Participants and Demographic Data
Seventy subjects were enrolled in this study 55 females and 15 males; their mean age was (36.60 ± 9.24) years. Description of participants’ demographic characteristics are presented in (Table 1).
Table 1
Participants' Demographic Characteristics
Characteristic | MS (n = 70) |
Age (Years) (mean ± SD) | 36.60 ± 9.24 |
Handedness (mode) Right [n (%)] | 1.00 62 (88.6) |
Gender (mode) Female [n (%)] | 1.00 55 (78.6) |
MS Subtype RRMS [n (%)] SPMS [n (%)] PPMS [n (%)] | 65(92.9) 2 (2.9) 3 (4.3) |
Age at onset of symptoms (Years) (mean ± SD) | 26.11 ± 8.162 |
Disease Duration (Years) (mean ± SD) | 10.60 ± 7.198 |
BMI (Kg/m2) (mean) | 26.06 ± 5.49 |
Education (Years) (mean ± SD) | 14.84 ± 2.62 |
SD = Standard Deviation, RRMS = Relapse Remitting Multiple Sclerosis, SPMS = Secondary Progressive Multiple Sclerosis, PPMS = Primary Progressive Multiple Sclerosis, BMI = Body Mass Index, Kg = Kilogram, m = Meter. |
Cognitive and Motor Variables
All data about cognitive function and motor variables are summarized in (Table 2). Memory was the most affected domain, at 84.3%, followed by executive functions and visuospatial skills at 74% and 71.4%, respectively. However, language was the lowest domain, 26%. The worst score of both sides was selected in all motor variables that were examined bilaterally.
Table 2
Participants’ Descriptive Analysis per Parameter
Parameters | MS (n = 70) |
MoCA (Total) (mean ± SD) | 23.51 ± 3.55 |
MoCA Levels (%) Normal (26–30) Mild CI (18–25) Moderate CI (10–17) | 19 (27.1) 47 (67.1) 4 (5.7) |
MoCA Domains (%) Executive Functions Visuospatial Skills Memory Attention Language Orientation | 74 71.4 84.3 65.7 26 41.4 |
Muscle Strength of Upper Extremities | Handgrip strength of Dominant Hand (Kg) (mean ± SD) | 23.41 ± 6.65 |
Handgrip strength of Non-Dominant Hand (Kg) (mean ± SD) | 22.74 ± 7.44 |
Muscle Strength of Lower Extremities | RT-Knee Extensors (Quadriceps) strength (Kg) (mean ± SD) | 26.91 ± 8.52 |
LT-Knee Extensors (Quadriceps) strength (Kg) (mean ± SD) | 26.24 ± 8.22 |
Motor Coordination of Upper Extremities | Supination/Pronation of Dominant Hand (sec) (mean ± SD) | 06.93 ± 01.74 |
Supination/Pronation of Non-Dominant Hand (sec) (mean ± SD) | 07.11 ± 01.75 |
Motor Coordination of Lower Extremities | RT-Heel-to-Knee (sec) (mean ± SD) | 17.15 ± 06.66 |
LT-Heel-to-Knee (sec) (mean ± SD) | 15.49 ± 05.89 |
POMA-B Total Score (mean ± SD) | 13.00 ± 3.67 |
POMA-G Total Score (mean ± SD) | 8.76 ± 3.26 |
Overall Score of POMA (mean ± SD) Low Fall Risk [n (%)] Moderate Fall Risk [n (%)] High Fall Risk [n (%)] | 21.81 ± 6.66 40 (57.1) 11 (15.7) 19 (27.1) |
MoCA = Montreal Cognitive Assessment Scale, Rt = Right side, Lt = Left side, POMA−B = Balance component of POMA, POMA−G = Gait component of POMA. SD = Standard Deviation. |
Correlation Between Cognitive Performance (MoCA) and Motor Function
Muscle Strength
No significant correlations were found between the MoCA and muscle strength of the handgrip (ρ = 0.179, n = 70, p = 0.139) and knee extension (r = 0.146, n = 70, p = 0.227). While handgrip strength has a positive moderate correlation with the language domain (ρ = .434, n = 70, p ˂ 0.001) and low correlation with attention (ρ = .314, n = 70, p = 0.008). Knee extension strength has no correlation with any of the cognitive domain (p ˃ 0.05).
Motor Coordination
There was a negative moderate correlation between the MoCA and motor coordination of upper extremity and a negative low correlation with the motor coordination of lower extremity (r = -0.412, n = 70, p ˂ 0.001, ρ = -0.260, n = 70, p = 0.030, respectively). Moreover, upper extremity coordination was shown negative low correlations with the language domain (ρ = − .296, n = 70, p = 0.013), memory (ρ = − 0.280, n = 70, p = 0.019), visuospatial skills (ρ = − .278, n = 70, p = 0.02), and executive function (ρ = − .287, n = 70, p = 0.016). While Lower extremity coordination has a low negative correlation with the language domain only (ρ = − .308, n = 70, p = 0.010).
Balance, Gait, and Risk of Fall
A positive moderate correlation was found between the MoCA and the total POMA score (ρ = 0.468, n = 70, p ˂ 0.000). POMA subscales also showed positive moderate correlations with the MoCA (ρ = 0.445, n = 70, p ˂ 0.000 for balance, ρ = 0.440, n = 70, p ˂ 0.001 for gait). Specifically, balance has positive low correlations with all cognitive domains (language (ρ = .318, n = 70, p = 0.007), orientation (ρ = .325, n = 70, p = 0.006), memory (ρ = .318, n = 70, p = 0.007), visuospatial skills (ρ = .312, n = 70, p = 0.009), and executive function (ρ = .262, n = 70, p = 0.028)) except attention (ρ = 0.201, n = 70, p = 0.095). Further, gait also has positive low correlations with all cognitive domains (language (ρ = .272, n = 70, p = 0.023), orientation (ρ = .248, n = 70, p = 0.039), memory (ρ = .300, n = 70, p = 0.011), and visuospatial skills (ρ = .293, n = 70, p = 0.014), except attention and executive function domains (ρ = .222, n = 70, p = 0.065, ρ = .214, n = 70, p = 0.075, respectively). Moreover, Fall risk was shown positive low correlations with all cognitive domains (language (ρ = .316, n = 70, p = 0.008), orientation (ρ = .277, n = 70, p = 0.020), memory (ρ = .307, n = 70, p = 0.010), visuospatial skills (ρ = .319, n = 70, p = 0.007), and executive functions (ρ = .242, n = 70, p = 0.044)) except attention (ρ = .233, n = 70, p = 0.053).
Motor Predictor Variables
Motor variables that revealed significant correlations with the MoCA were used in a multiple linear regression to determine the predictor variables [35, 36]. Balance (POMA-B) and gait (POMA-G) were excluded from the linear regression because they showed a high correlation with each other (ρ = 0.822, n = 70, p ˂ 0.001), balance (POMA-B) with fall risk (POMA total score) (ρ = 0.931, n = 70, p ˂ 0.001), and gait (POMA-G) with fall risk (POMA total score) (ρ = 0.961, n = 70, p ˂ 0.001). Muscle strength of handgrip and knee extension were additionally excluded because they showed no significant correlation with the MoCA. Using the total score of POMA (fall risk), upper and lower limb coordination variables were entered in the regression analysis as independent variables, and the MoCA was entered as dependent variable. Using the stepwise method, a significant model 1 emerged (F (1, 68) = 14.150, p ˂ 0.001) with an R2 of 0.172 (Table 3). Therefore, 17.2% of the variance in the MoCA was predictable from the overall score of POMA (Fall Risk). In the model 2, (F (2, 67) = 9.814, p ˂ 0.001) with an R2 increased from 0.171 to 0.227 after adding the supination/pronation test which improved the model (Tables 3, 4). Thus, 22.7% of the variance in the MoCA was predictable from the overall score of POMA (Fall Risk) and supination/pronation test (Fig. 1). The statistical equation that describes the best fit of the regression line is:
$$MoCA=24.325 +(.147 \times \left(Fall Risk\right)+(-.539 \times \left(Supination\setminus Pronation\right))$$
(Table 4) Illustrated that with a one-unit increase in the total POMA score, the MoCA score increased by 0.147, which was found to be a significant change (𝑡 (67) = 2.216, 𝑝 < 0.001). Also, with a one-unit increase of the supination/pronation score, the MoCA score decreased by .539, which was found to be a significant change (𝑡 (67) = − 2.169, 𝑝 < 0.001).
Table 3
Multiple Linear regression Model Summary c
Model | R | R Square | Adjusted R Square | Std. Error of the Estimate | F | Sig. |
1 | .415a | .172 | .160 | 3.250 | 14.150 | ˂ .001 |
2 | .476b | .227 | .203 | 3.164 | 9.814 | ˂ .001 |
a. Predictors: Risk of Fall |
b. Predictors: (Constant), Risk of Fall, Supination/Pronation |
c. Dependent Variable: MoCA |
Table 4
Stepwise Multiple Linear Regression Coefficients a.
Model | B | Std. Error | Beta | t | Sig. |
1 | Constant Fall Risk | 18.698 .221 | 1.338 .059 | .415 | 13.973 3.762 | ˂ .001 ˂ .001 |
2 | Constant Fall Risk Supination/Pronation | 24.325 .147 − .539 | 2.903 .066 .248 | .277 − .271 | 8.379 2.216 -2.169 | ˂ .001 .030 .034 |
a. Dependent Variable: MoCA Score |