Table I. Clinical aspects of hypokinetic dysarthria and typical features of voice disorders in Parkinson’s disease. |
|||||
Voice and speech parameters |
Alteration of voice and speech in PD |
Explication |
Clinical implication |
References of current literature |
Note |
Lung function |
Rigidity of the muscles involved in respiration |
Poor coordination in inspiration and expiration |
Weakened inspiration due to the weak inspiratory musculature, with small inspiratory volume |
[49,50] |
|
Voice quality |
Rough voice |
Involuntarily raspy voice sound |
Patient’s compensation mechanism facing the frame stiffness |
[4,6,11,16,20,30] |
|
Hoarseness |
Involuntarily scratchy voice |
Rigidity of the cricothyroid muscle |
[6,31] |
||
Asthenic voice |
Involuntarily weak voice sound |
Associated with an inadequate respiratory support and with a limitation of adduction of the vocal folds |
[16,26] |
||
Breathiness |
Involuntarily whisper voice sound |
Air escape during voice production |
[6,20,31,32] |
No breathiness in PD [4] |
|
Prosody |
Lower loudness level |
Low volume of voice: hypophony |
Increased rigidity of the laryngeal and respiratory muscles |
[7,11,16,18,26] |
|
Decrease phonation range |
Decrease range of frequencies |
Laryngopharyngeal tract hypomobility |
[4,11,12,16,24,26,29] |
||
Monopitch, monoloudness |
Prosodic insufficiency |
Rigidity of the cricothyroid muscle |
[4,7,11,12,22-24,31,33,51] |
||
Acoustic parameters |
High value of F0 |
Altered periodicity of vocal fold vibration and difficulty to achieve a steady-state phonation |
Reduced function of crico-thyroid and crico-arythenoid muscle and high degree of spasticity or flaccidity of laryngeal muscles Increased rigidity of the laryngeal and respiratory muscles, besides the laryngopharyngeal tract hypomobility |
[4,10,14,17,21,23,24,32-35,37] |
|
High value of vF0 |
Altered periodicity of vocal fold vibration and difficulty to achieve a steady-state phonation |
Impaired ability to keep the laryngeal muscles in a fixed position for vowel prolongation Increased rigidity of the laryngeal and respiratory muscles, besides the laryngopharyngeal tract hypomobility |
[12,16,23,26,27,33] |
||
High value of jitter |
Measure of short-term frequency instability and of involuntary changes in frequency |
Irregular contraction of laryngeal muscles during sound production, loss of motor control of the vocal folds, aperiodicity in the acoustic signal |
[7,11,20,24,35,36,52,53] |
No significant difference in jitter between PD and healthy controls [3,11,16,34] |
|
High value of shimmer |
Measure of short-term intensity instability |
Reduced laryngeal control and degenerative changes in laryngeal tissue Breathiness is related to shimmer, less periodic voice and is roughness or hoarseness |
[12,19,21,23,34,35,52,53] |
No significant difference in shimmer between PD and healthy controls [3,4,11,16,18,20,24,34,36,37] |
|
Low NHR |
Perturbation and irregularity in noise/harmonic ratio |
Dysphonia with increased phonatory instability Turbulent noise due to incomplete glottal closure during sound production |
[4,5,7,20,37] |
According to Vizza et al [21] NHR is higher for PD compared to healthy controls According to Holmes et al [11], NHR value is non-significant between patients with PD and healthy controls |
|
Low HNR |
Perturbation and irregularity in harmonic/noise ratio |
Evaluates the degree of hoarseness |
[4,18,23] |
||
High FTRI and fftr |
Alteration of low-frequency modulating component and long-term tremor frequency modulating component |
Trembling voice |
[19] |
||
ATRI and Fatr |
No alteration of low-amplitude-modulating component and long-term tremor amplitude modulation |
No difference with healthy control |
[19] |
||
DVB |
Difficulty to maintain phonation for some time without intervals |
Voice arrests |
[4] |
||
VTI |
Index of breathiness |
High-frequency noise in voice. It is related to turbulence caused by abnormal closure of vocal folds |
[52] |
No statistically significant differences of VTI in patients with PD compared to healthy controls [34] |
|
s/z ratio |
Ratio of length of time a person can sustain the sound ‘s’ divided the length of time a person can sustain the sound ‘z’ |
Correlation with dysphonia |
[4,23] |
According to Bauer et al [3], no significant differences were found for s/z ratio in patients with PD |
|
Decrease MPT |
Reduce period during which a patient can sustain phonation of a vowel sound (< 10 s) |
Respiratory decline, difficulty in glottal closure during speech production, increase muscular tension |
[3,16,29] |
Gamboa et al [4] and Ramig et al [7] fail to detect any statistical difference between patients with PD and healthy controls |
|
ATRI: amplitude tremor intensity index; DVB: degree of voice break; F0: fundamental frequency; Fatr: amplitude tremor frequency; Fftr: fundamental frequency tremor frequency; FTRI: frequency tremor intensity index; jitter: frequency perturbation; MPT: maximum phonation time; NHR: noise to harmonic ratio; PD: individuals with Parkinson’s disease; shimmer: amplitude perturbation; vF0: fundamental frequency variation; VTI: voice turbulence index. |
Figure. Flowchart of the process of initial literature search and extraction of studies meeting the inclusion criteria.
Table II. Demographic and morphological characteristics of patients with Parkinson’s disease |
||||||
Study design |
Sample |
Mean age ± SD (years) |
Duration of disease (years) |
Instruments |
Voice parameters |
|
Gamboa (1997) |
Case-control study |
41 PD (24 m, 17 f) 28 HC (16 m, 12 f) |
69.8 ± 6.8 PD 67.0 ± 6.8 HC |
4.8 ± 3.5 |
Computerized Speech Lab (CLS) Kay Elemetrics |
F0, jitter, shimmer, HNR, MPT, s/z ratio |
Hertrich (1995) |
Case-control study |
24 PD (9 f, 15 m) 25 HC (13 f, 12 m) |
64,5 PD 54.5 HC |
ns |
Computerized Speech Lab (CLS) Kay Elemetrics |
F0, jitter, shimmer, HNR |
Holmes (2000) |
Case-control study |
30 early PD (15 f, 15 m) 30 later PD (15 f, 15 m) 30 HC (15 f, 15 m) |
68.4 PD |
2.4 |
Computerized Speech Lab (CLS) Kay Elemetrics |
F0, SD F0, jitter, shimmer, NHR |
Jiménez-Jiménez (1997) |
Case-control study |
22 PD (12 m, 10 f) 28 HC (16 m, 12 f) |
65.3 ± 12.5 PD 65.8 ± 6.8 HC |
2.5 ± 2.3 |
Computerized Speech Lab (CLS) Kay Elemetrics |
F0, jitter, shimmer, HNR, MPT, s/z ratio |
Lee (2008) |
Case-control study |
19 surgical PD (11 m, 8 f) 10 non-surgical PD (4 m, 6 f) 11 HC (6 f, 5 m) |
63.84 PD 65.36 HC |
ns |
Computerized Speech Lab (CLS) Kay Elemetrics |
F0, vF0, jitter, shimmer, NHR, vAm |
Majdinasab (2016) |
Cross-sectional study |
27 PD (15 m, 12 f) 21 HC (10 m, 11 f) |
61.6 ± 8.9 PD ns HC |
8.6 ± 4.5 |
Software program Praat |
F0, SD F0, shimmer, jitter, HNR |
Midi (2008) |
Case-control study |
20 PD 12 m, 8 f) 20 HC (10 m,10 f) |
61.5 PD 59.4 HC |
4,7 ± 3.0 |
Computerized Speech Lab (CLS) Kay Elemetrics |
F0, vF0, jitter, shimmer, NHR, MPT |
Oguz (2006) |
Prospective study |
14 PD (14 f) 22 HC (22 f) |
65.7 ± 10.6 PD 59.4 ± 10.0 HC |
ns |
Software program Praat |
Jitter, shimmer, HNR |
Rahn (2007) |
Case-control study |
41 PD (20 f, 21 m) 40 HC (22 f, 18 m) |
58 ± 9.7 PD 46.5 ± 9.1 HC |
ns |
National Instruments AT-MIO-16 |
Jitter, shimmer |
Shao (2010) |
Case-control study |
15 PD (ns) 24 HC (13 f, 11 m) |
65.7 ± 10.6 PD 59.4 ± 10.0 HC |
ns |
Computerized Speech Lab (CLS) Kay Elemetrics |
Jitter, shimmer, ATRI, FTRI, Fatr, Fftr |
Silva (2012) |
Cross-sectional study |
27 PD (27 m) 27 HC (27 m) |
59.9 PD 59.4 HC |
ns |
Computerized Speech Lab (CLS) Kay Elemetrics |
F0, jitter, shimmer, NHR |
Skodda (2011) |
Case-control study |
169 PD (97 m, 72 f) 64 HC (31 m, 33 f) |
67.1 PD 65.05 HC |
ns |
Software program Praat |
F0, SD F0 |
Vizza (2018) |
Case-control study |
60 PD (35 m, 25 f) 39 HC (20 m, 19 f) |
67 PD 46 HC |
ns |
Software program Praat |
F0, jitter %, shimmer, NHR |
Zwirner (1991) |
Case-control study |
18 PD (12 m, 6 f) 12 HC (10 m, 2 f) |
68 PD 58 HC |
ns |
Software program C-speech v. 2.1 |
F0, SD F0, jitter, shimmer, NHR |
f: females; F0: fundamental frequency; Fatr: amplitude tremor frequency; Fftr: fundamental frequency tremor frequency; HC: healthy controls; jitter: frequency perturbation; m: males; MPT: maximum phonation time; NHR: noise to harmonic ratio; ns: no specified; PD: Parkinson’s disease patients; shimmer: amplitude perturbation; s/z ratio: s/z consonants ratio; vF0: fundamental frequency variation. |
Table III. Forest plot illustrating the effect of bulbar Parkinson’s disease on jitter (in percentage) when compared to cognitively healthy controls. |
|||||||||||
Number of healthy controls |
Number of PD patients |
Mean healthy controls |
Mean PD patients |
Standard mean differences |
Standard error |
95% CI |
Weight (%) |
||||
Lower limit |
Upper limit |
Fixed |
Random |
||||||||
Gamboa (1997) |
28 |
41 |
0.62 ± 0.12 |
0.98 ± 0.62 |
0.73 |
0.25 |
0.234 |
1.233 |
9.31 |
9.31 |
|
Hertrich (1995) |
25 |
24 |
0.79 ± 0.76 |
1.44 ± 1.03 |
0.70 |
0.29 |
0.126 |
1.293 |
6.93 |
6.93 |
|
Holmes (2000) |
Early PD |
30 |
30 |
1.06 ± 0.89 |
1.21 ± 9.81 |
0.02 |
0.25 |
–0.488 |
0.532 |
8.98 |
8.98 |
Later PD |
30 |
30 |
1.06 ± 0.89 |
2.16 ± 2.83 |
0.51 |
0.25 |
0.00007 |
1.038 |
8.68 |
8.68 |
|
Jiménez-Jiménez (1997) |
28 |
22 |
0.65 ± 0.15 |
1.16 ± 0.81 |
0.91 |
0.29 |
0.324 |
1.510 |
6.70 |
6.70 |
|
Lee (2008) |
Non-surgical PD |
5 |
4 |
0.32 ± 0.11 |
0.42 ± 0.24 |
0.50 |
0.60 |
–0.934 |
1.939 |
1.58 |
1.58 |
Surgical PD |
5 |
11 |
0.32 ± 0.11 |
0.60 ± 0.41 |
0.76 |
0.52 |
–0.369 |
1.894 |
2.10 |
2.10 |
|
Rahn (2007) |
40 |
41 |
0.24 ± 0.27 |
0.67 ± 1.07 |
0.54 |
0.22 |
0.0965 |
0.989 |
11.6 |
11.6 |
|
Majdinasab (2016) |
21 |
27 |
0.18 ± 0.10 |
0.36 ± 0.53 |
0.42 |
0.28 |
–0.157 |
1.008 |
6.96 |
6.96 |
|
Midi (2007) |
20 |
20 |
0.65 ± 0.29 |
1.70 ± 1.61 |
0.89 |
0.32 |
0.231 |
1.549 |
5.51 |
5.51 |
|
Oguz (2006) |
22 |
14 |
0.29 ± 0.14 |
0.50 ± 0.31 |
0.90 |
0.35 |
0.196 |
1.622 |
4.73 |
4.73 |
|
Shao (2010) |
24 |
15 |
0.48 ± 0.20 |
0.80 ± 0.59 |
0.78 |
0.33 |
0.104 |
1.459 |
5.22 |
5.22 |
|
Silva (2012) |
27 |
27 |
1.54 ± 2.83 |
2.32 ± 2.42 |
0.29 |
0.27 |
–0.249 |
0.833 |
8.02 |
8.02 |
|
Vizza (2018) |
39 |
60 |
0.29 ± 0.16 |
0.97 ± 1.92 |
0.45 |
0.20 |
0.0396 |
0.860 |
13.67 |
13.67 |
|
Total random effects |
344 |
366 |
t 7.334 |
p < 0.001 |
0.56 |
0.076 |
0.41 |
0.71 |
100 |
100 |
|
Odds ratio |
0.49 |
||||||||||
95% CI: 95% confidential interval; PD: Parkinson’s disease. |
Table IV. Forest plot illustrating the effect of Parkinson’s disease on shimmer (in percentage and dB) and vF0 when compared to cognitively healthy controls. |
||||||||||||
Number of healthy controls |
Number of PD patients |
Mean healthy controls |
Mean PD patients |
Standard mean differences |
Standard error |
95% CI |
Weight (%) |
|||||
Lower limit |
Upper limit |
Fixed |
Random |
|||||||||
Shimmer (%) |
Holmes (2000) |
Early PD |
30 |
30 |
6.98 ± 4.17 |
9.31 ± 6.75 |
0.41 |
0.25 |
–0.105 |
0.926 |
12.63 |
11.76 |
Later PD |
30 |
30 |
6.98 ± 4.17 |
8.74 ± 5.97 |
0.33 |
0.25 |
–0.177 |
0.850 |
12.72 |
11.81 |
||
Lee (2008) |
Non-surgical PD |
5 |
4 |
2.43 ± 1.72 |
7.00 ± 3.40 |
1.57 |
0.70 |
–0.085 |
3.233 |
1.70 |
2.69 |
|
Surgical PD |
5 |
11 |
2.43 ± 1.72 |
6.61 ± 2.84 |
1.53 |
0.57 |
0.298 |
2.776 |
2.51 |
3.77 |
||
Majdinasab (2016) |
21 |
27 |
2.38 ± 1.60 |
2.85 ± 1.94 |
0.25 |
0.28 |
–0.322 |
0.835 |
10.15 |
10.42 |
||
Midi (2007) |
20 |
20 |
1.89 ± 0.95 |
3.13 ± 1.90 |
0.80 |
0.32 |
0.155 |
1.463 |
8.04 |
9.05 |
||
Oguz (2006) |
22 |
14 |
4.58 ± 2.45 |
5.46 ± 1.90 |
0.38 |
0.33 |
–0.304 |
1.067 |
7.37 |
8.55 |
||
Shao (2010) |
24 |
15 |
1.04 ± 0.84 |
1.90 ± 1.18 |
0.85 |
0.33 |
0.173 |
1.537 |
7.39 |
8.57 |
||
Silva (2012) |
27 |
27 |
7.87 ± 5.55 |
6.43 ± 5.60 |
–0.25 |
0.26 |
–0.795 |
0.286 |
11.55 |
11.21 |
||
Vizza (2018) |
39 |
60 |
3.74 ± 3.14 |
6.04 ± 6.28 |
0.43 |
0.20 |
0.022 |
0.842 |
19.67 |
14.49 |
||
Zwirner (1991) |
12 |
18 |
4.10 ± 0.02 |
6.00 ± 6.60 |
0.35 |
0.36 |
–0.389 |
1.108 |
6.27 |
7.67 |
||
Total random effects |
235 |
256 |
t 3.741 |
p < 0.01 |
0.45 |
0.20 |
0.216 |
0.695 |
100 |
100 |
||
Odds ratio |
0.81 |
|||||||||||
Shimmer (dB) |
Gamboa (1997) |
28 |
41 |
0.41 ± 0.17 |
0.50 ± 0.30 |
0.34 |
0.24 |
–0.139 |
0.835 |
27.33 |
27.33 |
|
Hertrich (1995) |
25 |
24 |
0.30 ± 0.27 |
0.52 ± 0.53 |
0.51 |
0.28 |
–0.064 |
1.086 |
19.94 |
19.94 |
||
Jiménez-Jiménez (1997) |
28 |
22 |
0.23 ± 0.17 |
0.40 ± 0.26 |
0.78 |
0.29 |
0.196 |
1.367 |
19.23 |
19.23 |
||
Rahn (2007) |
40 |
41 |
0.81 ± 0.48 |
0.95 ± 0.98 |
0.17 |
0.22 |
–0.260 |
0.618 |
33.50 |
33.50 |
||
Total random effects |
121 |
128 |
t 3.19 |
p = 0.02 |
0.40 |
0.12 |
0.156 |
0.659 |
100 |
100 |
||
Odds ratio |
0.72 |
|||||||||||
vF0 |
Lee (2008) |
Non-surgical PD |
6 |
6 |
1.35 ± 0.43 |
6.70 ± 8.32 |
0.83 |
0.56 |
–0.408 |
2.085 |
19.42 |
19.42 |
Surgical PD |
6 |
8 |
1.35 ± 0.43 |
1.81 ± 1.19 |
0.45 |
0.51 |
–0.666 |
1.568 |
23.14 |
23.14 |
||
Midi (2007) |
20 |
20 |
0.99 ± 0.24 |
2.58 ± 2.48 |
0.88 |
0.32 |
0.226 |
1.543 |
57.44 |
57.44 |
||
Total random effects |
32 |
34 |
t 3.144 |
p = 0.003 |
0.77 |
0.24 |
0.283 |
1.268 |
100 |
100 |
||
Odds ratio |
0.95 |
|||||||||||
95% CI: 95% confidential interval; PD: Parkinson’s disease; vF0: variation of fundamental frequency. |
Análisis acústico de la voz en la enfermedad de Parkinson: revisión sistemática de la discapacidad vocal y metaanálisis de estudios Objetivo. Revisar de manera exhaustiva la bibliografía referente a la evaluación instrumental cuantitativa de la voz en pacientes con enfermedad de Parkinson (EP) y realizar un metaanálisis para definir las principales características de los trastornos de la voz en la EP. Pacientes y métodos. Búsquedas bibliográficas con las palabras clave ‘Parkinson’ y ‘voice’ en PubMed, EMBASE, Cochrane Library y Web of Science. Los principales criterios de aceptación fueron: EP con confirmación clínica y medición instrumentada de los parámetros de la voz mediante análisis acústico. Resultados. Catorce publicaciones cumplieron los criterios de aceptación y se incluyeron en el metaanálisis. De los datos incorporados al metaanálisis, se dedujo que varios parámetros vocales, como el jitter, el shimmer y la variación de la frecuencia fundamental, presentan variaciones significativas en los pacientes con EP frente a los controles sanos. Se hallaron variaciones significativas de la frecuencia fundamental y de su desviación estándar, del tiempo máximo de fonación y de la razón armónicos-ruido, si bien con una alta heterogeneidad entre los estudios. En cambio, no se observaron variaciones sustanciales de la razón ruido-armónicos, en el índice s/z ni en la variación de la amplitud. Conclusión. El análisis acústico de la voz por medio de un sistema electrónico permite detectar los cambios de los parámetros vocales de cara a predecir el empeoramiento de la enfermedad y elegir una intervención específica. Entre dichos parámetros, el jitter y el shimmer aumentaron significativamente en los pacientes con EP. Palabras clave. Discapacidad. Enfermedad de Parkinson. Metaanálisis. Patología del habla. Revisión sistemática. Voz. |