Mastication in Patients with Spinal Muscular Atrophy Types 2 and 3 is Characterized by Abnormal Efficiency, Reduced Endurance, and Fatigue

The test of masticating and swallowing solids (ToMaSS): An investigation of applicability and clinical utility in children with orofacial myofunctional disorders

BACKGROUND

Orofacial myofunctional disorders (OMD) are often associated with limitations of oral ingestion of solid food. The Test of Masticating and Swallowing Solids (ToMaSS) is a simple diagnostic tool to assess and quantify oropharyngeal efficiency while eating a standardised cracker.

OBJECTIVES

The objective of this study was to investigate the applicability and clinical utility of the ToMaSS in children with OMD.

METHODS

In this case-control study, data were collected from 18 children between 4 and 11 years with confirmed OMD. Inter-rater reliability and age effects on the ToMaSS parameters were investigated and the specific performance profile of the OMD children was identified.

RESULTS

Inter-rater reliability was excellent for the ToMaSS parameters 'bites' (ICC = .999), 'masticatory cycles' (ICC = .961), 'time'(ICC≧ .999) and good for 'number of swallows' (ICC = .810). 'Masticatory cycles' and 'time' decreased as a function of age with a significant difference in the 'number of masticatory cycles' between the youngest (4-6 years) and oldest (10-14 years) participants (p = .006, Z = -2.739). Deviations from normative data in at least one of the four ToMaSS parameters were found in 90% of the OMD children with 'bites', and 'masticatory cycles' predominantly corresponding to the performances expected in typically-developing children in younger age groups.

CONCLUSIONS

The ToMaSS is a reliable diagnostic instrument and clinically useful to detect limited efficiency of oral solid bolus intake and specific impairments in chewing function and duration of food intake in children with OMD. Our data suggest that OMD is associated with delayed development of efficient solid bolus preparation.

Exploring Texture and Biomechanics of Food Oral Processing in Fork-Mashable Dishes for Patients with Mastication or Swallowing Impairments

Texture-modified diets (TMDs) are a primary compensatory treatment for hospitalized older patients with swallowing and mastication disorders. Nevertheless, the lack of a protocol for evaluating their objective textural properties hampers their industrialization and optimal patient care.

OBJECTIVES

This study aimed (a) to evaluate the textural properties (maximum force, cohesiveness, and adhesiveness) and biomechanics of food oral processing (mastication cycles, time, and frequency) of ten fork-mashable dishes (Texture E BDA/IDDSI level 6), (b) to explore the impact of oral processing on texture, and (c) to measure the properties of the ready-to-swallow bolus (RSB) in healthy adults.

METHODS

The textural properties (maximum force, cohesiveness, and adhesiveness) of ten dishes were analyzed with a texture analyzer before and after oral processing (RSB) in five healthy adults (30 ± 3.9, 3 women). Surface electromyography was used to measure mastication cycles, time, and frequency.

RESULTS

The pre-mastication Texture Profile Analysis (TPA)-averaged values of maximum force ranged from 0.65 to 2.73 N, cohesiveness was 0.49-0.87, and adhesiveness was 0.01-0.95 N·s. Masticatory Cycles (46.87-19.13 MC) and time (36.73-15.80 S) from whole samples to RSB greatly and significantly differed among dishes, although frequency did not (1.68-1.11 MC/T). Post-mastication RSB TPA-averaged values of maximum force ranged from 0.70 to 2.24 N; cohesiveness, 0.49-0.73; and adhesiveness, 0.01-1.14 N·s.

CONCLUSIONS

Despite all dishes being classified by the same qualitative descriptor (BDA level E/IDDSI level 6), there was a large and significant variation in their textural properties (maximum force, cohesiveness, and adhesiveness) when measured in SI units. In addition, in healthy adults, the masticatory cycles and time to achieve RSB greatly differed, whereas masticatory frequency remained quite constant.

Assessing Prevalence and Characteristics of Oro-bulbar Involvement in Children and Adults with SMA Type 2 and 3 Using a Multimodal Approach

Bulbar and jaw muscles are impaired in patients with Spinal Muscular Atrophy (SMA) but the assessment of their severity and progression are limited by the lack of age-appropriate and disease-specific measures. We investigated mastication and swallowing in children and adults with SMA, sitters and walkers. In a 2-year multicentre cross-sectional prospective study, lip and tongue strength (Iowa Oral Performance Instrument), chewing and swallowing (Test of Masticating and Swallowing Solids), active mouth opening (aMMO) were compared to age-appropriate normative data. The perceived burden of oro-bulbar involvement (SMA-Health Index) was recorded. 78 patients were included, 45 children (median age 7.4 years),22 adults (median age 26.8 years) on nusinersen and 11 untreated (median age 32.7 years). Forty-three percent children had reduced mouth opening, 50% had prolonged total time to eat. These issues were more prominent in sitters than in walkers (p = 0.019, p = 0.014). Sixty-six percent needed increased swallows for bolus clearance. Nusinersen treated adults had median aMMO, tongue strength and total time at TOMASS values within normal range (z score: -1.40, -1.22, -1.32, respectively) whereas untreated adults had reduced aMMO (z score: -2.68) and tongue strength (z score: -2.20). Only a minority of children (2/17) and treated adults (5/21) reported burden in swallowing or mastication compared to all untreated adults (5/5). After 16 months, mastication and swallowing were stable in treated children and adults, whether sitters or walkers. The reported multimodal approach to assess oro-bulbar functions demonstrate that swallowing and mastication are impaired in SMA despite patients' perception. These results suggest a trend towards stabilization of oro-bulbar function in patients on long-term treatment with nusinersen.

Onasemnogene abeparvovec preserves bulbar function in infants with presymptomatic spinal muscular atrophy: a post-hoc analysis of the SPR1NT trial

Bulbar function in spinal muscular atrophy has been defined as the ability to meet nutritional needs by mouth while maintaining airway protection and communicate verbally. The effects of disease-modifying treatment on bulbar function are not clear. A multidisciplinary team conducted post-hoc analyses of phase 3 SPR1NT trial data to evaluate bulbar function of infants at risk for spinal muscular atrophy who received one-time gene replacement therapy (onasemnogene abeparvovec) before symptom onset. Three endpoints represented adequate bulbar function in SPR1NT: (1) absence of physiologic swallowing impairment, (2) full oral nutrition, and (3) absence of adverse events indicating pulmonary instability. Communication was not assessed in SPR1NT. We descriptively assessed numbers/percentages of children who achieved each endpoint and all three collectively. SPR1NT included infants <6 postnatal weeks with two (n = 14) or three (n = 15) copies of the survival motor neuron 2 gene. At study end (18 [two-copy cohort] or 24 [three-copy cohort] months of age), 100% (29/29) of patients swallowed normally, achieved full oral nutrition, maintained pulmonary stability, and achieved the composite endpoint. When administered to infants before clinical symptom onset, onasemnogene abeparvovec allowed children at risk for spinal muscular atrophy to achieve milestones within published normal ranges of development and preserve bulbar function.

Development of an International SMA Bulbar Assessment for Inter-professional Administration

BACKGROUND

Progressive weakness can affect bulbar muscles in individuals with moderate to severe forms of spinal muscular atrophy (SMA). The paucity of standardized, valid bulbar assessments capturing clinically significant deficits in SMA impedes the ability to monitor function, facilitate intervention, or detect treatment response.

OBJECTIVE

To fill this void, an international multidisciplinary team gathered to develop an agreed upon consensus-derived assessment of bulbar function in SMA for inter-professional administration to enhance our ability to monitor disease progression, support clinical management, and evaluate treatment effects.

METHODS

Fifty-six international clinicians experienced in SMA were invited and engaged using the Delphi method over multiple rounds of web-based surveys to establish consensus.

RESULTS

Serial virtual meetings occurred with 42 clinicians (21 speech and language therapists, 11 physical therapists, 5 neurologists, 4 occupational therapists, and 1 dentist). Seventy-two validated assessments of bulbar function were identified for potential relevance to individuals with SMA (32 accessible objective, 11 inaccessible objective, 29 patient-reported outcomes). Delphi survey rounds (n = 11, 15, 15) achieved consensus on individual items with relevance and wording discussed. Key aspects of bulbar function identified included: oral intake status, oral facial structure and motor strength, swallowing physiology, voice & speech, and fatigability.

CONCLUSIONS

Multidisciplinary clinicians with expertise in bulbar function and SMA used Delphi methodology to reach consensus on assessments/items considered relevant for SMA across all age groups. Future steps include piloting the new scale moving towards validation/reliability. This work supports the advancement of assessing bulbar function in children and adults with SMA by a variety of professionals.

Measuring Fatigue and Fatigability in Spinal Muscular Atrophy (SMA): Challenges and Opportunities

Fatigue, a common symptom, together with the characteristic of performance fatigability, are well-documented features of SMA that impact quality of life and function. Importantly, establishing associations between multidimensional self-reported fatigue scales and patient performance has proven difficult. This review was conducted to evaluate the various patient-reported fatigue scales applied in SMA, with the objective of considering the limitations and advantages of each measure. Variable use of fatigue-related nomenclature, including conflicting terminology interpretation, has affected assessment of physical fatigue attributes, specifically perceived fatigability. This review encourages the development of original patient-reported scales to enable perceived fatigability assessment, providing a potential complementary method of evaluating treatment response.

Objective measurement of oral function in adults with spinal muscular atrophy

BACKGROUND

Impairment of bulbar function in adult individuals with spinal muscular atrophy (SMA) usually is not assessed by established motor scores. Measurements of oral function including quantitative muscle and endurance tests are able to detect subtle changes. The aim of this study was to systematically evaluate the measurement of maximum bite force and endurance, maximum tongue pressure and endurance, as well as maximum mouth opening in adult individuals with SMA types 2 and 3.

METHODS

Data from oral function tests in 43 individuals were analyzed. Differences in oral function between individuals with different SMA types and numbers of SMN2 copies were tested. Spearman´s rho correlations among oral function measures themselves as well as with established clinical outcome scales were analyzed.

RESULTS

The absolute maximum measures of oral function (maximum bite force, maximum tongue pressure, maximum mouth opening) were able to discriminate between individuals with different SMA types, individuals with a different number of SMN2 copies and with different walking abilities. The pairwise correlations of the absolute maximum measures of oral function were fair to moderate in size; the same was true for their correlations with the established motor scores. All correlations assessing endurance measures of oral function were weaker and statistically insignificant.

CONCLUSIONS

Among the oral function tests maximum tongue pressure and maximum mouth opening are particulary promising as clinical and sensitive outcome measures for clinical trials. Oral function tests may supplement existing motor scores, in particular concerning specific questions about bulbar function or in severely affected non-ambulatory individuals where mild (treatment-related) changes would otherwise remain undetected. Trial registration DRKS, DRKS00015842. Registered 30 July 2019, https://drks.de/search/de/trial/DRKS00015842.

A Within-Subject Comparison of Face-to-Face and Telemedicine Screening Using the Timed Water Swallow Test (TWST) and the Test of Mastication and Swallowing of Solids (TOMASS)

The Timed Water Swallow Test (TWST) and the Test of Mastication of Solids (TOMASS) are dysphagia screening procedures that have been shown to be reliably assessed from video. The reliability of the procedures performed over telemedicine has not previously been assessed. TWST and TOMASS outcomes in two situations (both face-to-face and over telemedicine) were compared for 48 participants (aged 60-90; 27 with clinical conditions and 21 older persons). Both testing situation and test performed order were randomized, and all assessment procedures were performed within 3 h of each other. The results indicated a high level of agreement between face-to-face and telemedicine screening outcomes for TWST and TOMASS, respectively. The assessments indicated an 83% and 76% agreement in classifications of individual participants as within or outside normal limits for the TWST and TOMASS for the two test situations. The TWST showed a balanced distribution in differing classification in telemedicine (0.16-0.19 error rates). The TOMASS procedure classified more participants as outside normal limits over telemedicine compared to face-to-face administration. Agreement in the observed number of swallows was substantially lower than other outcome measures, which is attributed to increased difficulty in observing this property over video. Most participants (60%) reported that they would prefer telemedicine over face-to-face assessments, and 90% viewed the procedure as more accessible than expected. All participants were satisfied with the telemedicine procedures. The results suggest that clinical assessment of dysphagia over telemedicine using the TWST and TOMASS are viable alternatives to face-to-face administration of the procedures.

Patients with Spinal Muscular Atrophy Type 1 Achieve and Maintain Bulbar Function Following Onasemnogene Abeparvovec Treatment

BACKGROUND

Improvement and maintenance of bulbar function are goals of disease-modifying treatments for spinal muscular atrophy (SMA). Lack of standardized measures and a widely accepted definition of bulbar function represents a gap in SMA care.

OBJECTIVE

A multidisciplinary team conducted post-hoc analyses of pooled data from one phase 1 (START) and two phase 3 (STR1VE-US, STR1VE-EU) studies to define and evaluate bulbar function of infants with SMA type 1 after receiving one-time gene replacement therapy, onasemnogene abeparvovec.

METHODS

We defined bulbar function as the ability to meet nutritional needs while maintaining airway protection and the ability to communicate verbally. Four endpoints represented adequate bulbar function: (1) absence of clinician-identified physiologic swallowing impairment, (2) receiving full oral nutrition, (3) absence of adverse events indicating pulmonary instability, and (4) the ability to vocalize at least two different, distinct vowel sounds. We descriptively assessed numbers/percentages of patients who achieved each endpoint and all four collectively. Patients were followed until 18 months old (STR1VE-US and STR1VE-EU) or 24 months (START) post-infusion.

RESULTS

Overall, 65 patients were analyzed for swallowing, nutrition intake, and adverse events, and 20 were analyzed for communication. At study end, 92% (60/65) of patients had a normal swallow, 75% (49/65) achieved full oral nutrition, 92% (60/65) had no evidence of pulmonary instability, 95% (19/20) met the communication endpoint, and 75% (15/20) achieved all four bulbar function components in the composite endpoint.

CONCLUSIONS

In these three clinical trials, patients with SMA type 1 who received onasemnogene abeparvovec achieved and maintained the bulbar function criteria utilized within this investigation.