BRAIN
AND
LANGUAGE
4, 588-590 (1977)
Development of Crossed and Uncrossed Localization on the Fingers DAVID Langley
GALIN,
ROBERT DIAMOND,
Porter Institute,
University
AND JEANNINE
of California
Tactile HERRON
at San Francisco
The ability to identify or localize a designated finger in some form has been linked to quite different cognitive abilities such as reading, writing, calculation, and speech, and developmental changes in some of these “finger localization” tests have been studied (Gerstmann, 1940; Benton, 1959, 1977a, b; Kinsbourne & Warrington, 1963; Strub & Geschwind, 1974; Satz, Friel, & Rudegair, 1974; Lefford, Birch, & Green, 1974). Unfortunately the name “finger localization” has been used for test procedures which differ greatly in their requirements for memory, simple somesthetic discrimination, naming, symbolic manipulations, right-left orientation, and appreciation of symmetry. Since some authors have suggested that performance on these tests has great predictive value for performance on other cognitive tasks at later ages (for example, dyslexia, Satz et al., 1974; “scholastic failure,” Lefford et al., 1974), it is important to know which aspects of the finger testing are relevant. Studies which have aimed at defining the neuropsychological components which enter into the various forms of finger tests have not considered the possible role of hemispheric interactions, such as crossed inhibition or the ability to transfer information from one hemisphere to the other. This would seem particularly important in tests where one hand is touched and the other hand is used to point to the spot touched or to the corresponding location on a model. Although there has been little study of the maturation of function of the corpus callosum and other forebrain commissures, we do know that these systems are late to myelinate (Yakovlev & Lecours, 1967; Myerson, 1968), and we might infer that the ability to transfer tactile information from one hemisphere to the other changes significantly with age. Therefore, it seemed useful to us to investigate the development of crossed and uncrossed localization on the fingers. We have tested 108 children between 4 years 9 months and 10 years 1 This research was supported in part by Grant NIMH 28456 and Public Health Service Biomedical Research Support Grant RR05755. Requests for reprints should be sent to Dr. David Galin, Langley Porter Neuropsychiatric Institute, University of California at San Francisco, 401 Pamassus Avenue, San Francisco, California 94143. The authors wish to thank California Democratic Assemblyman John Vasconcellos for his encouragement and support of this work. 588 Copyright All riehts
0 1977 by Academic Press. Inc. of retxoduction in anv form reserved.
DEVELOPMENT
OF FINGER TABLE
589
LOCALIZATION
1
TACTILE LOCALIZATION ON THE FINGERS:CROSSEDAND UNCROSSED Age number
4/9”-5111 (n = 16)
6/O-6111 (n = 11)
710-7111 (n = 25)
S/O-8/11 (n = 25)
9/o-9/ 11 (n = 25)
10/o- IO/l I (n = 6)
2.94
1.82
1.08
0.40
0.08
0.17
1.95
1.99
1.38
0.63
0.27
0.37
20.56
13.55
9.08
5.84
4.00
0.67
8.52
9.07
8.82
4.00
2.74
0.75
Total errors Uncrossed Mean Standard deviation Crossed Mean Standard deviation
B First number indicates years; second number indicates months.
month of age, of both sexes, from upper middle class backgrounds. All children with known neurological or behavioral problems were excluded. The child’s hands, palms facing each other, were hidden from his view by a cloth screen, and his eyes were closed. The examiner lightly touched one of ten points on the fingers (proximal, middle, or distal phalanx of each finger, excluding distal index finger and proximal little finger). The child was asked to touch that spot with the thumb of the same hand (‘Irncrossed localization”) or to touch the homologous spot on the opposite hand with the opposite thumb (“crossed localization”). Both finger and joint errors were recorded. There were 40 trials given, 20 for each hand, and 10 each crossed and uncrossed, in counterbalanced orders. We found more crossed than uncrossed errors, for all ages tested, but the difference was strongly age dependent; the younger the child the greater the difference. Even the youngest age group made few uncrossed errors (usually less than five) but averaged over 20 crossed errors. By age 8 or 9 most children made no uncrossed errors and less than six crossed errors. The same pattern of results was seen for the joint errors analyzed alone. These results could be interpreted as showing developmental improvement in interhemispheric transfer of information, perhaps related to progressive myelination or other aspects of maturation of the forebrain commissural neurons. Since the child can perform well on the task in the uncrossed condition it is clear that he understands and can comply with the instructions and meet the motor demands. Other abilities which contribute to tactile localization are known to improve with age, such as appreciation of symmetry or differentiation of body image, but it is difficult to see how they would apply more to crossed than to uncrossed localization. One might suspect that the crossed task offers an opportunity for a left-
590
GALIN, DIAMOND, AND HERRON
right confusion in the order of the fingers; with palms up, on the left hand the middle finger is left of the ring finger, on the right hand the middle finger is right of the ring finger. To reduce this possibility we tested the children with palms facing each other: In this position the fingers of both hands are in the same up-down orientation to each other, eliminating the reversal in left-right orientation. In any case this problem cannot apply to the joint errors, which show the same effect. The interpretation of developmental improvement in interhemispheric information transfer is given some further encouragement by our pilot experiments on crossed and uncrossed object retrieval in children. We have used fabrics of different textures; the child feels a fabric and must retrieve by touch a matching fabric from a container of samples with the same hand or the opposite hand. As with the finger localization task, we find more crossed than uncrossed errors, with the difference greatest in the youngest group. Further research in this area seems warranted. If it is confirmed that maturation of hemispheric interaction is one of the components affecting performance on crossed tactile localization, it still remains to be seen whether this is a relevant component of those “finger localization” tests which predict later cognitive performance. REFERENCES Benton, A. L. 1959. Right-left discrimination pathology. New York: Hoeber-Harper.
and finger
localization:
Development
and
Benton, A. L. 1977a. Neuropsychological significance of finger recognition. In M. Bortner (Ed.), Toward theories of cognitive development, essays in memory of Herbert Birch. In press. Benton, A. L. 1977b. Reflections on the Gerstmann syndrome. Brain and Language, 4, 45-62. Gerstmann, J. 1940. Syndrome of finger agnosia, disorientation for right and left, agraphia and acalculia. Archives of Neurology and Psychiatry, 44, 398-408. Kinsboume, M., & Warrington, E. K. 1963. Developmental factors in reading and writing backwardness. British Journal of Psychology, 15, 132- 137. Lefford, A., Birch, H. G., & Green, G. 1974. The perceptual and cognitive bases for finger localization and selective finger movement in preschool children. Child Development, 45, 335-343. Meyerson, B. A. 1968. Ontogeny of interhemispheric functions. Acta Physiologica Scandinavica, 73, 5- 108. Satz, P., Friel, J., & Rudegair, F. 1974. Differential changes in the acquisition of developmental skills in children who later become dyslexic: A three year follow-up. In D. G. Stein, J. J. Rosen, &N. Butter (Eds.), Plasticity and recovery offunction in the central nervous system. New York: Academic Press. Strub, R., & Geschwind, N. 1974. Gerstmann syndrome without aphasia. Cortex, 10,378387. Yakovlov, P. I., & Lecours, A. 1%7. The myelogenetic cycles of regional maturation of the brain. In A. Minkowski (Ed.), Regional development of the brain in early life. London: Blackwell Scientific Publications.
AND
LANGUAGE
4, 588-590 (1977)
Development of Crossed and Uncrossed Localization on the Fingers DAVID Langley
GALIN,
ROBERT DIAMOND,
Porter Institute,
University
AND JEANNINE
of California
Tactile HERRON
at San Francisco
The ability to identify or localize a designated finger in some form has been linked to quite different cognitive abilities such as reading, writing, calculation, and speech, and developmental changes in some of these “finger localization” tests have been studied (Gerstmann, 1940; Benton, 1959, 1977a, b; Kinsbourne & Warrington, 1963; Strub & Geschwind, 1974; Satz, Friel, & Rudegair, 1974; Lefford, Birch, & Green, 1974). Unfortunately the name “finger localization” has been used for test procedures which differ greatly in their requirements for memory, simple somesthetic discrimination, naming, symbolic manipulations, right-left orientation, and appreciation of symmetry. Since some authors have suggested that performance on these tests has great predictive value for performance on other cognitive tasks at later ages (for example, dyslexia, Satz et al., 1974; “scholastic failure,” Lefford et al., 1974), it is important to know which aspects of the finger testing are relevant. Studies which have aimed at defining the neuropsychological components which enter into the various forms of finger tests have not considered the possible role of hemispheric interactions, such as crossed inhibition or the ability to transfer information from one hemisphere to the other. This would seem particularly important in tests where one hand is touched and the other hand is used to point to the spot touched or to the corresponding location on a model. Although there has been little study of the maturation of function of the corpus callosum and other forebrain commissures, we do know that these systems are late to myelinate (Yakovlev & Lecours, 1967; Myerson, 1968), and we might infer that the ability to transfer tactile information from one hemisphere to the other changes significantly with age. Therefore, it seemed useful to us to investigate the development of crossed and uncrossed localization on the fingers. We have tested 108 children between 4 years 9 months and 10 years 1 This research was supported in part by Grant NIMH 28456 and Public Health Service Biomedical Research Support Grant RR05755. Requests for reprints should be sent to Dr. David Galin, Langley Porter Neuropsychiatric Institute, University of California at San Francisco, 401 Pamassus Avenue, San Francisco, California 94143. The authors wish to thank California Democratic Assemblyman John Vasconcellos for his encouragement and support of this work. 588 Copyright All riehts
0 1977 by Academic Press. Inc. of retxoduction in anv form reserved.
DEVELOPMENT
OF FINGER TABLE
589
LOCALIZATION
1
TACTILE LOCALIZATION ON THE FINGERS:CROSSEDAND UNCROSSED Age number
4/9”-5111 (n = 16)
6/O-6111 (n = 11)
710-7111 (n = 25)
S/O-8/11 (n = 25)
9/o-9/ 11 (n = 25)
10/o- IO/l I (n = 6)
2.94
1.82
1.08
0.40
0.08
0.17
1.95
1.99
1.38
0.63
0.27
0.37
20.56
13.55
9.08
5.84
4.00
0.67
8.52
9.07
8.82
4.00
2.74
0.75
Total errors Uncrossed Mean Standard deviation Crossed Mean Standard deviation
B First number indicates years; second number indicates months.
month of age, of both sexes, from upper middle class backgrounds. All children with known neurological or behavioral problems were excluded. The child’s hands, palms facing each other, were hidden from his view by a cloth screen, and his eyes were closed. The examiner lightly touched one of ten points on the fingers (proximal, middle, or distal phalanx of each finger, excluding distal index finger and proximal little finger). The child was asked to touch that spot with the thumb of the same hand (‘Irncrossed localization”) or to touch the homologous spot on the opposite hand with the opposite thumb (“crossed localization”). Both finger and joint errors were recorded. There were 40 trials given, 20 for each hand, and 10 each crossed and uncrossed, in counterbalanced orders. We found more crossed than uncrossed errors, for all ages tested, but the difference was strongly age dependent; the younger the child the greater the difference. Even the youngest age group made few uncrossed errors (usually less than five) but averaged over 20 crossed errors. By age 8 or 9 most children made no uncrossed errors and less than six crossed errors. The same pattern of results was seen for the joint errors analyzed alone. These results could be interpreted as showing developmental improvement in interhemispheric transfer of information, perhaps related to progressive myelination or other aspects of maturation of the forebrain commissural neurons. Since the child can perform well on the task in the uncrossed condition it is clear that he understands and can comply with the instructions and meet the motor demands. Other abilities which contribute to tactile localization are known to improve with age, such as appreciation of symmetry or differentiation of body image, but it is difficult to see how they would apply more to crossed than to uncrossed localization. One might suspect that the crossed task offers an opportunity for a left-
590
GALIN, DIAMOND, AND HERRON
right confusion in the order of the fingers; with palms up, on the left hand the middle finger is left of the ring finger, on the right hand the middle finger is right of the ring finger. To reduce this possibility we tested the children with palms facing each other: In this position the fingers of both hands are in the same up-down orientation to each other, eliminating the reversal in left-right orientation. In any case this problem cannot apply to the joint errors, which show the same effect. The interpretation of developmental improvement in interhemispheric information transfer is given some further encouragement by our pilot experiments on crossed and uncrossed object retrieval in children. We have used fabrics of different textures; the child feels a fabric and must retrieve by touch a matching fabric from a container of samples with the same hand or the opposite hand. As with the finger localization task, we find more crossed than uncrossed errors, with the difference greatest in the youngest group. Further research in this area seems warranted. If it is confirmed that maturation of hemispheric interaction is one of the components affecting performance on crossed tactile localization, it still remains to be seen whether this is a relevant component of those “finger localization” tests which predict later cognitive performance. REFERENCES Benton, A. L. 1959. Right-left discrimination pathology. New York: Hoeber-Harper.
and finger
localization:
Development
and
Benton, A. L. 1977a. Neuropsychological significance of finger recognition. In M. Bortner (Ed.), Toward theories of cognitive development, essays in memory of Herbert Birch. In press. Benton, A. L. 1977b. Reflections on the Gerstmann syndrome. Brain and Language, 4, 45-62. Gerstmann, J. 1940. Syndrome of finger agnosia, disorientation for right and left, agraphia and acalculia. Archives of Neurology and Psychiatry, 44, 398-408. Kinsboume, M., & Warrington, E. K. 1963. Developmental factors in reading and writing backwardness. British Journal of Psychology, 15, 132- 137. Lefford, A., Birch, H. G., & Green, G. 1974. The perceptual and cognitive bases for finger localization and selective finger movement in preschool children. Child Development, 45, 335-343. Meyerson, B. A. 1968. Ontogeny of interhemispheric functions. Acta Physiologica Scandinavica, 73, 5- 108. Satz, P., Friel, J., & Rudegair, F. 1974. Differential changes in the acquisition of developmental skills in children who later become dyslexic: A three year follow-up. In D. G. Stein, J. J. Rosen, &N. Butter (Eds.), Plasticity and recovery offunction in the central nervous system. New York: Academic Press. Strub, R., & Geschwind, N. 1974. Gerstmann syndrome without aphasia. Cortex, 10,378387. Yakovlov, P. I., & Lecours, A. 1%7. The myelogenetic cycles of regional maturation of the brain. In A. Minkowski (Ed.), Regional development of the brain in early life. London: Blackwell Scientific Publications.
