The NEALS primary lateral sclerosis registry

The Role of Gastrostomy and Noninvasive Ventilation in Primary Lateral Sclerosis

INTRODUCTION/AIMS

Literature on the role of gastrostomy and noninvasive ventilation (NIV) in primary lateral sclerosis (PLS) is limited. We aim to investigate whether PLS patients develop dysphagia requiring feeding tubes or respiratory failure necessitating NIV.

METHODS

We conducted a retrospective study of PLS patients with a definite diagnosis followed at our center (1994-2024). Patients with marked dysphagia (score < 3 on Question 3 of the ALSFRS-R) received a recommendation for gastrostomy and were divided into two groups: G1/G2 (accepted/declined gastrostomy). We investigated NIV indications due to respiratory failure and compared these patients (G3) to those without respiratory impairment (G4). Demographic, clinical, and neurophysiological data were collected and compared.

RESULTS

Forty-eight patients had a definite diagnosis of PLS. Gastrostomy was recommended to 18 (37.5%), yet only 7 patients (38.9%-G1) consented. The median time to gastrostomy was 77 months. Total survival and survival post-gastrostomy recommendation were not different between G1 and G2. Six PLS patients (12.5%-G3) developed respiratory failure and initiated NIV (median of 63 months). At 63 months, G3 had significantly lower median forced vital capacity (65% vs. 99%; p < 0.001) and phrenic nerve amplitude (0.43 vs. 0.75 mV; p = 0.039), but a greater ALSFRS-R slope (0.34 vs. 0.14; p = 0.046) and shorter survival (35 vs. 94.9 months; p = 0.009) compared to G4.

DISCUSSION

Dysphagia requiring gastrostomy was common in our PLS cohort, but survival after gastrostomy recommendation did not differ between groups. Patients who developed respiratory impairment may represent a distinct group with faster disease progression and shorter survival. Our findings may contribute to a deeper understanding and improved management of PLS.

Neuroglia in neurodegeneration: Amyotrophic lateral sclerosis and frontotemporal dementia

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are devastating neurodegenerative diseases sharing significant pathologic and genetic overlap, leading to consider these diseases as a continuum in the spectrum of their pathologic features. Although FTD compromises only specific brain districts, while ALS involves both the nervous system and the skeletal muscles, several neurocentric mechanisms are in common between ALS and FTD. Also, recent research has revealed the significant involvement of nonneuronal cells, particularly glial cells such as astrocytes, oligodendrocytes, microglia, and peripheral immune cells, in disease pathology. This chapter aims to provide an extensive overview of the current understanding of the role of glia in the onset and advancement of ALS and FTD, highlighting the recent implications in terms of prognosis and future treatment options.

Could PLS represent a UMN-predominant ALS syndrome?

Primary lateral sclerosis (PLS) is a motor neuron condition marked by pure upper motor neuron (UMN) degeneration. PLS represents around 3% of all motor neuron diseases. Classically the prognosis of PLS is less severe than those of amyotrophic lateral sclerosis (ALS). This explains the necessity to distinguish both conditions as early as possible. The key hallmark between the two diseases is the involvement of the lower motor neuron (LMN) system which is classically considered spared in PLS contrary to ALS. Although it seemed clinically easy to distinguish PLS from ALS with the aid of clinical and complementary examinations, there is a large body of evidence highlighting that the LMN system might be impaired in PLS. This led us to suggest that PLS might be considered as an almost pure UMN ALS phenotype.

Autonomic impairment in primary lateral sclerosis

PURPOSE

Prior studies reported evidence of autonomic involvement in motor neuron disease and suggested more severe dysfunction in upper motor neuron predominant syndromes. Hence, we sought to characterize autonomic impairment in primary lateral sclerosis.

METHODS

Neurological evaluations, thermoregulatory sweat tests, and autonomic reflex screens were analyzed retrospectively in 34 primary lateral sclerosis patients (28 definite and 6 probable). Patients with other potential causes of autonomic failure and patients with autonomic testing results compromised by artifact were excluded.

RESULTS

A total of 17 patients reported autonomic symptoms. Orthostatic lightheadedness was most frequent (8 patients), followed by bladder (7), bowel (5), and erectile dysfunction (3). The autonomic reflex screens of 33 patients were reviewed; 20 patients had abnormal studies. The thermoregulatory sweat tests of 19 patients were reviewed; 11 patients had abnormal studies. Composite Autonomic Severity Score was calculated for 33 patients and found abnormal in 20/33 patients (60.6%): 15/20 patients (75%) had mild impairment, and 5/20 patients (25%) had moderate impairment. The frequencies of testing abnormalities were: sudomotor 18/20 (90%), cardiovagal 9/20 (45%), and adrenergic 6/20 (30%). Sweat loss pattern analysis showed global, regional, and mixed patterns to be more common than length-dependent and distal patterns.

CONCLUSION

We found evidence of frequent autonomic dysfunction in primary lateral sclerosis, which is generally of modest severity akin to prior reports for amyotrophic lateral sclerosis, but more commonly in a pattern consistent with preganglionic/ganglionic localization. This suggests that primary lateral sclerosis, as with amyotrophic lateral sclerosis, is a multisystem disease that affects the autonomic nervous system.

Primary Lateral Sclerosis: An Overview

Primary lateral sclerosis (PLS) is a rare neurodegenerative disorder which causes the selective deterioration of the upper motor neurons (UMNs), sparing the lower motor neuron (LMN) system. The clinical course is defined by a progressive motor disability due to muscle spasticity which typically involves lower extremities and bulbar muscles. Although classically considered a sporadic disease, some familiar cases and possible causative genes have been reported. Despite it having been recognized as a rare but distinct entity, whether it actually represents an extreme end of the motor neuron diseases continuum is still an open issue. The main knowledge gap is the lack of specific biomarkers to improve the clinical diagnostic accuracy. Indeed, the diagnostic imprecision, together with some uncertainty about overlap with UMN-predominant ALS and Hereditary Spastic Paraplegia (HSP), has become an obstacle to the development of specific therapeutic trials. In this study, we provided a comprehensive analysis of the existing literature, including neuropathological, clinical, neuroimaging, and neurophysiological features of the disease, and highlighting the controversies still unsolved in the differential diagnoses and the current diagnostic criteria. We also discussed the current knowledge gaps still present in both diagnostic and therapeutic fields when approaching this rare condition.

Primary lateral sclerosis natural history study - planning, designing, and early enrollment

Introduction/Aims. Primary lateral sclerosis (PLS) is exceedingly rare and has been an enigmatic disease. Recent progress has drastically changed this perception, with early biomarkers being investigated and potential medications for PLS emerging at the preclinical stage. The aim of this paper is to describe a study of PLS natural history and discuss the limitations and proposed solutions to the study of a rare and slowly progressive disease. Methods. The PLS Natural History Study is a 30-site, 24-month, prospective study that is supported by multiple funding sources. The study aims to enroll 50 early PLS (disease duration ≤4 years) and 50 definite PLS (disease duration 4 to 15 years) participants using modified PLS Diagnostic Criteria. Smartphone-based assessments including semi-quantitative and quantitative measures and patient-reported outcomes are utilized. In-person quantitative measures are also completed during site visits. The change in the PLS Functional Rating Scale score is the primary outcome. The study utilizes the NeuroBANK^® patient-centric data capture and management platform. The biostatistical analysis plan has been developed. Results. In one year, 28 participants have been recruited. Enrollment has been much slower than anticipated due to the COVID-19 pandemic, the rarity of PLS, and potential study competition for internal resources from ALS clinical trials. Discussion. We discuss the need for more innovative methods to enroll and study individuals with such rare diseases and propose a number of mechanisms by which more efficient enrollment could be facilitated.

Prevalence of Sialorrhea Among Amyotrophic Lateral Sclerosis Patients: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative motor neuron disease (MND), and sialorrhea is a known symptom in patients with ALS, which may cause a social embarrassment and discomfort. However, people do not pay attention to sialorrhea up to now. This study is aimed at conducting a systematic review and meta-analysis of the pooled prevalence of sialorrhea in ALS patients all around the world and raising awareness of salivation.

METHODS

We searched PubMed and EMBASE databases to obtain the comprehensive literatures which reported the prevalence of sialorrhea. We used AHRQ and NOS to evaluate the literature quality. Subgroup analyses were performed based on screening instruments and severity of sialorrhea. At the meantime, sensitivity analyses was also conducted to identify the source of heterogeneity.

RESULTS

A total of 17 eligible studies which included 21 groups of data reported prevalence of sialorrhea. The pooled prevalence of sialorrhea among ALS patients was 30.8% (95% CI: 20.0%-44.2%). For studies using ALSFRS-R, direct questioning, postal survey, and ALSSoL average and ALSFRS-R, the pooled prevalence of sialorrhea was 22.7%, 25.8%, 29.8% and 52.0% respectively. According to the severity of sialorrhea, the prevalence of mild, moderate, and severe sialorrhea were 25.1%, 11.2%, and 10.5%, respectively. And none of the studies alone had a significant effect on the overall prevalence of sialorrhea after we eliminated each study separately in sensitivity analyses.

CONCLUSIONS

Sialorrhea is a relatively common symptom in ALS patients with a comparatively high prevalence. In our study, we found that the prevalence of sialorrhea in ALS patients is relatively higher than the results based on direct questioning or postal survey. Therefore, we deduced that sialorrhea should be evaluated by more complex professional assessment scales to improve the quality of life and improve early prognosis of disease.

Does limited EMG denervation in early primary lateral sclerosis predict amyotrophic lateral sclerosis?

Objective: We assessed whether a cohort of patients with primary lateral sclerosis (PLS) and limited electromyography (EMG) motor unit denervation changes evolve into amyotrophic lateral sclerosis (ALS) with prolonged follow-up. Methods: We initially ascertained all PLS patients diagnosed at Mayo Clinic-Rochester (1990-2016). Of 64 total cases, 43 had normal EMGs ("pure" PLS) during the first 4 years after symptom onset and were the focus of a prior publication, documenting absence of evolution to ALS. The remaining 21 patients had limited motor unit changes on EMG needle examination (denervation and most with fibrillation or fasciculation potentials) but insufficient to raise a strong suspicion of ALS; these 21 patients were followed to determine whether they evolved into ALS. Results: Of these 21 patients, the median follow-up was 7 years' disease duration (range: 4-27 years; IQR 5-8.5). They included 11 females (52%) with median onset-age of 57 years (range: 42-72 years). Two patients (10%) subsequently met revised El Escorial criteria for ALS after 7 and 13 years, respectively. The remainder had stable EMG changes with a persistent PLS phenotype. Among these remaining 19 patients, the PLS course was somewhat more aggressive than our previously reported series of 43 patients devoid of EMG denervation. The paraparetic variant was more common than the hemiparetic and bulbar variants, similar to "pure" PLS. Conclusions: Among PLS patients with definite but limited EMG denervation, 2/21 (10%) later developed ALS. The patients in this series had a more progressive clinical course compared to our previously reported pure PLS cases.

Natural History of "Pure" Primary Lateral Sclerosis

OBJECTIVE

To assess whether primary lateral sclerosis (PLS), classified as pure when the EMG is normal, converts to amyotrophic lateral sclerosis (ALS) after longitudinal follow-up.

METHODS

Retrospective chart review was performed of patients with pure PLS at Mayo Clinic in Rochester, MN (1990-2016). Inclusion criteria required a normal EMG during the first 4 years of symptoms.

RESULTS

Forty-three patients had pure PLS (25 female, 58%) with a median onset age of 50 years (range 38-78 years) and median follow-up at 9 years' disease duration (range 4-36 years). The ascending paraparesis phenotype (n = 30, 70%) was most common, followed by hemiparetic onset (n = 9, 21%) and bulbar onset (n = 4, 9%). Among the 30 paraparetic-onset cases, bladder symptoms (n = 18, 60%) and dysarthria (n = 15, 50%) were more common than pseudobulbar affect (n = 9, 30%) and dysphagia (n = 8, 27%). By the last follow-up, 17 of 30 (56%) used a cane and 6 (20%) required a wheelchair. The paraparetic variant, compared with hemiparetic and bulbar onset, had the youngest onset (48 vs 56 vs 60 years, respectively; p = 0.02). Five patients died; 1 patient required a feeding tube; and none required permanent noninvasive ventilation. Two patients developed an idiopathic multisystem neurodegenerative disorder, which surfaced after 19 and 20 years. Two patients developed minor EMG abnormalities. The remainder 39 had persistently normal EMGs.

CONCLUSIONS

Pure PLS did not convert to ALS after a median of 9 years' disease duration follow-up in our study population. The ascending paraparetic phenotype was most common, with earlier onset and frequent bladder involvement. After years of pure PLS, <5% develop a more pervasive neurodegenerative disorder.