Unraveling sleep respiratory dysfunction in amyotrophic lateral sclerosis: Beyond the apnea-hypopnea index and sleep-related hypoxia

The timely introduction of non-invasive ventilation (NIV) is extremely relevant in the multidisciplinary management of patients affected by amyotrophic lateral sclerosis (ALS) and is based on the proper identification of red flags for early diaphragmatic exhaustion. Polygraphic sleep recording may provide insightful information on the ongoing respiratory impairment; in particular, atypical breathing patterns need to be recognized, as the application of current guidelines for sleep-related hypoxemia or sleep apnea may be insufficient for detecting early signs of diaphragmatic fatigue. We report the case of a 51-year-old man affected by ALS who was asymptomatic for breathing impairment, but whose nocturnal polysomnographic recording, despite not significant for obstructive sleep apnea nor for conventional hypoventilatory patterns, strongly suggested initial respiratory failure, as lately confirmed by the pulmonary follow-up. We discuss the advantages of including sleep recording in the clinical work-up of patients affected by ALS.

TDP-43 impairs sleep in Drosophila through Ataxin-2-dependent metabolic disturbance

Neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal dementia are associated with substantial sleep disruption, which may accelerate cognitive decline and brain degeneration. Here, we define a role for trans-activation response element (TAR) DNA binding protein 43 (TDP-43), a protein associated with human neurodegenerative disease, in regulating sleep using Drosophila. Expression of TDP-43 severely disrupts sleep, and the sleep deficit is rescued by Atx2 knockdown. Brain RNA sequencing revealed that Atx2 RNA interference regulates transcripts enriched for small-molecule metabolic signaling in TDP-43 brains. Focusing on these Atx2-regulated genes, we identified suppressors of the TDP-43 sleep phenotype enriched for metabolism pathways. Knockdown of Atx2 or treatment with rapamycin attenuated the sleep phenotype and mitigated the disruption of small-molecule glycogen metabolism caused by TDP-43. Our findings provide a connection between toxicity of TDP-43 and sleep disturbances and highlight key aspects of metabolism that interplay with TDP-43 toxicity upon Atx2 rescue.

Tako-Tsubo Syndrome in Amyotrophic Lateral Sclerosis: Single-Center Case Series and Brief Literature Review

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with variable phenotypic expressions which has been associated with autonomic dysfunction. The cardiovascular system seems to be affected especially in the context of bulbar involvement. We describe four new cases of Tako-Tsubo syndrome (TTS) in ALS patients with an appraisal of the literature. We present a late-stage ALS patient with prominent bulbar involvement that presented TTS during hospitalization. We then retrospectively identify three additional ALS-TTS cases reporting relevant clinical findings. TTS cardiomyopathy has been observed in different acute neurological conditions, and the co-occurrence of ALS and TTS has already been reported. Cardiovascular autonomic dysfunctions have been described in ALS, especially in the context of an advanced diseases and with bulbar involvement. Noradrenergic hyperfunction linked to sympathetic denervation and ventilatory deficits coupled in different instances with a trigger event could play a synergistic role in the development of TTS in ALS. Sympathetic hyperfunctioning and ventilatory deficits in conjunction with cardiac autonomic nerves impairment may play a role in the development of TTS in a context of ALS.

Hypothalamus and amyotrophic lateral sclerosis: potential implications in sleep disorders

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease that affects both motor and non-motor functions, including sleep regulation. Emerging evidence suggests that the hypothalamus, a brain region that plays a critical role in sleep-wake regulation, may be involved in the pathogenesis of ALS-related sleep disturbances. In this review, we have summarized results of studies on sleep disorders in ALS published between 2000 and 2023. Thereafter, we examined possible mechanisms by which hypothalamic dysfunctions may contribute to ALS-related sleep disturbances. Achieving a deeper understanding of the relationship between hypothalamic dysfunction and sleep disturbances in ALS can help improve the overall management of ALS and reduce the burden on patients and their families.

Sleep in amyotrophic lateral sclerosis: A systematic review and meta-analysis of polysomnographic findings

BACKGROUND

This study explores the polysomnographic differences between amyotrophic lateral sclerosis (ALS) patients and healthy controls.

METHODS

An electronic literature search was conducted in MEDLINE, EMBASE, All EBM databases, Web of Science, and CNKI from inception to Oct 2022.

RESULTS

Meta-analyses revealed significant reductions in sleep efficiency, total sleep time, N2%, slow wave sleep percentage, minimum SpO₂, and mean SpO₂, and increases in wake time after sleep onset and N1%, sleep latency, rapid eye movement sleep latency, time spent with SpO₂ < 90%, oxygen desaturation index, and apnea hypopnea index in ALS patients compared with controls. Sensitivity analyses showed that some heterogeneity was explained by excluding patients taking medications impacting sleep, whether studies employed an adaptation night, and the use of different PSG scoring rules.

CONCLUSIONS

Significant polysomnographic abnormalities are present in ALS. Our findings underscore the need for a comprehensive PSG assessment of sleep changes in ALS patients. When performing PSG examinations in ALS, whether the patients are taking medication impacting sleep and the scoring system used should be considered.

Sensory Involvement in Amyotrophic Lateral Sclerosis

Although amyotrophic lateral sclerosis (ALS) is pre-eminently a motor disease, the existence of non-motor manifestations, including sensory involvement, has been described in the last few years. Although from a clinical perspective, sensory symptoms are overshadowed by their motor manifestations, this does not mean that their pathological significance is not relevant. In this review, we have made an extensive description of the involvement of sensory and autonomic systems described to date in ALS, from clinical, neurophysiological, neuroimaging, neuropathological, functional, and molecular perspectives.

Cardiovascular autonomic control during application of different modes of noninvasive ventilation in patients affected by amyotrophic lateral sclerosis

BACKGROUND

Cardiovascular events commonly cause death in amyotrophic lateral sclerosis (ALS) even in patients treated by noninvasive ventilation (NIV).

OBJECTIVES

to evaluate autonomic function with the assessment of heart rate variability (HRV) in ALS patients treated by assist pressure control ventilation (APCV) and assist control ventilation (ACV) during sleep.

METHODS

Consecutive ALS patients underwent one polysomnography during APCV and one during ACV. HRV was analyzed both in the total sleep period (from first stage N1 to last awakening) and in a 5-minute period of stable stage N2. Time domain, frequency domain and nonlinear indexes of HRV were measured.

RESULTS

Nineteen patients (age 62.0 ± 8.7, 9F/10 M) were studied. The analysis did not reveal differences in blood gasses between NIV modalities, but a longer expiratory time (3.01±0.6 vs 2.8 ± 0.6 s, respectively APCV vs ACV, p = 0.001) and a lower arousal index (17.5 ± 9.1 vs 23.1 ± 13.9, p = 0.02) during APCV. HRV was indicative of higher vagal activity during APCV, especially in the 5-minute periods. In the total sleep periods, the HRV time domain indexes reflecting parasympathetic activity were positively correlated with the expiratory time and negatively with the inspiratory/expiratory time ratio. Low frequencies were positively, and high frequencies negatively, correlated with inspiratory time. HRV and sleep structure parameters were not correlated, except very low frequencies that were correlated to the arousal index.

CONCLUSIONS

Respiratory influences on autonomic control can be preserved in ALS. The slower breathing pattern during APCV may help to maintain a higher vagal activity. Through this mechanism, in the long-term APCV could more beneficial to ALS patients than ACV.

Perioperative management of patients with amyotrophic lateral sclerosis: A narrative review

Amyotrophic lateral sclerosis, or motor neuron disease, is an uncommon progressive neurological disorder. Professionals working in the perioperative field may encounter patients with amyotrophic lateral sclerosis only rarely. The relevant published literature on amyotrophic lateral sclerosis is broad in scope, but a contemporary review focused on the perioperative period is absent. This structured narrative review seeks to provide a summary of the contemporary management of patients and then focuses on eliciting if there are perioperative management considerations specific to amyotrophic lateral sclerosis that can be optimised. A comprehensive structured narrative literature review, including grey literature searching, indicated worsening ventilatory failure is of prime concern but that patients may present with a broad range of neurological symptoms, and that cardiovascular and cognitive dysfunction specific to amyotrophic lateral sclerosis may exist and be occult. Exacerbation of neuromuscular weakness during the perioperative period is multifaceted and requires the application of a high standard of the core principles of surgical and anaesthetic management of neuromuscular disease. Standard perioperative approaches require rigorous attention and potential exists for significant alteration. There is a potential high risk of postoperative increased morbidity from neurological decline and mortality from pulmonary complications. A meticulous approach to planning preoperative assessment, shared decision-making, intraoperative and postoperative care is required.

MRI Volumetric Analysis of the Thalamus and Hypothalamus in Amyotrophic Lateral Sclerosis

Background: Increasing evidence has shown that amyotrophic lateral sclerosis (ALS) can result in abnormal energy metabolism and sleep disorders, even before motor dysfunction. Although the hypothalamus and thalamus are important structures in these processes, few ALS studies have reported abnormal MRI structural findings in the hypothalamus and thalamus.

Purpose: We aimed to investigate volumetric changes in the thalamus and hypothalamus by using the automatic brain structure volumetry tool AccuBrain^®.

Methods: 3D T1-weighted magnetization-prepared gradient echo imaging (MPRAGE) scans were acquired from 16 patients with ALS with normal cognitive scores and 16 age-, sex- and education-matched healthy controls. Brain tissue and structure volumes were automatically calculated using AccuBrain^®.

Results: There were no significant differences in bilateral thalamic (F = 1.31, p = 0.287) or hypothalamic volumes (F = 1.65, p = 0.213) between the ALS and control groups by multivariate analysis of covariance (MANCOVA). Left and right hypothalamic volumes were correlated with whole-brain volume in patients with ALS (t = 3.19, p = 0.036; t = 3.03, p = 0.044), while the correlation between age and bilateral thalamic volumes tended to be significant after Bonferroni correction (t = 2.76, p = 0.068; t = 2.83, p = 0.06). In the control group, left and right thalamic volumes were correlated with whole-brain volume (t = 4.26, p = 0.004; t = 4.52, p = 0.004).

Conclusion: Thalamic and hypothalamic volumes did not show differences between patients with normal frontotemporal function ALS and healthy controls, but further studies are still needed.

The importance of heart rate variability in predicting cardiac autonomic dysfunction in patients with amyotrophic lateral sclerosis

AIM

Amyotrophic lateral sclerosis (ALS) is a progressive disease characterized by degeneration in the upper and lower motor neurons of the corticospinal tract, brain stem, and spinal cord. Recent studies have revealed that the disease does not present solely with motor neuron involvement. Accordingly, the aim of this study is to investigate the presence of cardiac autonomic impairment in patients diagnosed with ALS.

MATERIAL AND METHOD

A total of 61 patients, who were diagnosed with ALS according to the Revised El Escorial Criteria (R-EEC), were included in this prospective study, in addition to the 29 healthy individuals, who were included in the study as controls. In order to assess the cardiac autonomic involvement, the presence of orthostatic hypotension was investigated, and transthoracic echocardiography and 24-hour electrocardiogram (ECG) using a Holter monitor were performed.

RESULTS

Orthostatic hypotension was detected in 14 (22.2%) patients. Holter electrocardiogram results of the patient group revealed statistically significantly lower heart rate variability (HRV) indicators in the time domain (SDNN, SDANN, SDNN index, rMSSD, and pNN50) and in the frequency domain (high frequency [HF], low frequency [LF], and very low frequency [VLF]) than those of the control group (P < .05).

CONCLUSION

Contrary to the popular opinion, cardiac autonomic dysfunction in patients with ALS can occur at any stage of the disease. Therefore, it is recommended that the patients are evaluated via periodic examinations during the follow-up period for cardiac autonomic involvement.

Sleep in Neurologic Disorders

Sleep is a complex brain state with fundamental relevance for cognitive functions, synaptic plasticity, brain resilience, and autonomic balance. Sleep pathologies may interfere with cerebral circuit organization, leading to negative consequences and favoring the development of neurologic disorders. Conversely, the latter can interfere with sleep functions. Accordingly, assessment of sleep quality is always recommended in the diagnosis of patients with neurologic disorders and during neurorehabilitation programs. This review investigates the complex interplay between sleep and brain pathologies, focusing on diseases in which the association with sleep disturbances is commonly overlooked and whereby major benefits may derive from their proper management.

Assessment of sympathetic sudomotor function in amyotrophic lateral sclerosis with electrochemical skin conductance

OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is now recognized as a multisystem neurodegenerative disorder, comprising autonomic dysfunction. We aimed to assess sudomotor function in ALS by measuring the electrochemical skin conductance (ESC).

METHODS

Thirty-one ALS patients [median age of 62 years (1st-3rd interquartile range - IQR, 56-72), male 71%] were prospectively compared with 29 healthy controls, matched for age and sex. We analysed ESC results from hands and feet, bilaterally.

RESULTS

A total of 120 ESC recordings were obtained. Hands and feet ESC measurements were significantly lower in patients compared with controls [64 μS (1st-3rd IQR, 57-58) versus 78 μS (1st-3rd IQR, 70.5-84), p < 0.001 and 76 μS (1st-3rd IQR, 68-83) versus 81 μS (1st-3rd IQR, 78-86), p = 0.008, respectively]. In ALS group, no differences were observed between spinal and bulbar-onset forms for hands and feet results (p > 0.05). Hands and feet ESC measurements did not correlate also with disease duration, total ALSFRS-R scale, or ALSFRS-R progression rate (all p > 0.05).

CONCLUSION

ESC is a non-invasive, fast and quantitative method suitable for assessing sudomotor function. ALS patients revealed a decreased function in upper and lower extremities.

SIGNIFICANCE

Sudomotor dysfunction is part of the ALS manifestations.

Disorders of sleep and wakefulness in amyotrophic lateral sclerosis (ALS): a systematic review

Disorders of sleep and wakefulness are common among neurodegenerative diseases. While amyotrophic lateral sclerosis (ALS) predominately manifests as motor symptoms, there is emerging evidence that disruptions to sleep and wakefulness also occur. This systematic review aims to report the most common disorders of sleep and wakefulness in ALS. We conducted a qualitative systematic review as per PRISMA guidelines and searched literature assessing the association between disorders of sleep and wakefulness with ALS using the PubMed and Medline database. Overall, 50-63% of patients with ALS have poor sleep quality as reported using the Pittsburgh Sleep Quality Index Questionnaire (PSQI). A higher proportion of ALS patients are categorized as poor sleepers, however there is conflicting evidence as to whether patients with ALS are more likely to exhibit excessive daytime sleepiness. Of the studies that utilized polysomnography, all reported various degrees of impairment to sleep microstructure and architecture among ALS patients. In future, longitudinal clinical studies will be essential for establishing the significance of impaired sleep in ALS. Future studies are also needed to establish whether the self-reported measures of poor sleep and impairment to sleep architecture occurs as a direct consequence of the disease, whether they are an early manifestation of the disease, and/or if they contribute to the neurodegenerative process.

Sleep and Sleep Disruption in Amyotrophic Lateral Sclerosis

PURPOSE OF REVIEW

In amyotrophic lateral sclerosis (ALS), sleep disruption is frequently present and substantially adds to disease burden. This review aims to summarize current knowledge on causes, pathophysiology, and treatment of sleep disturbances in ALS.

RECENT FINDINGS

Motor neuron degeneration and muscle weakness may lead to muscle cramps, pain, spasticity, immobilization, restless legs, sleep-disordered breathing, and difficulties to clear secretions. Furthermore, existential fears and depression may promote insomnia. Sleep-disordered breathing, and nocturnal hypoventilation in particular, requires ventilatory support which meaningfully prolongs survival and improves health-related quality of life albeit respiratory failure is inevitable. Early indication for non-invasive ventilation can be achieved by inclusion of capnometry in diagnostic sleep studies. Sleep disruption is extremely common in ALS and may arise from different etiologies. The absence of causative therapeutic options for ALS underlines the importance of symptomatic and palliative treatment strategies that acknowledge sleep-related complaints.

The vestibulo-masseteric reflex and the acoustic-masseteric reflex: a reliability and responsiveness study in healthy subjects

The vestibulo-masseteric reflex (VMR or p11 wave), the acoustic-masseteric reflex (AMR or p1/n21 wave) and the mixed vestibulo-cochlear p11/n21 potential are responses of masseter muscles to sound that can be employed to evaluate brainstem function. This study was aimed at establishing the test-retest reliability and responsiveness of these reflex parameters according to the type of electrode configuration. Twenty-two healthy volunteers (M:F = 11:11; mean age 25.3 ± 5.2 years) participated in two testing sessions separated by one week. Zygomatic and mandibular montages were compared following unilateral and bilateral stimulations. For reliability purposes, intraclass correlation coefficient (ICC), coefficient of variation of the method error (CVME) and standard error of measurement (SEM) were calculated. The minimal detectable difference (MDD) was also determined as a measure of responsiveness. Both VMR (p11 wave) and AMR could be consistently evoked from test to retest, although the frequency rate was significantly higher (all p values ≤ 0.009) with zygomatic (VMR: 97.7-100%; AMR: 86.9-97.6%) than mandibular montage (VMR: 84.7-89.8%; AMR: 65.0-67.8%), with no significant differences between unilateral and bilateral stimulations. Good-to-excellent reliability and responsiveness (high ICC, low CV_ME, SEM and MDD scores) were detected for corrected amplitudes and peak latencies for all reflex responses, whereas raw amplitudes were associated to poor reliability. The reliability of the zygomatic montage proved superior to the mandibular montage for all reflex responses. Given their high test-retest consistency and capability to study different features of the reflex arch, both peak latencies and corrected amplitudes should be reported and considered in the interpretation of reflex testing results.

Circadian sleep/wake-associated cells show dipeptide repeat protein aggregates in C9orf72-related ALS and FTLD cases

Motor-, behavior- and/or cognition-related symptoms are key hallmarks in patients with amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) with TDP-43 pathology (FTLD-TDP), respectively. It has been reported that these patients also experience sleep disturbances, which might implicate a disturbed circadian rhythm of the sleep/wake cycle. It remains unknown, however, whether cells involved in the circadian sleep/wake cycle are affected by ALS- and FTLD-related neuropathological changes including phosphorylated TDP-43 (pTDP-43) aggregates and dipeptide repeat protein (DPR) inclusions resulting from the C9orf72 hexanucleotide repeat expansion. Immunohistochemistry for DPR and pTDP-43 pathology was performed in post-mortem hypothalamus and pineal gland tissue of patients with ALS and/or FTLD-TDP with and without the C9orf72 repeat expansion and healthy controls. Circadian sleep/wake-associated cells, including pinealocytes and hypothalamic neurons related to the suprachiasmatic nucleus (SCN), were microscopically assessed. We observed numerous DPR inclusions (poly(GA), poly(GP), poly(GR) and poly(PR)) in the pinealocytes and few poly(GA) inclusions in the SCN-related neurons in C9orf72-related ALS and/or FTLD-TDP cases. These circadian sleep/wake-associated cells, however, were devoid of pTDP-43 pathology both in C9orf72- and nonC9orf72-related ALS and/or FTLD-TDP cases. Our neuropathological findings show that pinealocytes and, to a lesser extent, SCN-related neurons are affected by DPR pathology. This may reflect an involvement of these cells in sleep/wake disturbances observed in ALS and/or FTLD-TDP patients.