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Author's personal copy Journal of the Neurological Sciences 314 (2012) 83–87
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Gait pattern in myotonic dystrophy (Steinert disease): A kinematic, kinetic and EMG evaluation using 3D gait analysis Manuela Galli a, b, Veronica Cimolin a, c,⁎, Veronica Crugnola c, Lorenzo Priano c, d, Francesco Menegoni c, Claudio Trotti c, Eva Milano c, Alessandro Mauro c, d a
Bioengineering Department, Politecnico di Milano, Milan, Italy IRCCS “San Raffaele Pisana”, Tosinvest Sanità, Roma, Italy Department of Neurology and NeuroRehabilitation, Ospedale San Giuseppe, Istituto Auxologico Italiano, IRCCS, Piancavallo (Verbania), Italy d Department of Neurosciences, University of Turin, Italy b c
a r t i c l e
i n f o
Article history: Received 25 May 2011 Received in revised form 14 October 2011 Accepted 24 October 2011 Available online 25 November 2011 Keywords: Myotonic dystrophy Gait analysis Kinematics Kinetics EMG
a b s t r a c t We investigated the gait pattern of 10 patients with myotonic dystrophy (Steinert disease; 4 females, 6 males; age: 41.5 + 7.6 years), compared to 20 healthy controls, through manual muscle test and gait analysis, in terms of kinematic, kinetic and EMG data. In most of patients (80%) distal muscle groups were weaker than proximal ones. Weakness at lower limbs was in general moderate to severe and MRC values evidenced a significant correlation between tibialis anterior and gastrocnemius medialis (R = 0.91). An overall observation of gait pattern in patients when compared to controls showed that most spatio-temporal parameters (velocity, step length and cadence) were significantly different. As concerns kinematics, patients' pelvic tilt was globally in a higher position than control group, with reduced hip extension ability in stance phase and limited range of motion; 60% of the limbs revealed knee hyperextension during midstance and ankle joints showed a quite physiological position at initial contact and higher dorsiflexion during stance phase if compared to healthy individuals. Kinetic plots evidenced higher hip power during loading response and lower ankle power generation in terminal stance. The main EMG abnormalities were seen in tibialis anterior and gastrocnemius medialis muscles. In this study gait analysis gives objective and quantitative information about the gait pattern and the deviations due to the muscular situation of these patients; these results are important from a clinical point of view and suggest that rehabilitation programs for them should take these findings into account. © 2011 Elsevier B.V. All rights reserved.
1. Introduction Myotonic dystrophies are a group of autosomal-dominant multisystemic disorders with highly variable phenotypes [1]. Myotonic dystrophy type 1 (Steinert; DM1; OMIM 160900) is the most frequent of the adult-onset muscular dystrophies; its prevalence is estimated at 1/20 000 inhabitants. It is an autosomal-dominant disease characterized by a variety of multisystemic features and variable expression [2,3]. DM1 disease is caused by trinucleotide expansion of CTG in the myotonic dystrophy protein kinase gene, this mutation being dynamic and located in non-coding part of the gene. It is supposed that variability of DM1 is caused by a molecular mechanism due to mutated RNA toxicity. The number of CTG repeats in leucocytes varies from 50 to 80 in minimal DM, to 100–1000 in classic DM, and to even more than one thousand in congenital DM [4–6]. A significant inverse correlation is noted between age of onset and number of repeats, and there ⁎ Corresponding author at: Department of Bioengineering, Politecnico di Milano, Piazza L. Da Vinci 32, 20133, Milan, Italy. E-mail address:
[email protected] (V. Cimolin). 0022-510X/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.jns.2011.10.026
is a general correlation between the degree of expansion and the severity of clinical manifestations [7]. DM 1 is characterized by myotonia of the skeletal muscle myotonia, progressive myopathy, cataracts, cardiac conduction defects, gonadal dysfunction and neuropsychological impairment [8]. Specific clinical features are highly characteristic muscle involvement with early bifacial weakness, bilateral mild ptosis, neck flexion weakness and pronounced distal weakness of finger flexors as well as ankle dorsiflexors with foot drop. As the disease progresses, the myotonia becomes accompanied by distal more proximal muscle weakness, more pronounced in the upper than in the lower extremities [9–11]. Gait and balance disorders are two main functional consequences of the impairments linked to this pathology and patients have a significantly increased risk for stumbles and falls when compared to normal population [12]. They tend to progressively worsen as the clinical picture advances, which severely limits their quality of life. Even though movement difficulties, such as limited walking perimeter and gait speed, are frequently reported in daily clinical practice, they have not been thoroughly addressed in the scientific scenario, and their therapeutic approach remains poorly defined. To our knowledge, few
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quantitative studies assessed gait strategy in adult with DM1: they were conducted with not homogeneous sample sizes, using different techniques and markers configurations. Wright et al. [10] objectively analyzed the gait pattern of a group of 5 subjects affected by DM1 using infrared-emitting diodes affixed so as to bracket the hips, knees and ankles. They found an abnormal motion pattern at both hip and ankle, despite there being no evidence of proximal muscle weakness, such as hip muscles. In particular, they found prolonged and increased ankle plantar-flexion motion after heel strike as “foot slap” pattern. They concluded that myotonic gait pattern seems to be altered by distal muscle weakness (tibialis anterior and triceps surae), but it is probably not affected by myotonia or proximal weakness. Izco et al. [13] evaluated gait and upper extremity movement in a group of 40 MD subjects using spatio-temporal and kinematic variables. The gait pattern abnormalities were found at the knee and ankle joints and this finding was explained in terms of triceps surae and tibialis anterior weakness. In addition, rectus femoris' weakness was the culprit for the absence of flexion at knee in the initial gait cycle; no abnormalities were found at hip and pelvis, which paralleled the absence of proximal muscle weakness. Wiles et al. [12] investigated falls and risk factors in patients with DM1 using clinical assessments, lower limb muscle strength and spatio-temporal parameters during gait. Recently, Missaoui et al. [11] evaluated the significant improvement in patients' balance capacities after a rehabilitation program focused on strength, gait and balance in 20 patients with DM1. The definition and quantification of gait pattern in DM1 would contribute to a better understanding of the functional limitations related to this pathology and therefore, to an enhancement and optimisation of both physiotherapy and exercise prescription. The goal of this study was to evaluate quantitatively the impairments of a group of adults with DM1 compared to healthy age matched controls in terms of gait strategy using three-dimensional multifactorial gait analysis (GA) (spatio-temporal, kinematics, kinetics and EMG signal) based on an international and standardized protocol. Finally, using these data, our aim is to assess an adequate multidisciplinary rehabilitation for DM1 patients. 2. Materials and methods 2.1. Participants Ten adults subjects (4 females, 6 males; age: 41.5 ± 7.6 years) affected by DM1 were involved in this study; the diagnosis of
myotonic dystrophy was established by genetic analysis and validated by the Neurological team of the Institute. All patients had electrophysiological evidence of myotonia in both hand and leg muscles. Demographic and clinical characteristics are showed in Table 1. 20 adult subjects, age and sex matched, were recruited as healthy controls (Control group; CG; 10 females, 10 males; mean age: 37.23± 8.91 years). Selection criteria for the control group included no prior history of cardiovascular, neurological or musculoskeletal disorders. They showed normal flexibility and muscle strength and no gait abnormalities. The study was approved by the Ethics Research Committee of the Institute and the patients underwent the study after signing an informed consent according to the Italian law. 2.2. Experimental set-up The complete evaluation consisted of manual muscle test and 3D gait analysis (GA). Manual muscle test was performed according to the Medical Research Council Scale (MRC scale) [14], by an expert physical therapist; in particular the rectus femoris (RF), tibialis anterior (TA), and gastrocnemius (GEM) bilaterally were assessed bilaterally. All patients were evaluated at the Movement Analysis Laboratory of the “San Giuseppe” Hospital, Istituto Auxologico Italiano, Scientific Institute of Care and Research using an optoelectronic system with 6 cameras (460 VICON, Oxford Metrics Ltd., Oxford, UK) with a sampling rate of 100 Hz, two force platforms (Kistler, CH), 16-channel electromyography (EMG) system (STEP-PC, DEM, IT) working with a sampling frequency of 2000 Hz, and a video system. Markers (24 spherical passive retroreflective markers: 14 mm in diameter) were positioned according to Davis marker set [15]. For the surface EMG recording, bipolar Ag/AgCl surface electrodes pairs with a diameter of 10 mm and an inter-electrode spacing of 22 mm were placed bilaterally on clean, shaven skin overlying the rectus femoris (RF), semitendonosus (BFCL), tibialis anterior (TA) and gastrocnemius medialis (GEM) muscles. The SENIAM [16] recommendations for surface EMG were followed for electrode placement. The ground electrode was placed overlying the tibial tuberosity. EMG signals were pre-amplified, band-pass filtered (10–700 Hz) at a sampling rate of 2520 Hz, but not processed further. After one minute walking in the laboratory in order to gain familiarity with the environment, subjects were asked to walk barefoot at their own natural pace (self-selected and comfortable speed) along a (8 m long) walkway where the two force platforms were placed. At least six trials
Table 1 Clinical and demographic features of DM1 subjects (DM1: myotonic dystrophy). Pt #
Gender
Age [years]
Age at disease's start [years]
P1 P2
M F
44 40
41 10
P3a
M
41
P4 P5
F M
P6
CTG repeats
MRC GEM
MRC TA
MRC RF
ENG
Clinical signs
172 171
3.5 3.5
3.5 3.5
4 4
20
178
2
2
3
Normal Lower limbs' axonal neuropathy Axonal neuropathy
62 41
56 25
151 165
5 3
5 3
5 4
F
38
22
149
2
3
3
P7
M
39
12
185
2
1
3.5
Myotonia, ptosis, feet-drop Myotonia at 10; then ptosis, feet-drop, distal hypotrophy and weakness of lower limbs Walking difficulties, hand weakness, ptosis, lid lag, distal hypotrophy and weakness of lower limbs Myotonia, distal hypotrophy and weakness of upper limbs Feet-drop, myotonia, hypotrophy and weakness of upper and lower limbs Walking difficulties, myotonia, ptosis, distal hypotrophy and weakness of lower limbs Ptosis, dysphagia, hypotrophy and weakness of upper limbs
P8 P9 P10b
F M M
36 36 38
18 28 7
159 150 1000
2 5 3
3 4.5 3
4 5 3
Normal Lower limbs' axonal neuropathy Normal Lower limbs' axonal neuropathy Normal Normal Lower limbs' axonal neuropathy
Walking difficulties, facial weakness Mild weakness of distal lower limbs Walking difficulties, ptosis, feet-drop, facial weakness, frequent falls
Abbreviations: Pt #: patient identifier; Gender: male (M), female (F); MRC: Medical Research Council Score mean between left and right muscle (GEM: gastrocnemius medialis; TA: tibialis anterior; RF: rectus femoris); ENG: electroneurography. a P3 had a pharmacological treatment with vitamin E/selenium. b P10 had a pharmacological treatment with mexitil/creatina.
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were collected for each subject in order to ensure the consistency of the data. All the acquisitions were acquired by the same operator with experience, so to assure reproducibility of the acquisition technique and to avoid the introduction of errors due to different operators. 2.3. Data analysis All graphs obtained from GA were normalized as % of gait cycle and kinetic data were normalized for individual body weight. Using specific software (Smartanalyser, BTS, Italy) data were exported in .txt and .xls files. From these data format we identified and calculated some indices (time/distance parameters, angles joint values in specific gait cycle instant, peak values in joint power graphs) in order to quantify the gait pattern of participants involved in this study. This procedure was performed by the same operator to ensure data reproducibility. The following parameters were evaluated: Spatio-temporal parameters: - % stance: duration of the stance phase (as % of the gait cycle); - velocity: mean velocity of progression (m/s); - step length: longitudinal distance from one foot strike to the next one, normalized to subject's height; - cadence: number of steps in a time unit (steps/min); - step width (m). Kinematics: - the mean value of pelvic tilt (Mean PT index), expressed in degrees; - the values of angle of ankle (AIC index), knee (KIC index) and hip joint (HIC index) at the contact of the foot with the ground (i.e. Initial Contact or IC), expressed in degrees; - the values of maximal ankle dorsiflexion during stance phase (AMSt index) and the maximal flexion of the knee (KMSw index) and ankle (AMSw index) joint during swing phase, expressed in degrees; - the values of minimal ankle dorsiflexion in stance phase (AmSt index), knee (KmSt index), and hip flexion (HmSt index) during the gait cycle, expressed in degrees; - the range of motion of the pelvic tilt (PT-ROM index) and the hip joint on sagittal (H-ROM index) plane; the range of motion of knee (K-ROM index) on sagittal plane; the range of motion of ankle on sagittal plane during stance phase (A-ROM index), expressed in degrees. Kinetics: Hip power: - the maximum value of generated hip power during loading response (maximum value of positive hip power during loading response). Knee power: - the maximum value of generated knee power during loading response (maximum value of positive knee power during loading response). Ankle power: - the maximum value of absorbed power during loading response and mid-stance (maximum value of negative ankle power during loading response and midstance) (APmin) representing the ability to absorb the impact of the foot to the ground; - the maximum ankle power during terminal stance (maximum value of positive ankle power; APMax index), expressed in W/Kg; this parameter represents the push-off capacity during walking and is related to the forward propulsive power during gait. EMG: As concerns EMG data, abnormalities of EMG timing were qualitatively required for the definition of abnormal muscle activity. The
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criteria were derived from our database on normal subjects and from literature [17,18] and were as follows: a) Plantarflexor activity in terminal swing continuing until foot contact or at latest at initial contact, with prolonged activity in stance; b) Knee extensor activity in mid or late stance; c) Hamstring activity reaching or exceeding midstance; d) Continuous knee extensor activity during swing phase.
2.4. Statistical analysis All the previously defined parameters were computed bilaterally for each participant and the mean and standard deviation values of all indexes were calculated for each group (DM1 group and CG). Kolomogorov–Smirnov tests were used to verify if the parameters were normally distributed; the parameters were not normally distributed, so we used Wilcoxon signed rank test for comparing data of the right and the left side and the Mann–Whitney U-test for comparing DM1 group and CG. A statistically significant difference was accepted as p b 0.05. The Spearman correlation coefficient (rho) was calculated to examine the relationship between different measures. 3. Results 3.1. Manual muscle test Functionally all patients exhibited bilateral weakness of the upper and lower limbs and were able to walk unaided for at least 200 m without any support device. The MRC mean between left and right muscle scores was reported for each muscle in Table 1. As concerns lower limbs, data showed mainly distal weakness: in 8 out of 10 patients distal muscle groups were weaker than proximal muscles, one patient showed ubiquitous lower limb weakness and one patient showed normal strength. Strength deficits were symmetrical. In most patients (80%), lower limb weakness was moderate to severe: in 6 patients, the most tested muscle groups had MRC scores of grade 3 or lower. Even more, MRC values highly correlated (R > 0.77, p b 0.05), most significantly between tibialis anterior and gastrocnemius medialis (R = 0.91, p b 0.05). No correlation was found between muscular weakness and duration of the disease. Five out of 10 patients presented electrophysiological signs of axonal polyneuropathy, but no correlations were found between presence of polyneuropathy and weakness. 3.2. Gait analysis For gait parameters an initial comparison between right and left lower limb was made. As no statistical difference was found between the two limbs, the data from both sides were pooled. In Table 2 the mean values (standard deviation) of spatiotemporal parameters, kinematic and kinetic indices considered in this study for DM1 and CG are reported. All spatio-temporal parameters in DM1 group were significantly different from CG: velocity, step length and cadence were significantly lower in DM1 compared to healthy controls. Duration of stance phase (% stance) and step width values were higher than CG even if a statistical difference was not evidenced. In terms of kinematic parameters, the pelvic tilt displayed a higher mean value (Mean PT index) than control group with a range of motion (PT-ROM index) close to physiological values. The hip was close to normality at initial contact (HIC index), but a limited extension ability at the end of stance phase (HmSt index) was
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Table 2 Spatio-temporal, kinematic and kinetic parameters (mean and standard deviation) for the two analyzed groups (DM1 and CG; DM1: myotonic dystrophy; CG: control group). DM1 Spatio-temporal parameters Velocity (m/s) Step Length (m) Cadence (steps/min) Step width (m) % stance (%gait cycle)
0.75 0.88 101.44 0.19 64.70
CG (0.18)⁎ (0.15)⁎ (11.65)⁎ (0.04)⁎ (3.30)
1.30 1.33 117.98 0.13 60.10
(0.10) (0.08) (3.84) (0.02) (1.33)
Pelvic tilt (°) Mean PT PT-ROM
15.10 (4.56)⁎ 3.82 (5.21)
8.84 (4.57) 1.2 (2.9)
Hip flex-extension (°) HIC HmSt H-ROM
35.42 (7.28) 4.21 (9.52)⁎ 32.73 (9.21)⁎
34.12 (4.04) − 10.50 (4.37) 44.85 (4.76)
Knee flex-extension (°) KIC KmSt KMSw K-ROM
5.88 0.63 67.17 67.20
(6.60) (8.55) (8.62)⁎ (8.23)⁎
− 1.91 21.29 − 8.56 31.11 4.42
(3.32) (12.95)⁎ (6.65)⁎ (5.68) (5.05)
Ankle dorsi-plantarflexion (°) AIC AMSt AmSt A-ROM AMSw
of the positive area during terminal stance (APMax index), representative of the push off ability, was significantly lower than CG mean value; normalizing to the velocity of progression the differences remained unchanged. EMG activity showed that while RF presented no significant abnormalities, the BFCL showed a delaying and abnormal activation during midstance. TA presented a prolonged activation after 10% of gait cycle and physiological features in swing phase; GEM displayed delayed activity during stance phase and activation also during swing phase, showing a co-contraction with TA in swing phase (Fig. 1). No significant correlations were found between GA parameters and demographic and clinical features (BMI, age, and gender, disease duration, muscular weakness, polyneuropathy). A slight correlation was found only between weakness of rectus femoris and reduced walking speed (R = 0.62, p b 0.05). 4. Discussion
4.06 0.12 60.15 60.06
(6.63) (3.82) (3.53) (3.76)
− 0.53 12.95 − 18.52 31.47 3.81
(2.66) (2.44) (6.10) (4.98) (2.09)
Hip power (W/Kg) HPMax
1.34 (0.77)⁎
0.62 (0.51)
Knee power (W/Kg) KPMax
0.98 (0.99)
0.69 (0.59)
Ankle power (W/Kg) APmin APMax
− 0.92 (0.35) 1.81 (1.24)⁎
− 1.04 (0.25) 3.56 (0.66)
Abbreviations: ROM: range of motion; PT: pelvic tilt; H: hip joint; HIC: hip at IC; HmSt: hip minimum in stance; K: knee joint; KIC: knee at IC; KmSt: knee minimum in stance; KMSw: knee maximum in swing; A: ankle joint; AIC: ankle at IC; AMSt: ankle maximum in stance; AmSt: ankle minimum in stance; AMSw: ankle max in swing; HPMax: hip power maximum; KPMax: knee power maximum; APmin: ankle power minimum; APMax: ankle power maximum; IC: initial contact. ⁎ p b 0.05, DM1 versus CG.
observed in comparison with healthy controls. Range of motion at hip joint (H-ROM index) was reduced. As concerns knee flex-extension plot, pathological group revealed physiological values during loading response (0%–10% of gait cycle; HIC index) and midstance (10%–30% of gait cycle; KmSt index). In particular, it is important to note that in DM1 patients a significant percentage of individuals revealed tendency to knee hyperextension during midstance (12/20 limbs: 60% of limbs). Deviations at the knee were also present during the swing phase: patients achieved higher values of knee flexion (KMSw index) conducing to larger excursion of knee joint (K-ROM index) than CG. Feet were in a quite physiological position at initial contact (AIC index) and the ankles presented higher dorsiflexion during stance phase (AMSt and AmSt indices) if compared to CG; ankle joint excursion during stance phase was close to normality; no limitations in ankle dorsiflexion ability in swing phase were assessed. Sagittal plane kinetics evaluation showed higher hip power (HPMax index) during loading response and no statistically different knee power (KPMax index). The analysis of ankle power plot revealed that the peak of negative ankle power area after initial contact (APmin index), which is representative of the absorption power during the impact on the ground, was close to normality. Conversely, the maximum
The aim of this study was the objective and quantitative evaluation of gait pattern of 10 DM1 subjects; indeed, only few previous studies have assessed this item so far. Manual muscular test demonstrated that MRC scores in distal muscles were equal to lower than those in proximal muscles in all patients, confirming that the progressive muscular weakness is more distal than proximal [10]. The stronger correlation found between MRC scores of tibialis anterior and of gastrocnemius, suggests that distal weakness affect both muscles and is partially in relation with weakness of rectus femoris. The potential correlation found between BMI and MRC scores of gastrocnemius medialis and tibialis anterior, needs to be verified with more subjects, nevertheless it could be taken as an hint to therapist in order to improve the treatment of these patients. In 5 patients we found an axonal polineuropathy not related to any metabolic, toxic or genetic disorder. This finding has already reported in literature; some authors deny the presence of polyneuropathy [19,20] while others suggest a strong correlation between muscular weakness and polyneuropathy [21]. An overall observation of gait pattern in DM1 patients confirmed previously reported data as concerns spatio-temporal parameters and kinematics. Spatio-temporal gait parameters of this group showed that the combination of short stride length and slow cadence results in a significantly reduced walking speed. Furthermore the slow velocity is associated with an increased step width and increased stance phase.
Fig. 1. EMG plots of TA (tibialis anterior) and GEM (gastrocnemius medialis) of a patient during the gait cycle. The plots are normalized to the gait cycle (0% and 100% correspond to two consecutive initial contacts f the same limb; vertical bar represents the toe-off). Gray bars on the bottom of each graph represent the normal activation timing during the gait cycle.
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These data demonstrate that the DM1 subjects are unstable during walking also at self selected speed probably due to the weakness of lower extremity, and maybe enhanced by the difficulty to maintain stability and up-right posture during gait. In terms of kinematics, pelvic tilt revealed an anterior position and the hip joint was generally characterized by limited extension ability during midstance and reduced hip excursion during the gait cycle [2]. The knee pattern revealed the presence of hyperextension during midstance in a large percentage of patients that is consistent with the presence of abnormal knee flexors activity in this phase of gait cycle. In swing phase higher and abnormal knee flexion ability was displayed leading to a wide knee movement excursion, as showed by knee range of motion; this pattern was not connected to the presence of a drop foot, as demonstrated by the AMSw parameter which was close to normality, and may represent a compensation mechanism in order to contrast the muscle weakness. As concerns ankle joint pattern, higher dorsiflexion ability in midstance was evident: this strategy may be directly connected to the TA prolonged activation after 10% of gait cycle and delayed activity of GEM. In addition plantarflexion motion was both limited and prolonged after heel-strike (“foot-slap” pattern), confirming literature [10]. This pattern may be due to the abnormal GEM activation during swing phase which contrasts the physiological TA action displayed by EMG signals. Sagittal plane kinetics evaluation showed that higher hip power generation in the first part of the stance phase (HPMax index) was present. It may be due to concentric contraction of the hip-extensor and secondary to the anterior pelvic tilt displayed by these patients. Peak power generated at ankle joint in the terminal stance (APMax index) was also analyzed. Limited muscle strength distally together with the low velocity during walking was probably the causes of the reduced value of this index. However the main contribution is due to the limited muscle strength as the same result was obtained normalizing the parameter to the velocity of progression. Our results support the hypothesis confirmed that there is no evidence that gait, also in more severely affected patients, is not altered by proximal muscle weakness, but by weakness of the TA and GEM. Thus, although a muscle disorder may not explain the abnormalities at proximal joint motion, the observed limitations may result from dysfunction of some portions of the central nervous system controlling gait [10] or from coping response. These results may be useful from a clinical point of view as 3D GA; in particular, quantitative data related to kinetics and especially to muscles activity provided information in order to give a clearer insight into the gait pattern in these patients. From a clinical perspective it is very important to evaluate the gait pattern in these patients using both clinical examination and instrumental quantitative measures, not only with regard to kinematics but also kinetic and EMG data of mainly lower limb joints. The assessment of gait pattern using only spatiotemporal parameters and kinematics is not enough because they give a limited evaluation of patient's walking ability; for this reason the integration of these data with kinetics and EMG is useful for better investigating the joint reactions, moments, powers and muscular activity. In this way it is possible to assess the mechanisms that either control or produce movement, thus potentially developing a more comprehensive understanding of motion and providing insight not only into the ‘how’ (kinematics), but also into the cause (kinetics) of the movement we observe. In addition, dynamic EMG provides the timing and action of muscles. When, in fact, EMG recordings are combined with kinematics, kinetics and the physical examination results, a comprehensive snapshot of the subject's walking pattern is revealed, providing an empirical basis for identifying the functional cause of a gait abnormality [18]. According to the quantitative data obtained by GA, in particular from EMG signal, we are able to identify the more compromised muscles (mainly distal muscles) and to establish a specific rehabilitative protocol to delay the progression of the disease in these muscles.
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The findings of this study support that, beyond a multidisciplinary therapeutic care for these patients, a meticulous evaluation patient's impairment, such as using GA for the quantification of gait disorders, should be conducted before proposing a rehabilitation protocol based on clearly defined and accepted objectives. A potential weakness of this study may be the small number of participants which resulted in limited strength of the statistical findings; further studies should be conducted in order to confirm our results with a larger population. However this study represents an attempt to deeply investigate the gait strategy in patient with DM1 and can help to establish a suitable rehabilitation protocol focused on balance, gait and muscle strength improvement, permitting extended/prolonged deambulation in these patients therefore permit the patients a better quality of life.
Conflict of interest statement All authors haven’t any conflicts of interest and any financial interest.
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