Poor Neck Proprioception May Cause Balance Deficits in Myotonic Dystrophy 1

Completed

• Conditions: Myotonic Dystrophy 1
• Interventions: Other: Pathologic group; Other: Healthy subjects

• Registration Number: NCT04712422
• Lead Sponsor: Istituto Auxologico Italiano

Brief Summary

Impairment of balance and gait are frequent complaints in patients with myotonic dystrophy type 1 (DM1). In these persons, there is an increased risk for stumbles and falls when compared to normal subjects. An underestimated cause of falls might be the weakness of neck flexor muscles (due to cervical ataxia). It is well known that fibres of muscle spindles are receptors combining a specialized sub-set of muscle fibers with a specialized array of both sensory and motor nerve fibers. Spindles transduce into neural afferent discharges the muscle length and length changes. They are very dense in deep neck muscles, are crucial to body balance and gage orientation, and are severely affected in DM1. Preliminary results suggest that falls could reflect imbalance. These indicate that cervical ataxia may come into play because of muscle spindle fibre disruption. In light of the current knowledge on the physiology of balance and on the association between balance deficits and cervical dystonia in other clinical conditions (e.g., whiplash injury), a rationale is therefore offered to a confirmation of the hypothesis that DM1 patients may suffer from cervical ataxia.

The primary endpoint is the demonstration of an association between balance deficits in standing and cervical proprioception deficit in adults affected by Myotonic dystrophy 1.

Secondary endpoints are:

* the investigation of the correlation among the two deficits and the clinical conditions of patients,

* the definition of normative data in the measure of cervical proprioception in a sample of healthy participants.

It is expected that high scores in postural balance, obtained on the posturographic Equitest™-Sensory Organization Test-SOT, correspond to high levels of repositioning accuracy in tests of cervical repositioning and low SOT scores correspond to low accuracy. Moreover, it is expected that an association exists among the two deficits and the clinical situation of the patients. Results from the present pilot study will allow an estimate of the sample size for future experimental protocols. The evidence for an association between balance deficits and cervical ataxia would be of obvious relevance to the patients. This would also support the hypothesis that neck muscle spindles may be especially affected in DM1. This would highlight that muscles are also crucial sensory organs, involved in the perception of joint position, muscle strength, and fatigue. Results from the present study might allow the definition of new rehabilitative programs, such as treatments through a neck strengthening (and thus stiffening) exercise program. This study, therefore, might stimulate new research hypothesis at the neurophysiologic level and possibly lead to findings generalizable from DM1 to other forms of myopathy.

Detailed Description

Not available

Study Timeline

• Study Start: 2020-10-27
• Study First Submitted: 2021-01-13
• Study First Submitted QC: 2021-01-13
• Study First Posted: 2021-01-15
• Primary Completion: 2021-10-13
• Study Completion: 2022-12-31
• Status Verified: 2024-02
• Last Update Submitted: 2024-02-16
• Last Update Posted: 2024-02-20

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 42

Inclusion Criteria

• Diagnosis of DM1 since at least 5 years;
• Ability to stand erect with open eyes for at least 20 s;
• Rivermead Mobility Index (RMI) score ≥ 10/15;
• Visual acuity > 10/20, also with corrective lenses;
• Mini Mental State Examination (MMSE) score ≥ 26/30;
• ability to wittingly sign the informed consent form.

Exclusion Criteria

• neurological or orthopedic pathologies with impact on balance;
• pregnancy;
• previous orthopedic surgical intervention;
• head or neck trauma in the 6 months preceding the study;
• other pathological conditions which could alter balance;
• drug therapy, underway for less than one month before the study, with impact on balance.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Pathologic group	Pathologic group	At least 22 participants with diagnosis of Myotonic Dystrophy 1.
Healthy participants	Healthy subjects	At least 25 healthy participants aged from 18 to 50 years old. Participants will be excluded if pregnant.

Primary Outcome Measures

Name	Time	Method
SOT score	Day 1	The patient's task is to maintain an upright stance during 3 20 s trials under six different conditions, including platform and visual surround 'tuned' with individual's sagittal oscillation. The SOT score will be calculated by comparing the sagittal oscillation of the body's centre of mass (COM) to the maximal sagittal oscillation. Score is averaged across the six conditions (range 0 - 100 the higher the score, the lower the oscillation).

Secondary Outcome Measures

Name	Time	Method
Head Repositioning Accuracy, HRA	Day 1	The head repositioning accuracy in percentage will be computed as the joint position error (JPE) divided by the target position. The JPE will be computed as the absolute difference between the target position and the measured position.

Trial Locations

Locations (2)

The NEuroMuscular Omnicentre (NEMO) Clinical Center; 🇮🇹 Milan, MI, Italy

Istituto Auxologico Italiano; 🇮🇹 Milan, MI, Italy