Association of dysphagia severity in multiple system atrophy with the specific binding ratio on dopamine transporter SPECT.

OBJECTIVE: Dysphagia in multiple system atrophy (MSA) is life-threatening and is caused by parkinsonism with cerebellar ataxia as a contributing factor. The present study investigated the relationship between dysphagia severity in MSA and the specific binding ratio (SBR) on dopamine transporter (DaT) SPECT using the Hyodo score, a qualitative scale for use with fiberoptic endoscopic evaluation of swallowing (FEES). METHODS: Hyodo score's ability to predict aspiration during a FEES examination of 88 patients with MSA was first tested. Then the clinical characteristics, Hyodo score, and SBR of patients with either predominant parkinsonism (MSA-P; n = 11) or cerebellar ataxia (MSA-C; n = 25) who underwent FEES and DaT SPECT simultaneously were compared. RESULTS: Logistic regression demonstrated that the Hyodo score was a significant predictive factor of aspiration (p = 0.003). The MSA-P group had a significantly higher Hyodo score (p = 0.026) and lower SBR (p = 0.011) than the MSA-C group while neither group demonstrated any significant difference in disease duration at the FEES examination. Linear regression demonstrated a significant, inverse correlation between the Hyodo score and SBR in the MSA-P (p = 0.044; r = -0.616) and MSA-C (p = 0.044; r = -0.406) groups. When the effect of SBR was removed by analysis of covariance, no significant difference in the Hyodo score remained between the groups. CONCLUSIONS: Our results suggested an association between presynaptic changes in nigrostriatal dopaminergic neurons and dysphagia severity in MSA which largely contributes to the difference in dysphagia severity between MSA-P and MSA-C.

Diagnostic utility of Gold Coast criteria for amyotrophic lateral sclerosis in Asia.

Objective: This study aimed to reveal the diagnostic utility of Gold Coast (GC) criteria in Japanese patients with amyotrophic lateral sclerosis (ALS) by comparing the sensitivity/specificity with revised El Escorial (R-EE) and Awaji criteria, because its utility has not been studied in Asian ALS. Methods: Consecutive 639 patients (529 with ALS and 110 with ALS mimics), who were suspected of ALS and referred to three Japanese ALS centers, were enrolled. Diagnostic accuracy and characteristics of false positive and negative in GC criteria were compared with those of the Awaji and R-EE criteria. Patients were categorized as definite, probable or possible ALS according to each criterion. Results: The sensitivity of GC criteria (96.8%, 95% confidence interval [CI]: 95.3-98.3%) was higher than that of Awaji (89.6%, 95% CI: 87.0-92.2%) and R-EEC (89.2, 95% CI: 86.6-91.8%) criteria (both, p < 0.001). The specificity was also higher with GC criteria (77.3%, 95% CI: 69.5-85.1%) than Awaji (65.5%, 95% CI: 56.6-74.4%) and R-EEC (66.4, 95% CI: 57.6-75.2%) criteria (both, p < 0.01). Using GC criteria, patients with cervical spondylosis and Parkinson's syndrome tended to be diagnosed with ALS (i.e. "false positive"). Additionally, ALS patients diagnosed only by GC criteria less frequently had upper motor neuron (UMN) signs, compared with the other two criteria. Conclusion: Gold Coast criteria improve diagnostic accuracy for ALS in an Asian population, especially in patients with subtle UMN signs.

High doses of opioids usage for amyotrophic lateral sclerosis patients with non-invasive ventilation.

INTRODUCTION: While opioids have been found to be useful in relieving suffering in amyotrophic lateral sclerosis (ALS), there is a lack of evidence concerning how and how much to use them in practice. This study was conducted to clarify how opioids were used for patients with ALS. METHODS: We performed a retrospective case-based analysis at a single tertiary neurology center in Tokyo from 2010 to 2018. We enrolled patients with ALS who had died before the end of 2018. We examined the opioid dosage equivalent of morphine hydrochloride and patients' clinical backgrounds, focusing on ventilatory support. RESULTS: Morphine was administered in 110 patients with ALS, and 84 were followed up until their death. Of these 84 patients, 57 (69.9%) did not use mechanical ventilation until death (no-MV group), and 21 (22.9%) utilized only non-invasive ventilation (NIV group). Final morphine dosage in the NIV group was significantly higher (mean 65.7 mg [SD 54.6], range 10-200 mg) than in the no-MV group (mean 31.7 mg [SD 26.9], range 0-120 mg; p = 0.015, Welch's t-test). The NIV group needed psychotropic drugs more frequently than the no-MV group (62% [n = 13] vs. 35% [n = 20]). CONCLUSION: Patients in the NIV group used opioids for a statistically significantly longer time and at a higher dose than those in the no-MV group. Symptom control with opioids alone may be difficult, and the development of multifaceted evaluation and care is desirable.

Somatosensory pathway dysfunction in patients with amyotrophic lateral sclerosis in a completely locked-in state.

OBJECTIVE: To investigate somatosensory pathway function in patients with amyotrophic lateral sclerosis (ALS) dependent on invasive ventilation and in a completely locked-in state (CLIS). METHODS: We examined median nerve somatosensory evoked potentials (SEPs) in 17 ALS patients in a CLIS, including 11 patients with sporadic ALS, one with familial ALS with genes not examined, four with a Cu/Zn superoxide-dismutase-1 (SOD1) gene variant (Val118Leu, Gly93Ser, Cys146Arg), and one with a fused-in-sarcoma gene variant (P525L). We evaluated N9, N13, N20 and P25, and central conduction time (CCT); the data were compared with those of 73 healthy controls. RESULTS: N20 and N13 were abolished in 12 and 10 patients, and their latencies was prolonged in four and three patients, respectively. The CCT was prolonged in five patients with measurable N13 and N20. Two patients with SOD1 gene mutations had absent or slightly visible N9. Compared to the CCT and latencies and amplitudes of N13 and N20 in the controls, those in the patient cohort were significantly abnormal. CONCLUSIONS: The central somatosensory pathway is severely involved in patients with ALS in a CLIS. SIGNIFICANCE: Our findings suggest that median nerve SEP cannot be utilized for communication in patients with ALS in a CLIS.

Sensory Gating during Voluntary Finger Movement in Amyotrophic Lateral Sclerosis with Sensory Cortex Hyperexcitability.

Cortical responses in somatosensory evoked potentials (SEP) are enhanced in patients with amyotrophic lateral sclerosis (ALS). This study investigated whether sensory gating is involved in the pathophysiology of sensory cortical hyperactivity in ALS patients. The median nerve SEP was recorded at rest and during voluntary finger movements in 14 ALS patients and 13 healthy control subjects. The parietal N20, P25, and frontal N30 were analyzed, and sensory gating was assessed by measuring the amplitude of each component during finger movement. The amplitudes of the N20 onset-peak, N20 peak-P25 peak, and N30 onset-peak were higher in ALS patients than in controls. Nonetheless, there were no significant differences in the amplitude reduction ratio of SEPs between patients and controls. There was a significant correlation between the baseline amplitudes of the N20 onset-peak or N20 peak-P25 peak and their gating ratios in patients with ALS. Our findings indicate that the excitability of the primary sensory cortex and secondary motor cortex is enhanced in ALS, while sensory gating is preserved in the early stages of ALS. This result suggests that enhanced SEP is caused by the hyperexcitability of the primary sensory and secondary motor cortices but not by the dysfunction of inhibitory mechanisms during voluntary movements.

Exacerbation of Thymoma-Associated Myasthenia Gravis Following Efgartigimod Treatment Related to Anti-acetylcholine Receptor Antibody Overshoot: A Report of Two Cases.

Myasthenia gravis (MG), a chronic, autoimmune disease affecting the neuromuscular junction, arises from various autoantibodies, including those against the acetylcholine receptor (AChR). Recently, efgartigimod, a human IgG1 antibody Fc fragment engineered to reduce the pathogenic IgG autoantibody level, was developed as a treatment for MG. However, the long-term effects of the treatment are still unclear. The present report describes two novel cases of thymoma-associated MG exacerbation following efgartigimod treatment related to anti-AChR antibody overshoot. Both cases shared certain characteristics, including anti-AChR antibody positivity and post-thymectomy status. After a few cycles of efgartigimod treatment, their MG deteriorated, and their anti-AChR antibody titer exceeded the level before efgartigimod therapy. Prior studies show that anti-AChR antibody titer does not correlate with the disease severity of MG. However, previous studies have reported antibody overshoot following plasma exchange, which, like efgartigimod, reduces the level of plasma IgG and autoantibodies. Thus, MG exacerbation with anti-AChR antibody overshoot may be an adverse effect of both efgartigimod and plasma exchange. When clinical symptoms in patients with thymoma-associated MG receiving efgartigimod deteriorate despite low IgG, assessing the anti-AChR antibody level can be important for reconsidering the treatment strategy.

The difference in the diaphragmatic physiological measures between inspiratory and expiratory phases in ALS.

INTRODUCTION: We aimed to clarify the differences in static and dynamic diaphragm parameters between the expiratory and inspiratory phases in amyotrophic lateral sclerosis (ALS). METHODS: Twenty patients with early-stage ALS and 16 healthy controls were enrolled in the study. We measured the amplitudes of compound muscle action potential (phCMAP) by electrical stimulation of the phrenic nerve and the zone of apposition wall thickness of the diaphragm (DT) using ultrasonography. We analyzed the differences in phCMAP (∆phCMAP) and DT (∆DT) between the end-inspiratory and end-expiratory phases and their correlation with forced vital capacity (FVC). RESULTS: The ΔphCMAP (mean 129.7 ± SD 204.7 µV) and ∆DT (0.80 ± 0.88 cm) in patients were significantly smaller than those in controls (348.6 ± 247.7 µV, p = 0.0003 and 1.89 ± 1.10 cm, p = 0.0002, respectively). Although ∆DT was significantly correlated with FVC, we found no correlation between ∆phCMAP and FVC. The phCMAP was paradoxically smaller during inspiration than during expiration in 35% of patients but in none of the controls. CONCLUSION: Dynamic parameters of the diaphragm were abnormal in early-stage ALS. The paradoxical reduction in phCMAP during inspiration may reflect early respiratory dysfunction. Assessment of dynamic abnormalities of the diaphragm may provide helpful information for respiratory management in patients with ALS.

Body Weight Gain Is Associated with the Disease Stage in Advanced Amyotrophic Lateral Sclerosis with Invasive Ventilation.

We investigated the incidence of weight gain and its related factors in patients with amyotrophic lateral sclerosis (ALS) who underwent tracheostomy and invasive ventilation (TIV). Seventy-eight patients with ALS and TIV were enrolled and followed up prospectively. We clarified the clinical profiles of patients with increased weight following TIV and examined chronological variations in their body mass index (BMI), energy intake, and serum albumin levels. Post follow-up, we determined their disease stage according to their communication impairment (stage I to V) and investigated factors associated with BMI increase following TIV. Patients with a post-TIV BMI increase ≥1.86 kg/m2 demonstrated a higher incidence of ophthalmoplegia (76.2%), total quadriplegia (61.9%), severe communication impairment (stage V; 33.3%), and hypoalbuminemia than those with a BMI increase <1.86 kg/m2. Patients with stage V communication impairment exhibited a larger and faster BMI decrease before TIV (mean -4.2 kg/m2 and -2.5 kg/m2/year, respectively); a larger BMI increase (mean +4.6 kg/m2) following TIV, despite lower energy intake; and lower albumin levels post follow-up than those with lower-stage communication impairment. Multilevel linear regression analysis demonstrated an independent association between communication impairment stages (stage V) and a post-TIV BMI increase (p = 0.030). Weight gain and hypoalbuminemia during TIV in patients with ALS were associated with the disease stage and may be attributable to the neurodegenerative processes that are peculiar to ALS.

Enlarged high frequency oscillations of the median nerve somatosensory evoked potential and survival in amyotrophic lateral sclerosis.

OBJECTIVE: A large N20 and P25 of the median nerve somatosensory evoked potential (SEP) predicts short survival in amyotrophic lateral sclerosis (ALS). We investigated whether high frequency oscillations (HFOs) over N20 are enlarged and associated with survival in ALS. METHODS: A total of 145 patients with ALS and 57 healthy subjects were studied. We recorded the median nerve SEP and measured the onset-to-peak amplitude of N20 (N20o-p), and peak-to-peak amplitude between N20 and P25 (N20p-P25p). We obtained early and late HFO potentials by filtering SEP between 500 and 1 kHz, and measured the peak-to-peak amplitude. We followed up patients until endpoints (death or tracheostomy) and analyzed the relationship between SEP or HFO amplitudes and survival using a Cox analysis. RESULTS: Patients showed larger N20o-p, N20p-P25p, and early and late HFO amplitudes than the control values. N20p-P25p was associated with survival periods (p = 0.0004), while early and late HFO amplitudes showed no significant association with survival (p = 0.4307, and p = 0.6858, respectively). CONCLUSIONS: The HFO amplitude in ALS is increased, but does not predict survival. SIGNIFICANCE: The enlarged HFOs in ALS might be a compensatory phenomenon to the hyperexcitability of the sensory cortex pyramidal neurons.

[A proposal of a novel palliative care scale and analysis of suffering in amyotrophic lateral sclerosis].

OBJECTIVE: We proposed a novel palliative care scale (Amyotrophic Lateral Sclerosis Palliative Care Scale: ALSPCS) for patients with ALS, and analyzed the suffering reported by patients. METHODS: Thirty-one patients participated in the study. The ALSPCS has 15 items to evaluate physical and psychological suffering; patients scored their subjective suffering on a scale of 0-5 for each item. This study analyzed 13 of 15 items. RESULTS: The mean scores obtained from the patients were as follows: 'dyspnea', 2.5; 'pain', 2.4; 'restlessness', 2.4; 'thirst', 3.0; 'burning sensation', 2.0; 'choking', 2.0; 'nausea', 0.4; 'constipation', 1.5; 'insomnia', 2.5; 'anxiety', 3.5; 'loneliness', 2.4; 'irritation', 2.1; and 'communication difficulty', 2.3. Multiple correlation analysis using Spearman's rank correlation coefficient showed significant correlations of dyspnea with restlessness, thirst, burning sensation and anxiety; of restlessness with dyspnea, thirst, loneliness and irritation; and of anxiety with dyspnea, thirst and loneliness (P < 0.0038 after Bonferroni's correction). In the principal component analysis, every item showed a positive loading value in the first principal component. Dyspnea, restlessness, thirst, anxiety, loneliness and irritation had loading values >0.7; thus, these symptoms might be the main features in ALS patients. The total scores or each ALSPCS score showed no significant association with post-assessment survival period. CONCLUSION: This study, using ALSPCS, showed that the subjective suffering of ALS patients was variable and strongly correlated with each other. Appropriate and comprehensive assessment of physical and psychological affliction with ALSPCS could be potentially useful in verifying the effectiveness of palliative care for end-of-life stage ALS patients in the future.

Contradictory Responses to the COVID-19 Pandemic in Amyotrophic Lateral Sclerosis Patients and Their Families and Caregivers in Japan.

Objective The coronavirus disease 2019 (COVID-19) pandemic has resulted in a shortage of medical resources, including ventilators, personal protective equipment, medical staff, and hospital beds. We investigated the impact of COVID-19 in amyotrophic lateral sclerosis (ALS) patients, their families, caregivers, and medical experts. Methods We conducted a nationwide ALS webinar about COVID-19 in May 2020 and sent a questionnaire to those enrolled. Results A total of 135 participants (31 ALS patients; 23 families and caregivers of ALS patients; 81 medical experts) responded to this cross-sectional self-report questionnaire. The results showed that tracheostomy and invasive ventilation (TIV) was used in 22.6% of ALS patients, whereas 77.4% of ALS patients were not under TIV. Among non-TIV patients (n=24), 79.2% did not want TIV in the future. However, 47.4% of non-TIV patients not wanting a tracheostomy in advanced stages replied that they would want an emergency tracheostomy if they developed COVID-19-related pneumonia. These results suggest that ALS patients may be receptive to emergency treatments for reasons other than ALS. In addition, approximately half of the ALS patients agreed with the policy of not ventilating the elderly or ALS patients in case of a ventilator shortage. Furthermore, compared with medical experts, few ALS patients reported that the chance for ALS patients to obtain work was higher due to the increasing availability of remote work. Conclusions This survey indicates that the COVID-19 pandemic might be associated with increased distress about access to care and work, inducing contradictory responses and potential hopelessness among ALS patients.

[Current status and future vision of nutrition support team at the neurological hospital].

The effect of malnutrition on intractable neurological diseases, including neurodegenerative diseases, is variable. Nutritional status is dependent on various factors such as disease characteristics; various symptoms including dysphagia, respiratory dysfunction, motor weakness, muscle rigidity, involuntary movement, and ataxia; and changes in energy metabolism caused by diseases and its stage. Nutritional therapy for patients with intractable neurological diseases requires the provision of tailor-made supports for individual patients based on sharing of knowledge and experience in multidisciplinary members. Evidence on nutritional management in the field of neurology is limited compared to that in the fields of surgery and internal medicine. This article thus aimed to describe the activities of the nutrition support team (NST) at our hospital that is specialized in intractable neurological diseases and the knowledge obtained through the activities.

Relationship between EMG-detected and ultrasound-detected fasciculations in amyotrophic lateral sclerosis: A prospective cohort study.

OBJECTIVES: Fasciculation potentials (FP) are an important consideration in the electrophysiological diagnosis of ALS. Muscle ultrasonography (MUS) has a higher sensitivity in detecting fasciculations than electromyography (EMG), while in some cases, it is unable to detect EMG-detected fasciculations. We aimed to investigate the differences of FP between the muscles with and without MUS-detected fasciculations (MUS-fas). METHODS: Thirty-one consecutive patients with sporadic ALS were prospectively recruited and in those, both needle EMG and MUS were performed. Analyses of the amplitude, duration, and number of phases of EMG-detected FPs were performed for seven muscles per patient, and results were compared between the muscles with and without MUS-fas in the total cohort. RESULTS: The mean amplitude and phase number of FP were significantly lower in patients with EMG-detected FP alone (0.39 ±â€¯0.25 mV and 3.21 ±â€¯0.88, respectively) than in those with both FP and MUS-fas (1.22 ±â€¯0.92 mV and 3.74 ±â€¯1.39, respectively; p < 0.0001 and p = 0.017, Welch's t-test). CONCLUSION: Small FP may be undetectable with MUS. MUS cannot replace EMG in the diagnostic approach for ALS. SIGNIFICANCE: Clinicians should use a combination of EMG and MUS for the detection and quantitative analysis of fasciculation in ALS.

Progressive deterioration of sensory cortex excitability in advanced amyotrophic lateral sclerosis with invasive ventilation.

We describe a patient with sporadic amyotrophic lateral sclerosis (ALS) who showed progressive deterioration of sensory cortex excitability at the advanced stage, while using invasive ventilation. At the time of diagnosis, the patient showed enlarged N20 of the median nerve somatosensory evoked potential (SEP). Following ventilator use through tracheostomy, the patient gradually fell into a totally locked-in state for four years and the N20 showed progressive deterioration in the amplitude, which finally led to its loss. Magnetic resonance imaging (MRI) showed frontotemporal and mild parietal cortex atrophy, subcortical white matter hyperintensity and brainstem atrophy suggesting the involvement of the central sensory pathways. MRI and flash visual evoked potentials revealed that the occipital lobe was well-preserved throughout the course of the disease. This is the first case report of a physiological demonstration of multisystem neurodegeneration involving the central sensory pathway in a patient with advanced ALS and invasive ventilation use.

Body weight variation predicts disease progression after invasive ventilation in amyotrophic lateral sclerosis.

Weight loss is an independent predictor of survival in the early stages of amyotrophic lateral sclerosis (ALS). However, the effects of weight variations on the functional prognosis after tracheostomy and invasive ventilation (TIV) in ALS remain unknown. This prospective cohort study aimed to investigate the relationship between weight loss before TIV and disease progression after TIV in ALS patients. Sixty ALS patients with TIV were enrolled and classified into subgroups based on the rate of decline in body mass index, from onset to TIV utilization (ΔBMI). During follow-up, we assessed the patients for presence of communication impairments, ophthalmoplegia, total quadriplegia, mouth opening disability, and dysuria. We analyzed the relationship between ΔBMI and the communication stage or motor disabilities. The log-rank test showed that patients with a ΔBMI ≥ 1.7 kg/m2/year showed a shorter period of preserved communication ability (p = 0.0001), shorter time to develop ophthalmoplegia (p = 0.0001), total quadriplegia (p < 0.0001), mouth opening disability (p < 0.0001), and dysuria (p = 0.0455). Cox multivariate analyses showed that a larger ΔBMI was an independent prognostic factor for the early development of ophthalmoplegia (p = 0.0400) and total quadriplegia (p = 0.0445). Weight loss in the early stages of ALS predicts disease progression in patients with advanced stages of ALS using TIV.

Prognostic significance of body weight variation after diagnosis in ALS: a single-centre prospective cohort study.

BACKGROUND: Body weight reduction after disease onset is an independent predictor of survival in amyotrophic lateral sclerosis (ALS), but significance of weight variation after diagnosis remains to be established. OBJECTIVE: To investigate weight variation after diagnosis and its prognostic significance in patients with ALS as a prospective cohort study. METHODS: Seventy-nine patients with ALS were enrolled in this study. At the time of diagnosis and about 1 year later, we evaluated the following parameters: age, sex, onset age, onset region, body mass index (BMI) and premorbid BMI, forced vital capacity and the revised ALS functional rating scale. Annual BMI decline rates (∆BMI) from onset to diagnosis and from diagnosis to about 1 year later were calculated. Patients were followed to the endpoints (death or tracheostomy), and the relationships between ∆BMIs and survival were investigated. RESULTS: Patients with post-diagnostic ∆BMI ≥ 2.0 kg/m2/year showed shorter survival length than those with < 2.0 kg/m2/year (log-rank test, p < 0.0001), and multivariate analysis using the Cox model revealed post-diagnostic ∆BMI as an independent prognostic factor. No correlation was identified between pre- and post-diagnostic ∆BMIs. Female patients with post-diagnostic ∆BMI < pre-diagnostic ∆BMI showed longer survival than those with the opposite ∆BMI trend (log-rank test, p = 0.0147). Female patients with post-diagnostic weight increase showed longer survival than those with weight decrease (log-rank test, p = 0.0228). CONCLUSION: Body weight changes after diagnosis strongly predicts survival in ALS, and weight gain after diagnosis may improve survival prognosis, particularly in female ALS patients.

Sensory cortex hyperexcitability predicts short survival in amyotrophic lateral sclerosis.

OBJECTIVE: To investigate somatosensory cortex excitability and its relationship to survival prognosis in patients with amyotrophic lateral sclerosis (ALS). METHODS: A total of 145 patients with sporadic ALS and 73 healthy control participants were studied. We recorded compound muscle action potential and sensory nerve action potential of the median nerve and the median nerve somatosensory evoked potential (SEP), and we measured parameters, including onset-to-peak amplitude of N13 and N20 and peak-to-peak amplitude between N20 and P25 (N20p-P25p). Clinical prognostic factors, including ALS Functional Rating Scale-Revised, were evaluated. We followed up patients until the endpoints (death or tracheostomy) and analyzed factors associated with survival using multivariate analysis in the Cox proportional hazard model. RESULTS: Compared to controls, patients with ALS showed a larger amplitude of N20p-P25p in the median nerve SEP. Median survival time after examination was shorter in patients with N20p-P25p ≥8 µV (0.82 years) than in those with N20p-P25p <8 µV (1.68 years, p = 0.0002, log-rank test). Multivariate analysis identified a larger N20p-P25p amplitude as a factor that was independently associated with shorter survival (p = 0.002). CONCLUSION: Sensory cortex hyperexcitability predicts short survival in patients with ALS.

Mitophagy in three cases of immune-mediated necrotizing myopathy associated with anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase autoantibodies: ultrastructural and immunohistochemical studies.

Immune-mediated necrotizing myopathy (IMNM) associated with anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) autoantibodies occurs in patients both with and without history of statin-intake. The mechanisms of muscle fiber degeneration in this condition remain unknown. We studied pathological changes in muscle biopsies from three patients lacking history of statin-intake. Ultrastructural observations showed accumulation of degenerating mitochondria, glycogen granules and autophagic vacuoles, forming large composites in three cases, along with various nonspecific changes. The autophagic vacuoles often contained remnants of mitochondria, indicating mitophagy. Furthermore, upregulation of B-cell lymphoma 2/adenovirus E1B 19 kD-interacting protein 3 (BNIP3), a protein involved in mitophagy, was observed in two cases examined. In three cases of sporadic inclusion body myositis, two polymyositis, and three IMNM with anti-signal recognition particle antibody, BNIP3 was upregulated less frequently, and ultrastructural change of mitophagy was rarely seen. These findings suggested that mitophagy plays an important role in muscle fiber degeneration in IMNM with anti-HMGCR autoantibodies.