). In addition, 1 lumbosacral study showed that the 15 Hz frequency increased cortical excitability compared with 5 Hz, but 1 Hz was not tested, so this might explain a difference (13). By contrast, in another study, the 1 Hz lumbosacral stimulation did alter spinal responses (37). So, it might be that low frequencies are more effective in the peripheral neural circuitry—such as spinal cord and peripheral nerves. However, whether other lower frequencies such as 2 or 3 Hz are also effective is unclear. Likewise, we tested our subjects with a fixed dose of 2,400 magnetic stimulations, and whether a higher dose such as 3,600 or a lower dose such as 1,800 is equally or more effective is unknown. A sham-controlled, longer duration study with a larger sample size is needed to establish the efficacy of TNT because FI is a chronic problem.

In conclusion, our study showed that TNT improves bowel function and FI episodes in the short term, especially with the 1 Hz frequency, alongside improvements in anorectal neuropathy and anorectal sensorimotor function. These findings suggest that TNT is a safe and promising novel treatment for FI (see FIRaoNIH, Supplementary Digital Content 2,


Guarantor of the article: Satish S.C. Rao, MD, PhD, FRCP (LON).

Specific author contributions: S.S.C.R. – Project Director and Principal investigator-Augusta site, study concept and design, grant support, data analysis and interpretation, Translumbosacral neuromodulation therapy supervision, manuscript preparation, overall supervision, and critical revision. X.X.–Administering TNT therapy, conducting neurophysiology tests, conducting anorectal physiology test, Data analysis, tables, and figures. A.S. – Study conduct and recruitment and manuscript preparation. T.P.–Administering TNT therapy, conducting neurophysiology tests, and conducting anorectal physiology test. Y.Y.–Administering TNT therapy, conducting neurophysiology tests, data analysis, tables, and figures. R.P. – Study coordinator, patient recruitment, regulatory, and data collection. D.A.- Statistical design, statistical methods, and data analysis. S.H.–Principal investigator-Manchester site, study design, grant writing, manuscript preparation, and critical revision. All authors have approved the final version of the manuscript submitted.

Financial support: This study was supported by NIH—5R21 DK104127-02.

Potential competing interests: None to report.

Clinical Registered at Clinical no NCT02556151.

Study Highlights


  • ✓ FI affects 10% of the population, and there are inadequate randomized controlled trials that show efficacy or mechanistic understanding of noninvasive treatments.
  • ✓ Although anorectal neuropathy is a significant pathophysiological mechanism for FI, there has been no treatment for this dysfunction.
  • ✓ Neuromodulation therapy using repetitive magnetic stimulation has been shown to induce neuroplasticity and improve neuropathy in neurological disorders.


  • ✓ We examined the usefulness of a new treatment approach, TNT, and found that it improves FI symptoms and the underlying mechanism(s) of FI including neuropathy and QOL.
  • ✓ The effects were most pronounced with the 1 Hz frequency when compared with others.
  • ✓ TNT was efficacious in improving FI symptoms and the underlying pathophysiology.


We sincerely acknowledge the expert research assistance of Mrs. Amanda Schmeltz, Mrs. Meagan Gibbs O'banion, Ms. Ijeoma Azih, Ms. Shashana Fiedler, and statistical analysis support of Mrs. Patricia Hall. We also appreciate the technical assistance provided by Dr. K. Rattanakovit and Dr. M.L. Harris for the conduct of the study. Importantly, we thank Mrs. Helen Smith for her superb secretarial assistance.


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