How Sanfilippo and Like Disorders Affect 5 Senses Lacks Research, Experts Say

Problems with one or more senses are common in people with Sanfilippo syndrome and other mucopolysaccharidoses (MPSs), but there is very little research into how these impairments affect daily living or life quality, a new paper indicates.

Collecting data using questionnaires or forms filled in by patients that specifically report on sensory impairment, and assess quality of life, may help fill this gap.

The paper, “Assessing the impact of the five senses on quality of life in mucopolysaccharidoses,” was published in the Orphanet Journal of Rare Diseases.

MPSs are a family of disorders caused by problems in the enzymes that the body uses to break down glycosaminoglycans (GAGs), a type of complex sugar molecule. In these disorders, GAGs buildup, causing toxicity within cells and in different tissues. The exact effects vary among the different subtypes of MPS; Sanfilippo syndrome is also known as MPS type 3.

Each of the senses can be affected to varying degrees in different MPSs. However, the extent to which this impacts daily living or quality of life has not been a focus of research.

The “MPS & the five senses” meeting brought together 46 experts in MPS symptoms or the senses, as well as four people with these disorders. The aim of the meeting, held in Lisbon in May 2018, was to discuss how sensory loss could affect life for people with MPSs. It also aimed to determine best practices for assessing and managing sense-related symptoms.

Discussion focused on the traditional five senses: sight, hearing, speech, smell and taste, and touch.

Hearing problems are common across all MPSs, and these can lead to difficulties in communicating and engaging socially. Vision problems have also been reported across all MPSs, and they can hinder independence, mobility, and social engagement.

Nerve problems can result in decreased sensation or problems with the extremities, which can limit self-care and participation in activities. Smell and taste problems may also develop in people with MPSs, either due to the underlying diseases or as a result of other complications (e.g., frequent respiratory infections can alter both smell and taste).

Although the meeting was able to clearly identify these potential problems, research was lacking that could be used to understand their effects.

“Although it is clear that MPS can have a considerable negative impact on each of the five senses, it remains unclear how patients perceive these impairments and how these affect their overall [quality of life],” the researchers wrote.

Both physical tests and patient-reported outcome data could help to assess these symptoms in people with MPSs. However, patient-reported data is often not collected as part of MPS care.

“It is important to make a distinction between health and how patients perceive their health, which depends on how patients are coping with their impairments,” the experts wrote.

They suggested that incorporating patient-reported measures could allow for both better care and better data collection, and they provided an overview of tools currently available for this purpose.

These include the Spatial Hearing Questionnaire (for hearing), the Voice Outcome Survey (for speech), the Visual Function Short Form (for vision), the Health Assessment Questionnaire (for touch), the Brief Pain Inventory Short Form (for pain), and the Chronic Sinusitis Survey (for smell and taste).

Additionally, they recommended the five-level EuroQol five-dimensional questionnaire (EQ-5D-5 L) as a general tool for measuring quality of life among people with MPS.

Overall, this paper highlights gaps in current knowledge about how the senses are affected by MPS, and how people living with these conditions are in turn affected, suggesting avenues for research.

“Further research, i.e. collection of data in a standardized fashion using sense-specific [patient-reported outcome tools] and a general QoL [quality of life] tool such as the EQ-5D-5 L, is warranted and may provide a better insight in how and to what extent impairments in the senses affect [daily living] and the patients’ overall [quality of life],” the researchers concluded.