Perceptualand Motor Skills, 1990, 71, 951-954.
O Perceptual and Motor SkiUs 1990
PASSIVE TACTILE STIMULATION EFFECTS O N T H E MUSCLE TONE O F HYPOTONIC, DEVELOPMENTALLY DELAYED YOUNG CHILDREN ' L. W. LINKOUS AND R. M. STUTTS The University of Alabama Summary.-A pilot study was performed with 13 children, 1 to 4 yr. of age, to explore an heretofore uninvestigated area. The effect of passive tactile stimulation was an increase in muscle activation and hence the muscle tone of 13 hypotonic, developmentally delayed children.
The tactile system is the earliest sensory system to become functional (Montagu, 1986). Early intervention programs typically provide active tactile stimulation to increase sensory integration and kinesthetic awareness, to reduce involuntary physical reactions in response to being touched (tactile defensiveness), and to alter muscle tone (Stutts, 1990), but researchers and special educators still seek ways to provide stimulation to young children (Kilgo, Holder-Brown, Johnson, & Cook, 1988). This study explored another method of altering the muscle tone of hypotonic young children. Tactile stimulation requires both movement through (active) and contact with (passive) the environment. The impaired young child may move less often through a relatively stable environmental space to receive less active tactile stimulation. However, even when relatively stationary the developmentally delayed young child can still receive passive tactile stimulation via body contact with environmental objects' surfaces. Active and passive stimulation have value for the growing organism, both human and infrahuman (Harlow, 1958; Pack, 1975; Huss, 19771, but there are no empirical studies which contrast passive and active stimulation before 1989 that specifically related passive stimulation from a textured surface to muscle tone of young children (Stutts, 1990). A general goal of intervention with young children is to minimize effects of physical impairment. One specific objective is to increase the muscle tone of hypotonic young children. Methods for increasing muscle tone are somewhat experimental, but current programs for these young children who lack normal muscle tone rarely include planned, programmed, passive tactile stimulation. Instead, early childhood special education stimulation programs typically provide large amounts of motoric stimulation, physical facilitation, and other methods of active tactile stimulation (Stutts, 1990).
'Address correspondence to L. W. Linkous, Box 870231, The University of Alabama, Tuscaloosa, AL 35487-0231.
95 2
L. W. LINKOUS & R. M. STUTTS
The rationale for this study was that, if one aspect of motor impairment is inadequate muscle tone and if passive tactile stimulation from surface textures could increase muscle tone as indicated by higher electromyographlc (EMG) readings for hypotonic, developmentally delayed children, then selection of appropriate surface textures for environmental objects could become a programmatic decision. as I n this study, muscle tone was defined for sample selection purposes . hypotonic or not hypotonic on the basis of the current medical assessment record and the concurrent professional judgment of certified physical and occupational therapists. Using an E M G reading for each young child on the covered-slick surface as a reference point, change in muscle tone was operationally defined as a difference in the E M G readings for each child on each subsequent surface. The purpose of this pilot study was to assess whether surface textures other than the usual slick vinyl or naugahide coverings of frequently used apparatus would increase muscle tone for hypotonic chddren. The vinyl on apparatus such as positioning boards, prone boards, and chairs used by hypotonic children apparently makes cleaning easier, but these surfaces are often covered with a sheet or towel to absorb fluids. The question was whether passive tactile stimulation from selected surface textures would generate statistically significant differences in muscle tone of young developmentally delayed children as measured by electromyography. If so, in addition to these practical concerns, passive tactile stimlation to alter muscle tone should be a programmatic issue. All subjects were enrolled full time in an infant stimulation program along with 26 other young children. The decision to include a child i n the study was based upon hypotonic muscle tone regardless of additional physical or mental impairments. Muscle tone was assessed from medical and other assessment records plus the evaluations of the certified physical and occupational therapists. Thirteen subjects began and participated to the completion of the study. Six children were diagnosed Down Syndrome; the other children had rare conditions. Seven children were 1 yr. old or younger, four more were between 1% yr. and 3 yr. old, another was 3 % yr. old, and the oldest one was 4 yr. of age. All experimental surfaces were black and composed of the following materials: (a) slick, uncovered vinyl, (b) covered, vinyl covered with high grade cotton sheeting, (c) fuzzy, a soft plush bath mat of high luster velvet pile made with two-ply nylon yarn and having a latex backing, (d) covered rough, rubber doormats covered with high grade cotton sheeting, and (e) rough, a standard rubber doormat. Each of the surfaces were placed on a gymnasium mat located in a naproom. E M G readings were made on the subjects with a dual-channel surface - -
PASSIVE TACTILE STIMULATION OF MUSCLE
95 3
electromyograph. The adhesive surface of an electrode triangle was attached anatomically to the fibers of the trapezius, the muscle to be tested, and midway between the origin and the insertion of the muscle at the approximate location of the motor point recommended by Warfel (1985) and illustrated by Goodgold (1986). All testing was done while the subject was in a prone position. While the subject was relatively still, the e l e ~ t r o m ~ o g r a p h was monitored for 2 min. per surface with 10 measurements recorded per surface. Measurement was repeated and recorded for 10 days with each of the surfaces tested an equal number of times. There were a total of 500 readings per child. Before beginning this study, the covered-slick surface was ascertained to be the most neutral surface for these children; it was presented first. Then followed in a random order the remaining surfaces: the slick, fuzzy, coveredrough, and rough surfaces. The random order of the surface presentation was determined before testing each day. The design of the study was a single-factor, repeated-measures design, with each subject as his own control. The independent variable was the texture of the surfaces. The five levels of the independent variable were known to be at least partially ordered. The dependent variable was the surface E M G value of muscle tone as measured in microvolts. A mean of each child's E M G readings per surface was computed. Ranking transformations were used because the data were not expected to meet the assumptions for parametric statistics. The heterogeneous group of children would probably generate data that violated the assumption of homoscedasticity. Kendall's Coefficient of Concordance (W), an estimate of the association of subjects' responses to each surface, was computed first. This was followed by an F statistic suggested by Hora and Conover (1984) who recommended analysis of variance of over-all ranks as a straightforward method for assessing ranked data differences. The value of Kendall's W was .82 ( p < .001), permitting the rejection of the statistical null hypothesis. When the data were ranked without regard to row or column, an analysis of variance yielded an F ratio of 12.45 ( p < ,001). Both statistical procedures established that these results were not due to chance but indicated that texture did affect measured muscle tone. As the surfaces upon which the children lay became more textured, the muscle tone increased significantly. The surfaces with the least texture, covered-slick and slick, had the lowest E M G readings. The covered-rough and rough surfaces had the highest readings. A limitation of this study was that young children are inherently variable. The decision to take readings when the subject was relatively still was based on experience and was a judgment call. The small sample was only partially offset by the extended measurements. However, the results were so
954
L. W. LINKOUS & R. M. STUTTS
consistent that one can infer the following conclusion within the limitations of this pilot study. Covering the equipment with which young hypotonic children come in contact may assist with occurrence of increased muscle tone. The incorporation of interchangeable surfaces of varying textures may provide a varied stimulation for handicapped children. The simple act of lying prone on the textured surfaces produced enough change in the EMG that mean ranks of the tone in one muscle, the trapezius, changed as the surface textures changed. Young hypotonic, developmentally delayed children should be exposed systematically to body contacr with highly textured surfaces. Since one goal of therapy for hypotonic children is to increase the muscle tone for greater support and locomotion, the provision of textured surfaces may be beneficial in conjunction with other therapies. Further research with additional surface textures is planned. Passive tactile stimulation of developmentally delayed children should not be left to chance but should be a deliberate intervention. REFERENCES
GOODGOLD, J. (1986) Anatomical correlates of clinical electromyography. (2nd ed.) Baltimore,
MD: Williams
& Wilkins.
HARLOW, H. F. (1958) The narure of love. American Psychologist, 13, 673-685. HORA, S. C., & CONOVER, W. J. (1984) The F statistic in the two-way layout with rank-scale transformed data. Jozrrnal of The American Stntistical Association, 79, 387, 668-673.
Huss, A. J. (1977) Touch with care or a caring touch. The American Joirrnal of Occupational Therapy, 31, 11-18.
KILGO,J., HOLDER-BROWN, L., JOHNSON, L. J., & COOK,M. J. (1988) An examination of the effect of tactile-kinesthetic stimulation on the developmenr of preterm infants. Journal ofthe Division for Early Childhood, 12, 320-327. MONTAGU, A . (1986) Tozrching: the human significance of the skin. (3rd ed.) New York: Harper & Row.
PACK,D. G. (1975) Textural references in six-to-eleven-month-old infants. Unpublished master's thesis, Univer. of Alabama, Tuscaloosa, Alabama. STUTTS, R. M. (1990) Measured responses to textured surfaces by young hypotonic children. Unpublished doctoral dissertation, Univer. of Alabama, Tuscaloosa, Alabama. WARFEL,J. H . (1985) The exhmmitjes: mzrscles and motor points. Philadelphia, PA: Lea & Febiger. Accepted October 22, 1990.
O Perceptual and Motor SkiUs 1990
PASSIVE TACTILE STIMULATION EFFECTS O N T H E MUSCLE TONE O F HYPOTONIC, DEVELOPMENTALLY DELAYED YOUNG CHILDREN ' L. W. LINKOUS AND R. M. STUTTS The University of Alabama Summary.-A pilot study was performed with 13 children, 1 to 4 yr. of age, to explore an heretofore uninvestigated area. The effect of passive tactile stimulation was an increase in muscle activation and hence the muscle tone of 13 hypotonic, developmentally delayed children.
The tactile system is the earliest sensory system to become functional (Montagu, 1986). Early intervention programs typically provide active tactile stimulation to increase sensory integration and kinesthetic awareness, to reduce involuntary physical reactions in response to being touched (tactile defensiveness), and to alter muscle tone (Stutts, 1990), but researchers and special educators still seek ways to provide stimulation to young children (Kilgo, Holder-Brown, Johnson, & Cook, 1988). This study explored another method of altering the muscle tone of hypotonic young children. Tactile stimulation requires both movement through (active) and contact with (passive) the environment. The impaired young child may move less often through a relatively stable environmental space to receive less active tactile stimulation. However, even when relatively stationary the developmentally delayed young child can still receive passive tactile stimulation via body contact with environmental objects' surfaces. Active and passive stimulation have value for the growing organism, both human and infrahuman (Harlow, 1958; Pack, 1975; Huss, 19771, but there are no empirical studies which contrast passive and active stimulation before 1989 that specifically related passive stimulation from a textured surface to muscle tone of young children (Stutts, 1990). A general goal of intervention with young children is to minimize effects of physical impairment. One specific objective is to increase the muscle tone of hypotonic young children. Methods for increasing muscle tone are somewhat experimental, but current programs for these young children who lack normal muscle tone rarely include planned, programmed, passive tactile stimulation. Instead, early childhood special education stimulation programs typically provide large amounts of motoric stimulation, physical facilitation, and other methods of active tactile stimulation (Stutts, 1990).
'Address correspondence to L. W. Linkous, Box 870231, The University of Alabama, Tuscaloosa, AL 35487-0231.
95 2
L. W. LINKOUS & R. M. STUTTS
The rationale for this study was that, if one aspect of motor impairment is inadequate muscle tone and if passive tactile stimulation from surface textures could increase muscle tone as indicated by higher electromyographlc (EMG) readings for hypotonic, developmentally delayed children, then selection of appropriate surface textures for environmental objects could become a programmatic decision. as I n this study, muscle tone was defined for sample selection purposes . hypotonic or not hypotonic on the basis of the current medical assessment record and the concurrent professional judgment of certified physical and occupational therapists. Using an E M G reading for each young child on the covered-slick surface as a reference point, change in muscle tone was operationally defined as a difference in the E M G readings for each child on each subsequent surface. The purpose of this pilot study was to assess whether surface textures other than the usual slick vinyl or naugahide coverings of frequently used apparatus would increase muscle tone for hypotonic chddren. The vinyl on apparatus such as positioning boards, prone boards, and chairs used by hypotonic children apparently makes cleaning easier, but these surfaces are often covered with a sheet or towel to absorb fluids. The question was whether passive tactile stimulation from selected surface textures would generate statistically significant differences in muscle tone of young developmentally delayed children as measured by electromyography. If so, in addition to these practical concerns, passive tactile stimlation to alter muscle tone should be a programmatic issue. All subjects were enrolled full time in an infant stimulation program along with 26 other young children. The decision to include a child i n the study was based upon hypotonic muscle tone regardless of additional physical or mental impairments. Muscle tone was assessed from medical and other assessment records plus the evaluations of the certified physical and occupational therapists. Thirteen subjects began and participated to the completion of the study. Six children were diagnosed Down Syndrome; the other children had rare conditions. Seven children were 1 yr. old or younger, four more were between 1% yr. and 3 yr. old, another was 3 % yr. old, and the oldest one was 4 yr. of age. All experimental surfaces were black and composed of the following materials: (a) slick, uncovered vinyl, (b) covered, vinyl covered with high grade cotton sheeting, (c) fuzzy, a soft plush bath mat of high luster velvet pile made with two-ply nylon yarn and having a latex backing, (d) covered rough, rubber doormats covered with high grade cotton sheeting, and (e) rough, a standard rubber doormat. Each of the surfaces were placed on a gymnasium mat located in a naproom. E M G readings were made on the subjects with a dual-channel surface - -
PASSIVE TACTILE STIMULATION OF MUSCLE
95 3
electromyograph. The adhesive surface of an electrode triangle was attached anatomically to the fibers of the trapezius, the muscle to be tested, and midway between the origin and the insertion of the muscle at the approximate location of the motor point recommended by Warfel (1985) and illustrated by Goodgold (1986). All testing was done while the subject was in a prone position. While the subject was relatively still, the e l e ~ t r o m ~ o g r a p h was monitored for 2 min. per surface with 10 measurements recorded per surface. Measurement was repeated and recorded for 10 days with each of the surfaces tested an equal number of times. There were a total of 500 readings per child. Before beginning this study, the covered-slick surface was ascertained to be the most neutral surface for these children; it was presented first. Then followed in a random order the remaining surfaces: the slick, fuzzy, coveredrough, and rough surfaces. The random order of the surface presentation was determined before testing each day. The design of the study was a single-factor, repeated-measures design, with each subject as his own control. The independent variable was the texture of the surfaces. The five levels of the independent variable were known to be at least partially ordered. The dependent variable was the surface E M G value of muscle tone as measured in microvolts. A mean of each child's E M G readings per surface was computed. Ranking transformations were used because the data were not expected to meet the assumptions for parametric statistics. The heterogeneous group of children would probably generate data that violated the assumption of homoscedasticity. Kendall's Coefficient of Concordance (W), an estimate of the association of subjects' responses to each surface, was computed first. This was followed by an F statistic suggested by Hora and Conover (1984) who recommended analysis of variance of over-all ranks as a straightforward method for assessing ranked data differences. The value of Kendall's W was .82 ( p < .001), permitting the rejection of the statistical null hypothesis. When the data were ranked without regard to row or column, an analysis of variance yielded an F ratio of 12.45 ( p < ,001). Both statistical procedures established that these results were not due to chance but indicated that texture did affect measured muscle tone. As the surfaces upon which the children lay became more textured, the muscle tone increased significantly. The surfaces with the least texture, covered-slick and slick, had the lowest E M G readings. The covered-rough and rough surfaces had the highest readings. A limitation of this study was that young children are inherently variable. The decision to take readings when the subject was relatively still was based on experience and was a judgment call. The small sample was only partially offset by the extended measurements. However, the results were so
954
L. W. LINKOUS & R. M. STUTTS
consistent that one can infer the following conclusion within the limitations of this pilot study. Covering the equipment with which young hypotonic children come in contact may assist with occurrence of increased muscle tone. The incorporation of interchangeable surfaces of varying textures may provide a varied stimulation for handicapped children. The simple act of lying prone on the textured surfaces produced enough change in the EMG that mean ranks of the tone in one muscle, the trapezius, changed as the surface textures changed. Young hypotonic, developmentally delayed children should be exposed systematically to body contacr with highly textured surfaces. Since one goal of therapy for hypotonic children is to increase the muscle tone for greater support and locomotion, the provision of textured surfaces may be beneficial in conjunction with other therapies. Further research with additional surface textures is planned. Passive tactile stimulation of developmentally delayed children should not be left to chance but should be a deliberate intervention. REFERENCES
GOODGOLD, J. (1986) Anatomical correlates of clinical electromyography. (2nd ed.) Baltimore,
MD: Williams
& Wilkins.
HARLOW, H. F. (1958) The narure of love. American Psychologist, 13, 673-685. HORA, S. C., & CONOVER, W. J. (1984) The F statistic in the two-way layout with rank-scale transformed data. Jozrrnal of The American Stntistical Association, 79, 387, 668-673.
Huss, A. J. (1977) Touch with care or a caring touch. The American Joirrnal of Occupational Therapy, 31, 11-18.
KILGO,J., HOLDER-BROWN, L., JOHNSON, L. J., & COOK,M. J. (1988) An examination of the effect of tactile-kinesthetic stimulation on the developmenr of preterm infants. Journal ofthe Division for Early Childhood, 12, 320-327. MONTAGU, A . (1986) Tozrching: the human significance of the skin. (3rd ed.) New York: Harper & Row.
PACK,D. G. (1975) Textural references in six-to-eleven-month-old infants. Unpublished master's thesis, Univer. of Alabama, Tuscaloosa, Alabama. STUTTS, R. M. (1990) Measured responses to textured surfaces by young hypotonic children. Unpublished doctoral dissertation, Univer. of Alabama, Tuscaloosa, Alabama. WARFEL,J. H . (1985) The exhmmitjes: mzrscles and motor points. Philadelphia, PA: Lea & Febiger. Accepted October 22, 1990.
