Validation of actigraphy in hospitalised newborn infants using video polysomnography.

Actigraphy has been established as a reliable sleep assessment tool in adults; however, its utility in newborns remains unknown. Validation of actigraphy in newborns may provide a significant insight into the physiological and pathological acquisition process of mature diurnal sleep patterns and subsequent morbidities in both newborns and their mothers. Thus, the present study aimed to evaluate the accuracy of sleep-wake detection by overnight actigraphy in a cohort of newborns. Simultaneous recording of polysomnography and actigraphy data was performed in 40 newborns admitted to a tertiary neonatal intensive care unit (NICU). A mixed-effects logistic regression model to explain the sleep state identified by polysomnography was employed using the actigraphic activity score as a fixed independent variable and the individual newborn's identity as a random effect. To evaluate the usefulness of the actigraphic activity score as a surrogate marker of sleep, a receiver operating characteristic (ROC) curve analysis was performed using the variables that were used in the mixed-effects logistic regression model, and the area under the curve (AUC) was assessed. The results showed that polysomnography-determined sleep epochs were associated with a smaller activity index on actigraphy (odds ratio per 10 activity indices increase 0.81, 95% confidence interval [CI] 0.79-0.84). The AUC for the ROC curve was 0.87 (95% CI 0.87-0.88, range 0.54-0.99). An activity score of 124 showed the maximum overall accuracy (90.2%, 95% CI 87.7-92.1). Our present study suggests that sleep-wake states of NICU-hospitalised newborns can be precisely determined using actigraphy on the ankle.

Sleep problems, sleep duration, and use of digital devices among primary school students in Japan.

BACKGROUND: There is growing concern that screen time and media use in school-age children can negatively affect children's sleep. These negative effects are explained by three main underlying mechanisms: reduced sleep, time allocated for more media consumption; increased mental, emotional, or psychological stimulation by media content; and the effects of light emitted by digital devices on circadian rhythms and sleep physiology and arousal. In this study, we focused not only on sleep duration, but also on sleep problems. We conducted a large-scale survey to examine the relationship between excessive use of digital devices, Internet addictive behaviour, sleep duration, and sleep problems. METHODS: We conducted a cross-sectional study of children enrolled in 20 public primary schools in Nagoya City, Japan. Children's parents/guardians completed a questionnaire including the brief sleep questionnaire for Japanese children which is a shortened version of the 'Children's Sleep Habits Questionnaire'. Logistic regression analyses were used to identify associations between sleep problems and grade, sex, weekday sleep time, weekend sleep time, ownership of digital devices, frequent checking of digital devices, use of digital devices for more than 4 hours per day, and Internet addiction. RESULTS: In total, 8172 responses were received (91.6% response rate). After excluding incomplete responses, we analysed complete datasets for 6893 children with a mean age of 9.0 years. When adjusted for sex, grade, sleep duration on weekdays, and sleep duration on weekends, failure to control (odds ratio [OR] = 1.48; 95% confidence interval [CI]: 1.29-1.70; p < .001), more use than intended (OR = 1.27; 95% CI: 1.12-1.44; p < .001), and use to escape a dysphoric mood (OR = 1.30; 95% CI: 1.03-1.64; p = .027) were associated with children's sleep problems. A shorter weekday and a longer weekend sleep duration indicated a higher likelihood of sleep problems. CONCLUSIONS: After adjusting for sleep duration, a relationship was found between the three Internet addictive behaviours and sleep problems, but not ownership of digital devices. Parents and teachers may need to address screen media-related sleep problems in children, as these problems may be influenced by psychological factors.

Acceptance and commitment therapy combined with vestibular rehabilitation for persistent postural-perceptual dizziness: A pilot study.

PURPOSE: This study investigated the feasibility of acceptance and commitment therapy for persistent postural-perceptual dizziness and preliminarily verified the long-term effectiveness of the therapy. MATERIALS AND METHODS: This study implemented the within-group pre-post comparison design. We enrolled 27 adult patients who met the criteria of persistent postural-perceptual dizziness. They underwent a treatment program including acceptance and commitment therapy combined with vestibular rehabilitation once a week for a total of six sessions. The primary outcome was changes in the Dizziness Handicap Inventory score 6 months posttreatment. RESULTS: All 27 patients completed the acceptance and commitment therapy + vestibular rehabilitation program, and 25 patients (92.6%) could be followed for 6 months posttreatment. For 27 participants, the scores from pretreatment to 6 months posttreatment significantly declined (P < .001), and the Dizziness Handicap Inventory effect size was 1.11 (95% confidence interval = 0.80-1.42). At 6 months posttreatment, 11 patients (40.7%) achieved remission (the score ≤ 14), 16 (59.3%) achieved treatment response (reduction in the score ≥ 18), and 20 (74.1%) achieved remission and/or treatment response. CONCLUSIONS: Acceptance and commitment therapy is feasible for persistent postural-perceptual dizziness and might have long-term effectiveness. However, a randomized controlled trial is warranted.

Proton Pump Inhibitor Ameliorates Taste Disturbance among Patients with Laryngopharyngeal Reflux: A Randomized Controlled Study.

Patients with laryngopharyngeal reflux (LPR) were reported to suffer from hypogeusia that affects quality of life. Proton pump inhibitor (PPI) is a useful drug in the treatment of LPR, but its effect on hypogeusia is not known. We therefore assessed the effects of PPI or a histamine H2 receptor antagonist (H2 blocker) on hypogeusia among patients with LPR. Both PPI and H2 blocker could inhibit acid reflux. LPR was diagnosed with reflux finding score and reflux symptom index. The visual analogue scale (VAS) of taste disturbance symptoms and the gustatory tests were assessed before and 8 weeks after treatment with esomeprazole, a PPI (20 patients, aged 50.0 ± 1.7 years) or famotidine, a H2 blocker (20 patients, aged 47.1 ± 1.8 years). There were no significant differences in VAS scores and recognition thresholds for four basic tastes between the two groups before treatment. Only PPI therapy significantly decreased the VAS scores, suggesting the improvement of taste perception. Moreover, PPI therapy significantly decreased recognition thresholds for bitter taste in the anterior tongue (chorda tympani nerve area) and the thresholds in the posterior tongue (glossopharyngeal nerve area) for salty, sour, and bitter tastes. By contrast, H2-blocker therapy caused no significant changes of thresholds in the anterior tongue, but improved the threshold only for bitter in the posterior tongue, the value of which was however significantly higher than that in PPI group. In conclusion, PPI could ameliorate hypogeusia by improving bitter, salty, and sour tastes among patients with LPR.

Sleep Disturbance and Hyperactivity Detected by Actigraphy in Rats with Allergic Rhinitis or Attention-Deficit Hyperactivity Disorder.

Actigraphy is an easy and noninvasive method used to monitor human ultradian cycles. However, to our knowledge, it has been not applied to experiments with rodents. Therefore, using actigraphy, we assessed the ultradian cycles and behavior of rats. Rats with or without allergic rhinitis wore an actigraphy device, and triaxial acceleration was recorded. The counts that represent physical activity were lower from 8:00 to 20:00 than those from 20:00 to 8:00 in control rats, suggesting that their sleep phase was from 8:00 to 20:00 and their awake phase from 20:00 to 8:00. The counts from 8:00 to 10:00 were significantly higher in allergic rhinitis rats than in control rats (p < 0.01), suggesting the presence of difficulty with sleep induction in rats with allergic rhinitis. The counts from 18:00 to 20:00 were also significantly higher in allergic rhinitis rats than in control rats (p < 0.05), suggesting the presence of early awakening in rats with allergic rhinitis. Moreover, the counts were significantly higher in allergic rhinitis rats than in control rats from 20:00 to 8:00. These results suggest that rats with allergic rhinitis experienced hyperactivity disorder during the daytime. Additionally, hyperreactivity and difficulty with sleep induction were observed in 6-hydroxydopamine-lesioned rats, an animal model of attention-deficit hyperactivity disorder. This study shows for the first time that actigraphy can be successfully used for behavioral analysis in rodents. These rat models could be useful for analyzing the mechanisms involved in sleep disturbances and hyperactivity disorder.

Analysis of vestibular-balance symptoms according to symptom duration: dimensionality of the Vertigo Symptom Scale-short form.

BACKGROUND: Dizziness or vertigo is associated with both vestibular-balance and psychological factors. A common assessment tool is the Vertigo Symptom Scale (VSS) -short form, which has two subscales: vestibular-balance and autonomic-anxiety. Despite frequent use, the factor structure of the VSS-short form has yet to be confirmed. Here, we clarified the factor structure of the VSS-short form, and assessed the validity and reliability of the Japanese version of this tool. METHODS: We conducted a cross-sectional, multicenter, psychometric evaluation of patients with non-central dizziness or vertigo persisting for longer than 1 month. Participants completed the VSS-short form, the Dizziness Handicap Inventory, and the Hospital Anxiety and Depression Scale. They also completed the VSS-short form a second time 1-3 days later. The questionnaire was translated into Japanese and cross-culturally adapted. We conducted a confirmatory factor analysis followed by an exploratory factor analysis. Convergent and discriminant validity, internal consistency, and test-retest reliability were evaluated. RESULTS: The total sample and retest sample consisted of 159 and 79 participants, respectively. Model-fitting for a two-subscale structure in a confirmatory factor analysis was poor. An exploratory factor analysis produced a three-factor structure: long-duration vestibular-balance symptoms, short-duration vestibular-balance symptoms, and autonomic-anxiety symptoms. Regarding convergent and discriminant validity, all hypotheses were clearly supported. We obtained high Cronbach's α coefficients for the total score and subscales, ranging from 0.758 to 0.866. Total score and subscale interclass correlation coefficients for test-retest reliability were acceptable, ranging from 0.867 to 0.897. CONCLUSIONS: The VSS-short form has a three-factor structure that was cross-culturally well-matched with previous data from the VSS-long version. Thus, it was suggested that vestibular-balance symptoms can be analyzed separately according to symptom duration, which may reflect pathophysiological factors. The VSS-short form can be used to evaluate vestibular-balance symptoms and autonomic-anxiety symptoms, as well as the duration of vestibular-balance symptoms. Further research using the VSS-short form should be required in other languages and populations.

[Discrimination of Chin Electromyography in REM Sleep Behavior Disorder Using Deep Learning].

OBJECTIVE: The confirmation of abnormal behavior during video monitoring in polysomnography (PSG) and the frequency of rapid eye movement (REM) sleep without atonia (RWA) during REM sleep based on physiological indicators are essential diagnostic criteria for the diagnosis of REM sleep behavior disorder (RBD). However, no clear criteria have been established for the determination of the tonic and phasic activities of RWA. In this study, we investigated an RWA decision program that simulates visual inspection by clinical laboratory technicians. METHODS: We used the measurement data of 25 men and women (average age±standard deviation: 72.7±1.7 years) who visited the Sleep Treatment Center for PSG inspection due to suspected RBD. The chin electromyography (EMG) during REM sleep was divided into 30 s intervals, and RWA decisions were made on the basis of visual inspection by a clinical laboratory technician. We compared and investigated two machine-learning methods namely support vector machine (SVM) and convolutional neural network (CNN) for RWA decisions. RESULTS: When comparing SVM and CNN, the highest discrimination accuracy for RWA decisions was obtained when using the average rectified value (ARV) processed chin EMG images using CNN as a feature. We also estimated the prevalence of RBD on the basis of the Mahalanobis distance measure using the frequency of occurrence of both tonic and phasic activities calculated from a total of 25 subjects in the patient and healthy groups. Consequently, estimation of RBD prevalence using CNN resulted in misclassification of none of the subjects in the patient group and two subjects in the healthy group. CONCLUSIONS: In this study, we investigated the automatic analysis of PSG results focusing on RBD, which is a parasomnia. As a result, there were no misclassifications of patients in the 25 subjects in the patient or healthy groups based on the estimates of RBD prevalence using CNN. The prevalence estimation based on our proposed automated algorithm is considered effective for the primary screening for RBD.

Comparison of surgical outcomes of sleep surgeries preoperatively evaluated with drug-induced sleep endoscopy and Müller's maneuver.

Objective The purpose of this study was to compare surgical outcomes for obstructive sleep apnea (OSA) when the procedure was based on the results of drug-induced sleep endoscopy (DISE) vs. the awake Müller's maneuver (MM). Methods Forty-seven patients with OSA who underwent sleep surgery were included. Patients were divided into 2 groups according to their preoperative upper airway evaluation method. Twenty-five patients received only MM for surgical decision making (MM group), and 22 patients received both MM and DISE (DISE group) for surgical decision making. Results The surgical success rate of the DISE group was higher than that of the MM group (59% vs. 36%), but the difference was not significant (p = 0.118). The differences between pre- and postoperative apnea-hypopnea index (AHI) values in both the MM and DISE group were highly significantly different (p < 0.001). Fifteen patients in the DISE group (68.2%) received multi-level surgery, while in the MM group only 7 patients (28%) received multi-level surgery. Patients with more severe OSA (AHI > 22 or lowest O2 saturation < 81%) had better surgical outcomes when their surgical procedures were based on the findings of DISE, rather than those of MM. Conclusion The results indicate that DISE provides no benefits with respect to surgical outcomes for patients with mild to moderate OSA; however, for patients with more severe OSA surgical procedures based on DISE result in better outcomes.

Presence of exacerbating factors of persistent perceptual-postural dizziness in patients with vestibular symptoms at initial presentation.

Objective: To investigate the presence of exacerbating factors of persistent perceptual-postural dizziness (PPPD) in patients with vestibular symptoms during the early period after vestibular symptoms onset, and to examine possible predictive factors for developing PPPD later. Methods: One hundred and fifty-five consecutive patients with vestibular symptoms who presented less than 90 days from the onset were included in this study. They filled out the Niigata PPPD Questionnaire (NPQ) that consists of 12 questions on the exacerbating factors of PPPD. The NPQ scores of patients who developed PPPD were compared with those of patients who did not develop PPPD during the follow-up. Results: Seventy-eight of the155 patients (50.3%) showed positive NPQ scores (≥27 points). High NPQ scores were found in patients diagnosed with psychogenic dizziness and vestibular neuritis. During the follow up for an average of 543.3 days after the initial presentation, eight patients (10.3%) developed PPPD. Seven of these eight patients (87.6%) showed positive NPQ scores and all of them had all three exacerbating factors of PPPD at their initial presentation. The NPQ scores of the patients who developed PPPD (40.6 ± 11.6) were significantly higher than those of the patients who did not develop PPPD (26.4 ± 18.3; p <.05). Conclusion: Approximately a half of the patients with vestibular symptoms had exacerbating factors of PPPD in the early stages of the disease. Patients who develop PPPD are likely to have its exacerbating factors in the initial stages after presentation. Level of Evidence: 3.

Neuro-otological findings in psychiatric patients with nystagmus.

To evaluate whether neuro-otological tests have clinical significance in psychiatric patients with nystagmus who have inner ear and/or brain dysfunction, we performed neuro-otological tests on 56 psychiatric patients with nystagmus (38 men, 18 women) (age range 40-97; mean age ± SD 61.6 ± 10.5 years). Patients were classified according to the underlying diseases: schizophrenia (25 cases), organic psychiatric disorders (14 cases), alcoholism (16 cases) and excited mental retardation (1 case). Caloric test results showed a normal response in 30 (75%) cases, right canal paresis (CP) in 4 (10%), left CP in 4 (10%) and bilateral CP in 2 (5%). Therefore, 10 (25%) cases had CP. The results of the eye tracking tests (ETT) were sorted into five categories: 4 (8.2%) cases smooth (normal), 8 (16.3%) slightly saccadic, 28 (57.1%) saccadic, 8 (16.3%) ataxic, and 1 (2%) no tracking ability. Therefore, 45 (91.8%) cases had abnormal ETT results. Pure tone audiometry showed normal hearing in 24 (47.1%) cases, right hearing loss (HL) in 3 (5.8%), left HL in 3 (5.8%) and bilateral HL in 21 (41.2%). Therefore, 27 (52.9%) cases had HL. The patients were classified as organic or functional groups. In ETT there was a significant difference between these two groups. These results indicate that neuro-otological tests with video-oculography are very important not only for neurological or neuro-otological patients with nystagmus, but also for psychiatric patients with nystagmus.

Use of Actigraphy for a Rat Behavioural Sleep Study.

Previous studies of animal behavioural sleep is mainly divided into two study types, observation by video recording or counts by sensor, both of which require a complex environment and procedure. An actigraph unit is a commercially available product which can provide non-invasive monitoring human rest/activity cycles. The goal of this study was to evaluate whether actigraphy can be applied for analysing behavioural sleep in rats, since no reports have described utilization of the actigraphy unit for monitoring sleep of small animals. The actigraph unit was held on the chest of eight male rats by a loose elastic belt. The rats spent two days in a normal condition, followed by two days of sleep deprivation. Total counts measured by the actigraph could be clearly divided into two phases, sleep phase and awake phase, when the rats were kept in the normal cage. Next, the rats were moved into the sleep-deviation cage, and the total counts were significantly higher during daytime, indicating the successful induction of sleep deprivation. These results showed that the actigraphy unit monitored rest/activity cycles of rats, which will contribute to making sleep behaviour experiments easier.

The impact of nasal surgery on sleep quality.

OBJECTIVE: Nasal obstruction is considered to be one of the risk factors for obstructive sleep apnea, together with a high arched narrow palate, elongated uvula, malocclusion, and tongue and tonsil size. The impact of nasal obstruction on sleep apnea is controversial, however, and its relation to sleep quality is rarely discussed. The purpose of this study was to investigate the independent effect of nasal obstruction on sleep quality. METHODS: Sixty-nine patients with nasal obstructive symptoms and without sleep apnea episodes were enrolled from September 2018 to August 2019, and compared before and after surgery with thirty-four patients who had benign diseases of the thyroid or parathyroid as a control group, to investigate effects of surgery. Sleep quality was evaluated using the Japanese version of the Pittsburgh Sleep Quality Index (PSQI-J). All cases were reassessed at three months after surgery. RESULTS: The postoperative PSQI scores in the nasal surgery group were significantly lower than the preoperative scores (p < 0.001). In contrast, there was no statistically significance difference between the pre- and postoperative PSQI scores in the neck surgery group. Difference of PSQI scores before and after surgery in the nasal surgery group was significantly higher than the neck surgery group. CONCLUSIONS: This double-arm study suggests that reduction of nasal disfunction with nasal surgery contributes significantly to sleep quality, in patients who may not have noticed their impaired quality of sleep previously because of their long-term nasal symptoms.

A case report of Kuttner tumor mimicking a malignant tumor, leading to overtreatment.

Preoperative diagnosis with multimodal approaches might lead to overtreatment. Cautious understanding of cytology and dynamic contrast-enhanced magnetic resonance imaging is required when a Kuttner tumor is cited as differential diagnosis.

Two cases of exploding head syndrome documented by polysomnography that improved after treatment.

NONE: Exploding head syndrome is a rare sleep disorder, characterized by an explosive feeling in the head, that occurs during the sleep-wake transition. Usually the attacks are painless, but the fear caused by the attack can result in awakening and insomnia when it is generated frequently. It has been suspected that exploding head syndrome is related to emotional stress, because most patients report stressful life situations in periods when attacks are intense and frequent. The benign character and good prognosis of exploding head syndrome are the most likely reasons why it has not become a subject of more extensive neurologic research. Moreover, most of the articles reported symptomatic episodes but a lack of objective physiologic examinations, such as polysomnography, and effective treatment. Here, we report two cases of exploding head syndrome with the attacks documented by polysomnography and our trial treatment.

Cognitive-behavioural therapy for chronic subjective dizziness: Predictors of improvement in Dizziness Handicap Inventory at 6 months posttreatment.

Background: Chronic subjective dizziness (CSD), which was superseded by persistent postural-perceptual dizziness as of 2017, has a great impact on patients' quality of life. Cognitive-behavioural therapy (CBT) is a promising treatment, with demonstrated effectiveness as a CSD treatment; however, no studies have examined positive predictors of its effectiveness in the long term.Aims/objectives: This study aimed to examine predictors of improvement in the Dizziness Handicap Inventory (DHI) in patients with CSD at 6 months after CBT.Materials and methods: Thirty-seven patients with CSD who were recruited from April 2012 to November 2014 and completed group CBT were analysed. Single and multiple regression analyses with forward-backward stepwise model selection method was used to examine the independent predictors of long-term improvement in the change score of DHI.Results: Presence or absence of comorbid anxiety disorders (p = .023) was a significant positive predictive factor for improvement of DHI from pretreatment to 6-month follow-up.Conclusions and significance: The presence of comorbid anxiety disorders predicted considerable improvement of DHI from pretreatment to 6-month follow-up. Group therapy including interoceptive exposure using vestibular rehabilitation, along with psychoeducation and behavioural experiments with graded exposure, may be particularly suitable in treating patients with CSD.

Nystagmus using video-oculography in psychiatric patients.

To evaluate whether nystagmus has clinical significance in psychiatric patients who have functional and/or organic brain dysfunction. We performed gaze, positional and positioning nystagmus tests on 227 patients with psychiatric diseases (144 men, 83 women, with an average age +/- SD of 62.5 +/- 14.0 years) in order to evaluate the frequency and characteristics of nystagmus. Patients were classified according to the underlying disease. Normal control subjects were 107 subjects (26 men, 81 women, with an average age +/- SD of 35.6 +/- 10.0 years). Nystagmus was observed in 56 (24.7%) of 227 cases. Nystagmus was seen in 16 (59.3%) of 27 cases of alcoholism, 14 (22.2%) of 63 cases of organic psychiatric disorders, 25 (20.2%) of 124 cases of schizophrenia, 1 (20.0%) of 5 cases of excited mental retardation, 0 (0.0%) of 7 cases of mood disorders, 0 (0.0%) of 1 case of anxiety disorders and 1 (0.9%) of 107 subjects of normal control. There was a significant difference between psychiatric diseases and normal control. These results indicate that nystagmus may also be a very important clinical finding not only in patients with neurological and neuro-otological diseases, but also in patients with psychiatric diseases.

Normalization of breathing with adenotonsillectomy in Japanese pediatric OSA.

OBJECTIVE: Since reports on surgical results for pediatric obstructive sleep apnea (OSA) in Japan are insufficient for debate, this study aimed to evaluate the feature of Japanese OSA children and surgical result and document whether is obesity and affecting factor similar to non-Asian countries. METHODS: This is a retrospective study. A total of 242 children with OSA at the Department of Otolaryngology and the Good Sleep Center, Nagoya City University Hospital and the Toyohashi Mates Sleep Disorders Center were included in the study. All children underwent pre- and postsurgical polysomnography. OSA was defined as an apnea hypopnea index (AHI) 5 or greater. Pre- and postsurgical respiratory parameters were compared using paired T test. RESULTS: Normalization of breathing after surgery for OSA children was 40% with AHI < 2 and 85% with AHI < 5. Japanese OSA children are not as obese as OSA children in many non-Asian countries. However, the normalization of breathing as a result of surgery in Japanese OSA children does not differ much from non-Asian countries. CONCLUSION: Japanese pediatric OSA that is not normalized by surgery may be affected by factors other than obesity.

Sinonasal inverted papilloma associated with small cell neuroendocrine carcinoma: A case report and literature review of rare malignancies associated with inverted papilloma.

We report a rare case of sinonasal inverted papilloma (IP) associated with small cell neuroendocrine carcinoma (SNEC). To our knowledge, this is the first report to describe SNEC found during the treatment of sinonasal IP. Surgery and five cycles of cisplatin plus etoposide with concurrent intensity modulated radiation therapy were performed. Neither local recurrence nor distant metastasis was noted during 6 years of post-diagnostic follow-up. The prognosis of SNEC is very poor. Treatment planning for sinonasal IP should consider a possible association with this rare but aggressive malignancy, whose treatment is completely different from that of squamous cell carcinoma, a malignancy which is commonly associated with IP. We also performed a PubMed review of the literature to identify the incidence and pathological diagnosis of associated malignancy. Among a total of 5286 cases of sinonasal IP (61 studies), the incidence of associated malignancy was 8.02% in squamous cell carcinoma, 0.19% in transitional cell carcinoma, 0.04% in mucoepidermoid carcinoma, 0.02% in verrucous cell carcinoma and 0.02% in adenocarcinoma. The incidence of associated malignancy was significantly higher in East and Southeast Asia (11.0%) and North America (10.4%) than in Europe (3.9%) (p=0.04 and p=0.03, respectively; T-test).

Nigrostriatal Dopaminergic Dysfunction and Altered Functional Connectivity in REM Sleep Behavior Disorder With Mild Motor Impairment.

Rapid eye movement sleep behavior disorder is parasomnia characterized by symptoms of dream enactment and loss of muscle atonia during rapid eye movement sleep. Mild motor impairment is present in some patients with rapid eye movement sleep behavior disorder and presumed to be a risk factor for conversion to synucleinopathies. The purpose of this study is to identify patients with mild motor impairment by evaluating finger tapping and to investigate its pathophysiology. Twenty-three patients with rapid eye movement sleep behavior disorder and 20 healthy control subjects were recruited in the present study. We accurately evaluated finger tapping including amplitude, peak open, and close speed with a magnetic sensing device and identified patients with mild motor impairment. Moreover, we performed 123I-2ß-carbomethoxy-3ß-(4-iodophenyl) nortropane SPECT and resting state functional MRI. 123I-2ß-carbomethoxy-3ß-(4-iodophenyl) nortropane uptake for each bilateral caudate, anterior putamen, and posterior putamen was calculated and the resting state functional connectivity of sensorimotor network was analyzed. Using finger tapping parameters, we identified eight patients with mild motor impairment. In patients with mild motor impairment, all finger tapping parameters were significantly impaired when compared to patients with normal motor function, while they exhibited no significant differences in Unified Parkinson's Disease Rating Scale part III score. 123I-2ß-carbomethoxy-3ß-(4-iodophenyl) nortropane uptake in the right posterior putamen, bilateral anterior putamen, and caudate was significantly lower when compared to healthy controls or patients with rapid eye movement sleep behavior disorder with normal motor function. These patients also exhibited decreased cortico-striatal functional connectivity and increased cortico-cerebellar functional connectivity when compared to healthy controls or patients with normal motor function. Our results show that mild motor impairment in rapid eye movement sleep behavior disorder evaluated by finger tapping task presented mild nigrostriatal dopaminergic dysfunction as well as alterations in resting state sensorimotor network. Although longitudinal follow up is necessary, such patients may have higher risk of short-term conversion to synucleinopathies.