Table 2.
Quantitative Analysis of (a) Balance and (b) Gait in ET
| First Author, Year | ET (n) Control (n) | Age (Years) | Method | Outcomes | Results |
|---|---|---|---|---|---|
| (a) Studies on quantitative assessment of balance (listed chronologically) | |||||
| Bove et al.12 | 19 ET; 19 control |
64.1 59.9 |
QP (Quiet stance, cognitive and motor dual task, eyes open and closed) | 1. Center of pressure (COP) area; 2. COP path; 3. COP x displacement; 4. COP y displacement | COP path was greater in ET with head tremor; COP area and path increased with eyes closed and during dual cognitive or motor task in both groups |
| Parisi et al.20 | 16 ET head tremor, 14 ET no head tremor; 28 control |
59.4 57.1 58.4 |
QP (stance eyes open and closed) | 1. Tremor score; 2. Falls; 3. Near falls; 4. COP displacement; 5. COP speed | There were no significant differences in COP sway and speed between ET and controls |
| Hoscovcova et al.13 | 30 ET 25 control |
55.8 53.0 |
Tremor score; clinical tests of balance (ABC, FAB); QP (normal and tandem stance) | 1. Tremor rating scale; 2. ICARS; 3. ABC scale; 4. Fullerton advanced balance scale; 5. Acceleration amplitude; 6. Acceleration frequency; 7. Stride length; 8. Cycle time; 9. Support base; 10. Swing time; 11. Stance time; 12. Velocity; 13. Tandem missteps; 14. Sway path; 15. Sway path; 16. COP area | No differences between ET and controls during normal gait; during tandem gait, ET patients had lower velocity and more missteps; COP area was higher in ET during tandem stance; no differences between groups on clinical tests (ABC and FAB) |
| (b) Studies on quantitative assessment of gait (listed chronologically) | |||||
| Stolze et al.19 | 25 ET; 8 Cerebellar; 21 control |
50.3 52.5 52.7 |
QG (preferred speed); TW; tremor score | 1. Total tremor score; 2. Gait speed; 3. Stride length; 4. Cadence; 5. Step width; 6. Foot angle; 7. Step height; 8. Stance time; 9. Swing time; 10. Double support time; 11. CoV; 12. Tandem missteps | Preferred walk: ET patients walked with greater step width; Tandem walk: ET patients had wider step width and more missteps than controls; Step width and tandem missteps were associated with intention tremor |
| Kronenbuerger et al.14 | 25 ET no DBS; 12 ET DBS; 25 control |
46.3 64.2 46.3 |
QG (preferred and tandem gait on treadmill); QP; | 1. Stride length; 2. Cadence; 3. Stance phase; 4. Number of missteps; 5. Sway area; 6. Falls; | ET had shorter stride length and more missteps; ET had greater sway when vision was absent/sway referenced and platform tilt was sway referenced; DBS did not improve gait and posture |
| Rao et al.15 | 104 ET; 40 control |
86 84.1 |
NE; QG (preferred and tandem walk on GAITRITE) |
1. Gait Speed; 2. Step length; 3. Cadence; 4. Stride time; 5. Double support % 6. Step time difference; 7. Step width; 8. CoV swing length; 9. CoV stride length; 10. Support base; 11. Tandem missteps | In preferred walk, ET had slow speed and cadence, increased double support percent, and increased asymmetry. In tandem walk, ET had more missteps. Gait impairments were worse for ET than controls across age |
| Louis et al.33 | 4 ET | 38–79 | NE; QG (preferred walk on GAITRITE); clinical tests of balance (ABC, POMA) | 1. ABC-6 score; 2. Tinetti POMA score; 3. Gait speed; 4. Percent time in double support; 5. Step time difference; 6. CoV swing time | ABC score and Tinetti POMA score were lower and tandem missteps were higher in ET; gait speed was lower, percent double support, step time difference and CoV swing time were higher |
| Rao et al.17 | 151 ET; 62 control |
84.4 79.6 |
NE; QG (dual task gait on GaitRITE) | 1. Gait speed; 2. Stride length; 3. Cadence; 4. Stride time; 5. Double support time; 6. Step time difference; 7. Step width; 8. CoV Stride length; 9. CoV stride length | Gait most impaired in ET with low cognitive scores (LCS) – less impaired in ET cases with higher cognitive scores (HCS); cognitive motor interference was greatest for ET LCS for double support time, step time difference and CoV stride time |
| Fernandez et al.34 | 24 ET 31 PD; 38 control |
68 68 68 |
QG (force plate) | 1. COP displacement; 2. COP velocity; First step length; 3. First step time; first step speed; | COP displacement in AP direction reduced in ET; length of the first step was reduced in ET |
| Roemmich et al.18 | 31 ET 11 Control |
66.5 63.6 |
QG (preferred walk on treadmill) | Mean and CV for 1. Stride length; 2. Stride time; 3. Step length; 4. Step time; 5. Step width; 6. α (slope of linear least-squares fit) | During preferred walk, ET had slower gait speed and increased variability; during speed matching, ET had higher step width variability; gait variability was associated with midline tremors |
| Rao et al.28 | 132 ET 48 Control |
83.7 79.5 |
NE; ABC; QG (preferred speed GAITRite) | 1. ABC-6 score; 2. Number of falls; 3. Gait speed; 4. Cadence; 5. Step length; 6. Step time difference; 7. Double support %; 8. CoV stride length; 9. CoV stride time | ET with low cognitive scores (LCS) had lower ABC scores and higher number of falls; gait measures correlated with balance confidence and falls; gait speed and ABC-6 score were significant predictors of falls |
| Rao and Louis 16 | 155 ET 60 Control |
81.9 80.1) |
QG (in time with metronome on GAITRite); Tremor score | 1. Cadence; 2. Step time; 3. Cadence error; 4. Cadence SD; 5. Cranial tremor score | Cadence was lower in ET; cadence error (accuracy) and cadence SD (precision) were similar in ET and controls; cadence and cadence error were correlated with cranial tremor score |
Abbreviations: ABC, Activities of Balance Confidence; CoV, Coefficient of Variation; DBS, Deep Brain Stimulation; ET, Essential Tremor; FAB, Fullerton Advanced Balance Assessment; ICARS, International Cooperative Ataxia Rating Scale; NE, Neurological Examination; PD, Parkinson’s Disease; POMA, Performance-Oriented Mobility Assessment; QG, Quantitative Gait; QP, Quantitative Posturography; TUG, Timed Up and Go.