The evaluation of oral and vocal fold diadochokinesis (DDK) in individuals with voice disorders may contribute to the understanding of factors that affect the balanced vocal production. Scientific studies that make use of this assessment tool support the knowledge advance of this area, reflecting the development of more appropriate therapeutic planning. Objective: To compare the results of oral and vocal fold DDK in dysphonic women and in women without vocal disorders. Material and methods: For this study, 28 voice recordings of women from 19 to 54 years old, diagnosed with dysphonia and submitted to a voice assessment from speech pathologist and otorhinolaryngologist, were used. The control group included 30 nondysphonic women evaluated in prior research from normal adults. The analysis parameters like number and duration of emissions, as well as the regularity of the repetition of syllables "pa", "ta", "ka" and the vowels "a" and "i," were provided by the Advanced Motor Speech Profile program (MSP) Model-5141, version-2.5.2 (KayPentax). The DDK sequence "pataka" was analyzed quantitatively through the Sound Forge 7.0 program, as well as manually with the audio-visual help of sound waves. Average values of oral and vocal fold DDK dysphonic and nondysphonic women were compared using the "t Student" test and were considered significant when p<0.05. Results: The findings showed no significant differences between populations; however, the coefficient of variation of period (CvP) and jitter of period (JittP) average of the "ka," "a" and "i" emissions, respectively, were higher in dysphonic women (CvP=10.42%, 12.79%, 12.05%; JittP=2.05%, 6.05%, 3.63%) compared to the control group (CvP=8.86%; 10.95%, 11.20%; JittP=1.82%, 2.98%, 3.15%). Conclusion: Although the results do not indicate any difficulties in oral and laryngeal motor control in the dysphonic group, the largest instability in vocal fold DDK in the experimental group should be considered, and studies of this ability in individuals with communication disorders must be intensified.

O objetivo deste estudo foi caracterizar as componentes temporais e espectrais dos abalos musculares em diferentes níveis de contração muscular através da acelerometria. Participaram do estudo 15 indivíduos do sexo masculino e 12 do feminino, todos destros. O experimento constou de um teste de carga máxima (CM) que permitiu determinar cinco cargas percentuais administradas durante os testes de força (20%, 40%, 60%, 80% e 100% da CM), em isometria e por oito segundos cada. Um acelerômetro biaxial foi colocado sobre o ventre muscular do bíceps braquial direito. A raiz média quadrática (valor RMS), um parâmetro temporal, e a freqüência média (FME), um parâmetro espectral, foram extraídas dos sinais de acelerometria (sinal de MMG). Estes parâmetros foram analisados nas direções X (perpendicular às fibras) e Y (paralela às fibras). Ambos os grupos apresentaram comportamento decrescente da FME (Y) com a carga, sendo mais pronunciado para o grupo feminino. A variável FME (X), no grupo feminino, apresentou comportamento semelhante à FME (Y), sendo apenas observada diferença estatística significativa entre 20% da CM e todas as demais cargas (p = 0,0022 para 40% e p < 0,0001 para as demais). O grupo masculino não apresentou diferença estatística significativa entre as cargas. O valor RMS (Y) apresentou comportamento crescente com a carga para ambos os grupos, havendo diferenças entre as cargas de 20% e 40% da CM (p = 0,000) e 80%, e 100% da CM (p = 0,01) para o grupo masculino. No entanto, não foi observada diferença estatística significativa entre as cargas para o grupo feminino. Discute-se que durante a contração muscular ocorrem variações não uniformes do diâmetro da fibra, além de oscilações laterais de baixa freqüência. Estas informações parecem ter forte correlação com a tipagem de fibras, o que poderia contribuir para melhor esclarecer os possíveis mecanismos envolvidos durante o processo de gradação da força muscular.

The aim of this study was to characterize the temporal and spectral components of the muscle contractions in different contraction levels through the accelerometry. Fifteen male and twelve female right-handed individuals participated in this study. The trial was constituted by a maximal workload (MW) test that allowed to determine five different workloads (20%, 40%, 60%, 80% and 100% of MW) which, by its turn, allowed to determine five percentage workloads during the strength test (20%, 40%, 60%, 80%, and 100% of the MW) in isometry during eight seconds each of them. A biaxial accelerometer was put on the muscular abdomen of the right brachii biceps muscle. The mean square root (RMS value), a temporal parameter, and the mean frequency (MFE), a spectral parameter were extracted from the accelerometry signals (MMG signals). Such parameters were analyzed towards the X (perpendicular to the fibers) and Y (parallel to the fibers) directions. Both groups presented a descent behavior pattern of the loaded MFE (Y), and the most accentuated was the female group. The MFE variable (X) in the female group presented similar behavior before the MFE (Y), and it was observed a statistically significant difference only between 20% of the MW and every other workload (p = 0.0022 for 40% and p < 0.0001 for the remaining). The male group did not present any statistically significant difference between workloads. The RMS value (Y) presented an ascent behavior with the workload in both genders, presenting differences between the 20% and 40% workloads of the MW (p = 0.000), and 80% and 100% of the MW (p = 0.01) in the male group. But it was observed no statistically significant difference between workloads in the female group. It is argued that during the muscular contraction, there is non-uniform variations on the fiber's diameter, besides the low frequency lateral oscillations. Such information seems to have strong correlation between the type of the fibers, and this could contribute for a better clarification on the possible mechanisms involved in the gradation process of the muscular strength.

El objetivo de este estudio fué el de caracterizar los componentes temporales y espectrales de las alteraciones musculares en diferentes niveles de la contracción muscular a través de la acelerometría. Participaron del estudio 15 individuos del sexo masculino y 12 del sexo femenino todos diestros. El experimento constó de un test de carga máxima (CM) que permitió determinar cinco cargas porcentuales administradas durante los tests de fuerza (20%, 40%, 60%, 80% y 100% de la CM), en isometría y por ocho segundos cada una. Un acelerómetro biaxial fué colocado sobre el vientre muscular del bíceps braquial derecho. La raiz média cuadrada (valor RMS), un parámetro temporal, y la frecuencia média (FME), un parámetro espectral, fueron obtenidas de los señales de acelerometría (señal de MMG). Estos parámetros fueron analizados en las direcciones X (perpendicular a las fibras) e Y (paralela a las fibras). Ambos grupos presentaron un comportamiento decreciente de la FME (Y) con una carga, siendo mas pronunciado para el grupo femenino. La variáble FME (X), en el grupo femenino, presentó um comportamiento semejante a la FME (Y), siendo apenas observada diferencia estadísticamente significativa entre 20% de la CM y todas las demas cargas (p = 0,0022 para 40% y p < 0,0001 para las demás). El grupo masculino no presentó diferencia estadística significativa entre las cargas. El valor RMS (Y) presentó comportamiento creciente con la carga para ambos grupos, habiendo diferencias entre las cargas de 20% y 40% de la CM (p = 0,000) e 80%, e 100% de la CM (p = 0,01) para o grupo masculino. No obstante, no se observó diferencia estadística significativa entre las cargas para el grupo femenino. Se discute que durante la contracción muscular ocurren variaciones no uniformes del diámetro de la fibra, a parte de las oscilaciones laterales de baja frecuencia. Estas informaciones parecen tener fuerte correlación con un tipo de fibras, que podria contribuir para aclarar mejor los posibles mecanismo del processo durante el proceso de graduación de la fuerza muscular.