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Oral stereognostic differences between apraxics, dysarthrics, aphasics, and normals
JOURNAL
OF COMMUNICATION
DISORDERS
7 (1974), 213-225
ORAL STEREOGNOSTIC DIFFERENCES BETWEEN APRAXICS, DYSARTHRICS, APHASICS, AND NORMALS LOIS A. TEIXEIRA, AND Department
RICHARD
ALAN
H. DEFRAN
C. NICHOLS
of Speech Pathology and Audiology, San Diego State University, San Diego, California 92115
The present study investigates the pattern of errors displayed by the three differentiable groups of neurologically impaired subjects with expressive disorders of speech: aphasics, apraxics and dysarthrics. All exhibit significant oral stereognostic errors, although as has been shown, some disagreement exists as to the significance of errors made by aphasics. All may be encountered in clinical situations, though differentiation between them may present problems.
Introduction Oral stereognostic perception has been recognized as an indicator of nervous system integrity, and in a neurological examination, tests of this function may be included (Forster , 1966). Several studies have compared the oral stereognostic abilities of normal speakers and speakers with speech disorders of manifestly neurological orgins. Class (1956) showed that cerebral palsied (congenital dysarthric) subjects exhibited less accurate form identification than normals, stutterers or speakers with articulation problems. Levin (1965) found that aphasics made three times as many errors on a test of oral form perception as normal speakers, a significant difference (P < O.Ol), although the pattern of form errors was the same for both groups. Guilford and Hawk (1968) found that oral stereognostic scores for apraxics were very poor. Rosenbek (1970), in comparing three groups of neurologically impaired subjects, reported: The apraxia of speech group made significantly (P < O.Ol), more between- and within-class errors on the test of oral form identification than the normal and aphasic control groups, which did not differ significantly from each other. The same conclusions were reached in a further study (Rosenbek, Wertz and Darley , 1973). The contrast with the Levin ( 1965) findings may be noted. Differentiation between these clinical groups in terms of their respective patterns of speech errors [demonstrated in some contexts by Johns and Darley (1970)] and an understanding of the contribution of oral stereognostic perceptual D American Elsevier Publishing
Company,
Inc.,
1974
213
214
LOIS A. TEIXEIRA.
RICHARD H. DEFRAN and ALAN C. NICHOLS
problems to these errors may lead to better therapeutic pathologists.
intervention
by speech
The first hypothesis tested was that the four experimental groups (including a normal control group, apraxics, dysarthrics and aphasics) were drawn from different populations with regard to oral stereognostic perceptions. Further hypotheses, six in all, dealt with pairings between experimental groups as each was compared with the others. For these latter tests (necessarily a posteriori in that they were dependent upon a significant result in the test of the first hypothesis) the hypothesis was similarly that the groups were drawn from different populations. Method Subjects Twenty-six subjects participated in this study. Nine subjects were female and 17 were male. All were between 30 and 70 years of age, providing a mean chronological age of 51.8. Six of the subjects, a control group, were normal in all respects according to screening tests of speech and hearing given by the examiner. Twenty subjects in the present study had been identified by medical personnel as having etiologies of cerebral vascular accidents (CVA). Also, all 20 were reported to have aphasias in the sense that they had apparent speech and language problems. All 20 CVA subjects were previously diagnosed by medical personnel as exhibiting aphasia and apraxia, aphasia and dysarthria, or aphasia without significant articulatory disability. Subjects were chosen from the San Diego State University Speech and Hearing Clinic, San Diego Speech and Hearing Center, Edgemoor Hospital, Newport Language and Speech Center, Palo Alto Veteran’s Hospital and Stanford Hospital. All 20 CVA subjects were given Form B of the Peabody Picture Vocabulary Test (PPVT) (Dunn, 1959) for a general assessment of intelligence and receptive vocabulary. They were also administered a test battery that included the Minnesota Test for Differential Diagnosis of Aphasis (MTDDA) (Schuell, 1968) and a test based upon the results of Johns and Darley (1970), which was used to classify them as apraxic, dysarthric or aphasic. The MTDDA was administered for the present study to all brain-damaged subjects to determine the extent of aphasic involvement. All 20 subjects were found to have significant errors on this test and hence were considered aphasic. Each was classifiable (i.e., all made speech and language errors on the test) in one of Schuell’s groups: Group I-simple aphasia; Group II-aphasia with cerebral involvement of visual process; Group III-aphasia with sensorimotor impairment; Group IV-aphasia with visual and motor involvement; and Group V-irreversible aphasia syndrome (Schuell, 1964). Part Bl of the MTDDA was used to test the visual ability to match forms similar to ones used in the
ORAL
STEREOGNOSTIC
DIFFERENCES
215
present study. One additional CVA patient was not able to match forms visually. He was not included among the subjects for the present study. The procedures for administering the Johns and Darley (1970) test were as follows: Each subject was asked to repeat 60 real or nonsense words. An Arcsin transformation test (Walker and Lev, 1953) was applied to the Johns and Darley (1970) data to determine the phonetic categroies of error in which apraxics and dysarthrics differed. Three categories of error were shown to discriminate between dysarthrics and apraxics: substitutions, distortions and repetitions. (1) A subject was classified as apraxic if his articulator-y errors were predominantly substitutions rather than distortions and if he tended to make a significant number of repetitions. A subject was classified as dysarthric if he tended to make articulatory distortions rather than substitutions and if he tended to make very few repetitions of phonemes (as in verbal blocks). Those braindamaged subjects who made few or no errors at all on the words were classified as aphasic. (2) All those classified as dysarthric by Step (1) made consistent responses for a majority of the words, and the remaining words were performed more poorly. Thus, the dysarthrics demonstrated the predicted dysarthric tendencies and confirmed their classification by the Step (1) procedures. A majority of the test words was produced consistently by the apraxics also. However, they adjusted to correct productions for some of the words (except for one word that was more poorly articulated by one subject) and thus displayed the predicted apraxic tendencies for this task. Thus, the apraxic as well as the dysarthric classifications determined by Step (1) were confirmed by Step (2). (3) A sample of contextual speech was elicited by having each subject read a standard paragraph, “My Grandfather,” at his own rate. He was then urged to read the passage as quickly as possible. When reading the passage more rapidly, those tending to make markedly fewer articulation errors and gaining in overall intelligibility were judged by the investigator to be apraxic. Those performing more poorly to the point of becoming unintelligible were classified by the investigator as dysarthrics. This decision was based upon Johns and Darley’s (1970) observation that dysarthrics tend to become more unintelligible and apraxics tend to become more intelligible while reading faster. Those judged as purely aphasic in the present study tended to articulate similarly to the normal group in that they articulated somewhat more poorly when they increased their speed. Only two apraxics were able to perform this task. However, these two read better when their speech rate was increased. Thus, this step confirmed, in part, classifications established by Steps (1) and (2). Table 1 provides a resume of the data from which the classifications were established. Note that of all subjects participating, eight were classified as aphasic, six as apraxic, six as dysatthric and six as normal. For example, it can be observed that subject No. 1 in the apraxic group made a total of 43 errors on the Johns and Darley (1970) test of repeating 60 words. Of these, 2% were
LOIS A. TEIXEIRA,
216
RICHARD
Descriptive
Subject Age Sex
(1)
54Ml29
(2)
56
F
(3)
32
(4)
PPVT I.Q.
H. DEFRAN
and ALAN
TABLE 1 Data for the Four Experimental Normal Group
MTDDA
No. of
group
errors
Groups a
--- No. 1 Percent of Errors Repetition of!60 words
Repetition 3 times
(I)
(4) (5) (6)
(2)
No. 2
(3)
-
-
30
128
-
-
30
M
112
-
-
30
39
F
125
-
-
30
(5)
55
M
132
-
-
30
(6)
37
F
134
-
-
30
%ource:
C. NICHOLS
No. 3
Reading faster
Slightly worse Slightly worse Slightly worse Slightly worse Slightly worse Slightly worse
Oral stereognostic errors
1
1 2 0 1
1
Johns and Darley (1970) tests.
Apraxic
Subject Age Sex
PPVT I.Q.
MTDDA group
group
- No. 1 Percent of errors No. of Repetition errors of 60 words
___No. 2
No. 3
Repetition 3 times
Reading faster
Oral stereognostic errors
(1) (2) (3) (4) (5) (6)
(1)
52
M
111
II
43
5
25
Better
18
(2)
46
M
60
III
60
100
3
27
12
(3) (4)
53 60
F F
126 87
II III
12 41
100 34
8 66 6
22 24
(5)
45
F
112
III
39
1 92
7 7
23
(6)
70M
61
111
18
78
22 3
26
Could not perform Better Could not perform Could not perform Could not perform
2
61 37
1
10 14 15 10
ORAL
STEREOGNOSTIC Dysarthric
Subject Age Sex
(1) (2) (3) (4) (5) (6)
58 48 48 57 52 54
M M M M M M
PPVT I.Q.
120 73 122 128 107 118
MTDDA group
III IV II II II II
No. of errors
51 29 18 20 23 32
PPVT 1.Q.
MTDDA group
No. of errors
group
- No. 1 Percent of errors Repetition of 60 words
~ No. 2
No. 3
Repetition 3 times
Reading faster
(1) (2) (3)
(4) (5) (6)
85 100 100 90 88 91
Aphasic
Subject Age Sex
9
6
5 4 9
5 8
19 23 28 25 29 28
11 7 2 5 1 2
Worse Worse Worse Worse Worse Worse
Oral stereognostic errors
5 5 8 5 5 2
group
- No. 1 Percent of errors Repetition of 60 words (1) (2) (3) 100
- No. 2
F
73
V
2
(2)
60
M
117
1
0
(3)
67
M
133
II
3
(4)
57
F
118
I
0
30
(5)
49
M
101
11
0
30
(6)
30
M
107
II
0
30
(7)
60
M
127
III
4
(8)
55
F
97
1
0
30
25
Reading faster
(4) (5) (6) 30
52
67
No. 3
Repetition 3 times
(1)
Column 1: distortions; Column 2: substitutions; same; and Column 6: worse.
217
DIFFERENCES
33
75 3
1 29
27 30
Column 3: repetitions;
Could not perform Slightly worse Slightly worse Slightly worse Slightly worse Slightly worse Slightly worse Slightly worse
Oral stereognostic errors
7 8 12 2 3 2 9 1
Column 4: better; Column 5:
218
LOIS A. TEIXEIRA,
RICHARD
H. DEFRAN
and ALAN
C. NICHOLS
distortions, 61% were substitutions and 37% were repetitions. Because his errors were predominantly substitutions and repetitions, he was classified as apraxic. Gn the Johns and Darley (1970) test, repeating 30 words three times in succession, he progressed from incorrect to correct five times and responded with the same pattern 25 times. While reading “My Grandfather,” he articulated more intelligibly when reading faster. The last two results support Step (1) of the Johns and Darley (1970) test classifying him as apraxic according to their criteria. His MTDDA classification was V, and his PPVT 73, which indicated a severe global handicap in language and a depressed receptive vocabulary recognition. The six plastic forms shown in Fig. 1 were selected on the basis of pilot testing and clinical judgments from 20 forms available from the National Institute of Dental Research (NIDR) to measure oral stereognostic ability. These forms were six of the 10 that have been standardized for school children and have been suggested by McDonald and Aungst (1967, pp. 384-390) as yielding diagnostic clues in testing the neurologically impaired. In this task subjects were asked to make 24 oral discriminations. Each of the six forms was presented four times in a random order. While feeling the form orally, the subject was asked to point to one of four shapes on a card in front of him. A different arrangement of forms on a card was presented for each oral discrimination item. The forms drawn on the cards were traced from the plastic forms presented orally. Each subject was given the following instructions (it should be recalled that Bl of the MTDDA had been administered previously): This experiment determines your ability to recognize forms by moving them around in your mouth. While you are feeling the form, I want you to examine this card in front of you and point to the shape which looks like what you feel. The first form will be a demonstration item. You will be allowed to see it after you have matched it. However, you will not be allowed to see any of the other forms either before or after matching them. Do you have any questions? Fine. Let’s begin.
TABLE
2
Number of Oral Stereognostic Each of the Four Experimental Normals 0
1 1 1 1 2
Dysarthrics 2 5 5 5 5 8
Errors Groups
Aphasics
1 2 2 3 I 8 9 12
Apraxics 10 10 12 14 15 18
ORAL
STEREOGNOSTIC
DIFFERENCES
219
n #
c!l
0
0 0
Fig. 1. Demonstration
item, oral stereognostic
forms used.
The “circle-with-a-hole” was selected as a demonstration item because it was usually identified easily by most subjects (McDonald and Aungst, 1967). No subject in this study had difficulty with the “circle-with-a-hole” demonstration item. Results The data are shown in Table 2. The oral stereognostic scores for the subjects in each group and the group means are presented. The apraxics made more oral stereognostic errors than the other three experimental groups. The aphasics and dysarthrics had difficulties with oral form identification but to a lesser degree than apraxics. Out of a possible 24 errors, the mean numbers of errors for the normal group was 1.0, while the mean numbers of errors for the dysarthric and aphasic groups were 5 .O and 5.5, respectively. The greatest number of ‘mean errors, 13.2, was exhibited by the apraxic group, and their range was between 10 and 18 errors. The aphasic group’s scores were split. Half made three errors or less while the other half made between 7 and 12 errors. Although the dysartbric group’s mean number of errors was similar to the aphasics’, the scores were less varied, ranging from two to eight errors. The analysis of the data was conducted according to two designs described by Siegel (1956). The fist design, the Kruskal-Wallis One-Way Analysis of Variance (Siegel, 1956, pp, 184-194) was used to determine whether the four independent groups in the study were from different populations. The second design employed was the Mann-Whitney U Test (Siegel, 1956, pp. 116-117), which permitted a set of tests to determine whether any given pair of the experimental groups differed from each other in the ability to discriminate forms orally*
220
LOIS A. TEIXEIRA.
RICHARD
H. DEFRAN TABLE
and ALAN
C. NICHOLS
3
Group Means and Differences Between the Means (for the Four Experimental Groups) and the Mann-Whitney U Values from Tests of the Differences Between the Means (a = 0.05)
Aphasics Groups
N
Mean
Difference
Apraxics Aphasics Dysartbrics Normals
6 8 6 6
13.2 5.5 5.0 1.0
7.70
Comparison Apraxics vs. normals Apraxics vs. dysarthrics Normals vs. aphasics Apraxics vs. aphasics Normals vs. dysarthrics Apraxics vs. dysarthrics
r 4 3 3 2 2 2
2.50 a
Required probability for Significance x’ 0.009 0.013 0.013 0.025 0.025 0.025
Normals
Dysarthrics U
Difference
U
Difference
8.20 0.50
0.0” 23.50
12.20 4.50 4.0
U or U’
Obtained probability
0.0 0.0 4.0 2.50 0.5 23.50
0.002 0.002 0.008 0.004 0.004 1.050
U 0.0 a 4.0 a 0.5 (1
Decision Reject HO Reject HO Reject HO Reject Ho Reject Ho Do not reject HO
’ P < 0.05 taking into account Ryan’s procedure (see Kirk, 1968) for a posteriori tests using the method of adjusted significance levels as shown above.
The Kruskal-Wallis Test resulted in a statistic (H = 18.2, G!! = 3) that was significant beyond the 0.001 level of confidence. Thus, it was possible to reject the null hypothesis and accept the hypothesis that the groups came from different populations. The Mann-Whitney U Test was used to test for differences between the possible pairs from among the four experimental groups to determine whether the two groups of a given pairing were indeed from different populations with regard to oral stereognostic ability. The level of rejection was set at 0.05. Table 3 presents results of group means and differences between groups. The Mann-Whitney U values from tests of the differences between the means summarize the analyses. Ryan’s procedures (see Table 3) of adjusting significance levels for multiple comparisons of experimental groups by the Mann-Whitney U were reported by Kirk (1968). These procedures were applied to results of the Mann-Whitney U Tests to avoid the risk of spuriously rejecting the null hypothesis for one of several comparisons. It may be noted in Table 3 that the apraxics and aphasics showed a mean difference in oral stereognosis of 7.70. A Mann-Whitney U of 2.50 demon-
ORAL
STEREOGNOSTIC
strated that this was a significant
difference
DIFFERENCES
in oral stereognostic
221
scores beyond
the 0.05 level of confidence (adjusted). That is, apraxics do more poorly than aphasics when discriminating forms orally.; For apraxics and dysarthrics, there was a mean difference of 8.20 with a Mann-Whitney U of 0. Therefore, this difference was also significant beyond the 0.05 level of confidence (adjusted). This indicated that apraxics had significantly lower scores on oral form discrimination tasks than dysarthrics. A Mann-Whitney U of 0.5 and a mean difference of 4.0 between thedysarthrics and normal groups revealed a significant difference in oral stereognostic errors beyond the 0.05 level (adjusted). That is, the normal group showed a significantly better score than the dysarthrics. Of all the null hypotheses tested, there was only one which could not be rejected at the 0.05 level of confidence, i.e., aphasics and dysarthrics could not be shown to differ significantly by this statistical test.
Discussion Table 3 shows that the normals scored higher on the oral stereognostic test than any of the clinical groups, while the apraxics scored significantly lower in comparison to the normals, aphasics and dysarthrics. According to one group of theorists (Wepman et al., 1960), apraxia may be defined as a “modalitybound, non-symbolic transmissive (output) disorder.” They did discuss the importance of external and internal feedback of language to the comprehension, integration and use of language. However, their description of apraxia specified a disorder independent of any feedback (input) dysfunction. The results of the present study appeared to show that apraxics do have oral receptive difficulties, however. Thus, the apraxic appears not only to have motor output speech difficulties but input difficulties as well. Other empirical studies have found results similar to those in the present experiment. Rosenbek (1970; see also Rosenbek, Wertz and Darley, 1973) found that persons with apraxia have significant oral sensory-perceptual deficit. It was concluded that apraxia involves a significant sensory deficit. The present study extends the conclusion to include sensory deficits among dysarthrics as well. Rosenbek (1970) used operational definitions of apraxia and aphasia to define the experimental groups, as did the present experimenters. The range in the experimental groups was similar to the present study, although the etiologies included trauma and postsurgical symptoms as well as cerebral vascular accidents (Rosenbek, 1970; Rosenbek, Wertz and Darley, 1973). The present study included only patients with medically verified records of cerebral vascular accidents. In the present study stubjects were required to match visual input with stereognostic input. A criticism by Weinberg (1970, p. 346) was that such a method, involving as it does intersensory matching (using the visual sensory modality), does not permit a “pure” measure of oral sensory capacity. That is
222
LOIS A. TEIXEIRA,
RICHARD
H. DEFRAN and ALAN C. NICHOLS
to say, the methodology of the present study inevitably produced ambiguous information regarding oral tactile perception. This consideration influenced Rosenbek (1970) to require that each subject report whether pairs of forms presented one at a time were the “same” or “different” (a discrimination test pro cedure). However, it should be noted that one condition of the present study was that the subjects be capable of performing without error on the Bl subtest of the MTDDA. That is, they demonstrated that they did not have difficulty with the visual-matching modality. If a client has visual-matching difficulties (as shown by a test such as the B 1)) some cross-modality free procedure in scoring and interpretation should be unquestionably used. Otherwise, the visualmatching method provides advantages and may prove in practice to be the procedure-of-choice, e.g., the matching (pointing) response does not involve evoked language as does a “same-different” judgment and may thus involve a lower chance of linguistically bound error. Moreover, the subjects chose from one of four possible responses, while the discrimination judgments involved one of two possible responses. The suggestion that cross-modality matching may have advantages is also supported by the fact that both studies demonstrated similar results. That is to say, the method of visually matching forms to oral sensory inputs revealed the same sensory-perceptual difficulties in apraxics as did the discrimination procedure, even though Rosenbek (1970) took care to avoid cross-modality input. In another study (Levin, 1965), 27 normal and 27 aphasics were compared for oral stereognostic perceptions. Her method of testing oral stereognostic ability was similar to that used in the present study. Each subject was asked to point to the tracing on paper that corresponded to the form in his mouth. The aphasics made three times as many errors as normals. This is a smaller ratio (3: 1) than that demonstrated in the present study (5.5: 1). However, her results were reported in terms of the total number of group errors for each form, which makes further comparison with the present experiment difficult. Her results, however, suggest that methodology may have something to do with the failure of the within-modality discrimination studies’to demonstrate differences between aphasics and normals. Guilford and Hawk (1968) compared 13 normal and 13 aphasic subjects on tests of visual, digital-tactile and oral stereognostic abilities. They used 14 plastic forms and required their subjects to match forms manipulated orally to a visual display. They reported that the oral apraxics had very poor scores on oral stereognostic tests. Unfortunately, similar findings by Rosenbek (1970) and the present experiment cannot be meaningfully compared to Guilford and Hawk’s (1968) results, for the latter researchers did not report any statistical summary or treatment of the oral apraxic group performance. In the present study no significant difference was found between the dysarthrics and the aphasics in oral stereognostic ability. This may be explained in part by the bimodal distribution of the aphasics’ oral stereognostic scores. Table
ORAL
STEREOGNOSTIC
DIFFERENCES
223
2 shows that four of the aphasics scored low in errors (1, 2, 2, 3) and four scored relatively high (7, 8, 9, 12). That is, half scored as did the normals, and the other half scored more like the apraxics. The dysarthrics’ scores (2, 5, 5, 5, 5, 8) fell midway between these two aphasic groups with little overlap. By referring to the aphasic group’s MTDDA scores it can be shown (see Table 1) that those scoring like normals were all within Schuell’s (1%4) classifications of Group I or II. This was also true of two of the aphasics in the higherror modal group. However, two of the aphasics scoring like apraxics were classified in Group III and V, respectively. In his study of apraxics, Rosenbek (1970, p. 117; see also Rosenbek, Wertz and Darley, 1973, p. 32) found that severity of apraxia and oral-sensory difficulties are interdependent and that severe apraxia and severe oral-sensory deficits coexist. They also found a lack of homogeneity in the apraxic group, which appeared related to severity of apraxic symptoms. They also showed that apraxics and aphasics differed significantly in this dimension. By analogy, it is possible that the severity dimension in the aphasic population contributed to a bimodal distribution. Further study with more subjects is needed to test his hypotheses, particularly since Rosenbek, Wertz and Darley (1973) found a similar separation among their apraxics, which they also attributed to the severity dimension. During the editorial review of this paper, the possibility was raised that “a motor rather than sensory defect in the apraxics” could account for the findings for this group. This observation has substantial merit, and indeed, raises the methodological question of the contribution of the subjects’ manipulative behaviors (moving the test form around on the tongue) to oral stereognostic measurements. Controlled studies are needed relative to the manipulative variable with all client populations where application of oral stereognostic testing is anticipated. The four groups represented in the subject populations of the present study should be included in such investigations. Clinical Implications The results of the present study suggest that there is a sensory-perceptual deficit in apraxics and to a lesser degree in dysarthrics and aphasics. If this is so, articulation therapy with such clients may be directed toward heightening responsiveness to the patterns of auditory, proprioceptive and tactile sensations associated with the overlapping, ballistic movements of articulation (McDonald, 1964). Johns (1%8) further recommended providing auditory and visual cues to correct phoneme production while simultaneously teaching the patient to focus on auditory, visual and tactile-kinesthetic feedback provided by his own speech attempts. However, as Rosenbek (1970) stated: . urging the aphasic patient to attend the tactile-kinesthetic cues may be an uneconomical and frustrating experience for both clinician and client, especially if the patient suffers from extreme sensory deficit (Rosenbek, 1970, p. 108).
224
LOIS A. TEXEIRA,
RICHARD
H. DEFRAN
and ALAN
C. NICHOLS
He felt that a wiser procedure might be to proceed with a multisensory approach only insofar as visual, auditory and oral sensory-perceptual integrity is proserved as a system. If any modality is not intact, he suggested either (1) directing therapy only through intact input modalities or (2) using residual tactilekinesthetic ability during both verbal and nonverbal oral activities to try to determine whether gains in both sensory processing and speech production occur. The present study suggests the second alternative is feasible. That is, none of the apraxics scored 24 errors; all had some residual ability; 45% was the average. Preliminary work with several apraxic clients in our clinic has shown that they can improve in oral stereognostic discriminations. This was also a finding in the Wilhelm (1970) study with children as subjects. Our practice has been to employ alternate-discrimination and articulation-improvement procedures in therapy. Sensory focus upon articulators critical to the target phonemes is attempted during discrimination work, and the articulatory practice involves a multiple feedback model in which morphemes and longer utterances are attempted with the client’s intent directed toward the integration of feedback loops and linguistic content. The work has not been extensive enough to permit analysis. Clinical satisfaction has been expressed by clients and clinicians. The present article is based upon an M.A. thesis completed in 1972 by Lois A. Teixeira at California State University, San Diego, under the direction of the second and third authors. References Class, L.W. A comparative study of normal speakers and speech defectives with regard to the tactual-kinesthetic perception of form with the tongue. Masters thesis, The Ohio State University, 1956. Dunn, L.M. Peabody Picrure Vocabulary Test(Form B). Circle Pines, Minn.: American Guidance Service, Inc., 1959. Forster, F.M. Synopsis ofNeurology. Saint Louis: The C.V. Mosby Co., 1966. Guilford, A.M. & Hawk, A.M. A comparative study of form identification in neurologically impaired and normal adult subjects. Speech and Hearing Science Research Reports. University of Michigan, pp. 1-9, 1968. Johns, D.F. A systematic study of phonemic variability in apraxia of speech. Doctoral dissertation, Florida State University, 1968. Johns, D.F., & Darley, F.L. Phonemic variability in apraxia of speech. J. Speech Hearing Res., 1970, 13, 556-583. Kirk, R.E. Experimental Design: Procedures for rhe Behavioral Sciences. Belmont, Calif.: Wadsworth, 1968, pp. 494-498. Levin, S.I. A study of performance of normal subjects and aphasic subjects in tests of oral and manual stereognosis. Master’s thesis, The Ohio State University, 1965. McDonald, E. Articulation Testing and Treatment-A Sensory-Motor Approach. Pittsburgh: Stanwix House, 1964. McDonald, E.T., & Aungst, L.F. An abbreviated test of oral stereognosis. In J.F. Bosma (Ed.),
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Second Symposium on Oral Sensation and Perception. Springfield, Ill.: Charles C Thomas, 1970, pp. 384-390. Rosenbek, J.C. Oral sensation and perception in apraxia of speech and aphasia. Doctoral Dissertation, University of Colorado, 1970. Rosenbek, J.C., Wertz, R.T., & Dariey, R.L. Oral sensation and perception in apraxia of speech and aphasia. J. Speech Hearing Res., 1973, 16, 22-36. Schuell, H. Classification of aphasic patients. Aphasia in Adults. New York: Harper and Row, 1964. Schuell, H. Minnesota Tesf for Differential Diagnosis of Aphasia. Minneapolis: University of Minnesota Press, 1968. Siegel, S. Nonparametric Statistics for the Behavioral Sciences. New York: McGraw-Hill, 1956. Walker, H.M. & Lev, J. Statistical Inference. New York: Henry Holt and Co., 1953, pp. 423-425. Weinberg, B., Liss G.M., & Hillis, J. A comparative study of visual, manual, and oral form identification in speech impaired and normal speaking children. In J. F. Bosma (Ed.), Second Symposium on Oral Sensation and Perceprion. Springfield, Ill.: Charles C Thomas, 1970, pp. 350-356. Wepman, J.M., Jones, L.V., Bock, R.D., & Van Pelt, D. Studies in aphasia: Background and theoretical implication. J. Speech Hearing Dis., 1960, 323-332. Wilhelm, C.L. The effects of oral form recognition training on articulation in children.Doctoral dissertation, University of Kansas, 1970.
OF COMMUNICATION
DISORDERS
7 (1974), 213-225
ORAL STEREOGNOSTIC DIFFERENCES BETWEEN APRAXICS, DYSARTHRICS, APHASICS, AND NORMALS LOIS A. TEIXEIRA, AND Department
RICHARD
ALAN
H. DEFRAN
C. NICHOLS
of Speech Pathology and Audiology, San Diego State University, San Diego, California 92115
The present study investigates the pattern of errors displayed by the three differentiable groups of neurologically impaired subjects with expressive disorders of speech: aphasics, apraxics and dysarthrics. All exhibit significant oral stereognostic errors, although as has been shown, some disagreement exists as to the significance of errors made by aphasics. All may be encountered in clinical situations, though differentiation between them may present problems.
Introduction Oral stereognostic perception has been recognized as an indicator of nervous system integrity, and in a neurological examination, tests of this function may be included (Forster , 1966). Several studies have compared the oral stereognostic abilities of normal speakers and speakers with speech disorders of manifestly neurological orgins. Class (1956) showed that cerebral palsied (congenital dysarthric) subjects exhibited less accurate form identification than normals, stutterers or speakers with articulation problems. Levin (1965) found that aphasics made three times as many errors on a test of oral form perception as normal speakers, a significant difference (P < O.Ol), although the pattern of form errors was the same for both groups. Guilford and Hawk (1968) found that oral stereognostic scores for apraxics were very poor. Rosenbek (1970), in comparing three groups of neurologically impaired subjects, reported: The apraxia of speech group made significantly (P < O.Ol), more between- and within-class errors on the test of oral form identification than the normal and aphasic control groups, which did not differ significantly from each other. The same conclusions were reached in a further study (Rosenbek, Wertz and Darley , 1973). The contrast with the Levin ( 1965) findings may be noted. Differentiation between these clinical groups in terms of their respective patterns of speech errors [demonstrated in some contexts by Johns and Darley (1970)] and an understanding of the contribution of oral stereognostic perceptual D American Elsevier Publishing
Company,
Inc.,
1974
213
214
LOIS A. TEIXEIRA.
RICHARD H. DEFRAN and ALAN C. NICHOLS
problems to these errors may lead to better therapeutic pathologists.
intervention
by speech
The first hypothesis tested was that the four experimental groups (including a normal control group, apraxics, dysarthrics and aphasics) were drawn from different populations with regard to oral stereognostic perceptions. Further hypotheses, six in all, dealt with pairings between experimental groups as each was compared with the others. For these latter tests (necessarily a posteriori in that they were dependent upon a significant result in the test of the first hypothesis) the hypothesis was similarly that the groups were drawn from different populations. Method Subjects Twenty-six subjects participated in this study. Nine subjects were female and 17 were male. All were between 30 and 70 years of age, providing a mean chronological age of 51.8. Six of the subjects, a control group, were normal in all respects according to screening tests of speech and hearing given by the examiner. Twenty subjects in the present study had been identified by medical personnel as having etiologies of cerebral vascular accidents (CVA). Also, all 20 were reported to have aphasias in the sense that they had apparent speech and language problems. All 20 CVA subjects were previously diagnosed by medical personnel as exhibiting aphasia and apraxia, aphasia and dysarthria, or aphasia without significant articulatory disability. Subjects were chosen from the San Diego State University Speech and Hearing Clinic, San Diego Speech and Hearing Center, Edgemoor Hospital, Newport Language and Speech Center, Palo Alto Veteran’s Hospital and Stanford Hospital. All 20 CVA subjects were given Form B of the Peabody Picture Vocabulary Test (PPVT) (Dunn, 1959) for a general assessment of intelligence and receptive vocabulary. They were also administered a test battery that included the Minnesota Test for Differential Diagnosis of Aphasis (MTDDA) (Schuell, 1968) and a test based upon the results of Johns and Darley (1970), which was used to classify them as apraxic, dysarthric or aphasic. The MTDDA was administered for the present study to all brain-damaged subjects to determine the extent of aphasic involvement. All 20 subjects were found to have significant errors on this test and hence were considered aphasic. Each was classifiable (i.e., all made speech and language errors on the test) in one of Schuell’s groups: Group I-simple aphasia; Group II-aphasia with cerebral involvement of visual process; Group III-aphasia with sensorimotor impairment; Group IV-aphasia with visual and motor involvement; and Group V-irreversible aphasia syndrome (Schuell, 1964). Part Bl of the MTDDA was used to test the visual ability to match forms similar to ones used in the
ORAL
STEREOGNOSTIC
DIFFERENCES
215
present study. One additional CVA patient was not able to match forms visually. He was not included among the subjects for the present study. The procedures for administering the Johns and Darley (1970) test were as follows: Each subject was asked to repeat 60 real or nonsense words. An Arcsin transformation test (Walker and Lev, 1953) was applied to the Johns and Darley (1970) data to determine the phonetic categroies of error in which apraxics and dysarthrics differed. Three categories of error were shown to discriminate between dysarthrics and apraxics: substitutions, distortions and repetitions. (1) A subject was classified as apraxic if his articulator-y errors were predominantly substitutions rather than distortions and if he tended to make a significant number of repetitions. A subject was classified as dysarthric if he tended to make articulatory distortions rather than substitutions and if he tended to make very few repetitions of phonemes (as in verbal blocks). Those braindamaged subjects who made few or no errors at all on the words were classified as aphasic. (2) All those classified as dysarthric by Step (1) made consistent responses for a majority of the words, and the remaining words were performed more poorly. Thus, the dysarthrics demonstrated the predicted dysarthric tendencies and confirmed their classification by the Step (1) procedures. A majority of the test words was produced consistently by the apraxics also. However, they adjusted to correct productions for some of the words (except for one word that was more poorly articulated by one subject) and thus displayed the predicted apraxic tendencies for this task. Thus, the apraxic as well as the dysarthric classifications determined by Step (1) were confirmed by Step (2). (3) A sample of contextual speech was elicited by having each subject read a standard paragraph, “My Grandfather,” at his own rate. He was then urged to read the passage as quickly as possible. When reading the passage more rapidly, those tending to make markedly fewer articulation errors and gaining in overall intelligibility were judged by the investigator to be apraxic. Those performing more poorly to the point of becoming unintelligible were classified by the investigator as dysarthrics. This decision was based upon Johns and Darley’s (1970) observation that dysarthrics tend to become more unintelligible and apraxics tend to become more intelligible while reading faster. Those judged as purely aphasic in the present study tended to articulate similarly to the normal group in that they articulated somewhat more poorly when they increased their speed. Only two apraxics were able to perform this task. However, these two read better when their speech rate was increased. Thus, this step confirmed, in part, classifications established by Steps (1) and (2). Table 1 provides a resume of the data from which the classifications were established. Note that of all subjects participating, eight were classified as aphasic, six as apraxic, six as dysatthric and six as normal. For example, it can be observed that subject No. 1 in the apraxic group made a total of 43 errors on the Johns and Darley (1970) test of repeating 60 words. Of these, 2% were
LOIS A. TEIXEIRA,
216
RICHARD
Descriptive
Subject Age Sex
(1)
54Ml29
(2)
56
F
(3)
32
(4)
PPVT I.Q.
H. DEFRAN
and ALAN
TABLE 1 Data for the Four Experimental Normal Group
MTDDA
No. of
group
errors
Groups a
--- No. 1 Percent of Errors Repetition of!60 words
Repetition 3 times
(I)
(4) (5) (6)
(2)
No. 2
(3)
-
-
30
128
-
-
30
M
112
-
-
30
39
F
125
-
-
30
(5)
55
M
132
-
-
30
(6)
37
F
134
-
-
30
%ource:
C. NICHOLS
No. 3
Reading faster
Slightly worse Slightly worse Slightly worse Slightly worse Slightly worse Slightly worse
Oral stereognostic errors
1
1 2 0 1
1
Johns and Darley (1970) tests.
Apraxic
Subject Age Sex
PPVT I.Q.
MTDDA group
group
- No. 1 Percent of errors No. of Repetition errors of 60 words
___No. 2
No. 3
Repetition 3 times
Reading faster
Oral stereognostic errors
(1) (2) (3) (4) (5) (6)
(1)
52
M
111
II
43
5
25
Better
18
(2)
46
M
60
III
60
100
3
27
12
(3) (4)
53 60
F F
126 87
II III
12 41
100 34
8 66 6
22 24
(5)
45
F
112
III
39
1 92
7 7
23
(6)
70M
61
111
18
78
22 3
26
Could not perform Better Could not perform Could not perform Could not perform
2
61 37
1
10 14 15 10
ORAL
STEREOGNOSTIC Dysarthric
Subject Age Sex
(1) (2) (3) (4) (5) (6)
58 48 48 57 52 54
M M M M M M
PPVT I.Q.
120 73 122 128 107 118
MTDDA group
III IV II II II II
No. of errors
51 29 18 20 23 32
PPVT 1.Q.
MTDDA group
No. of errors
group
- No. 1 Percent of errors Repetition of 60 words
~ No. 2
No. 3
Repetition 3 times
Reading faster
(1) (2) (3)
(4) (5) (6)
85 100 100 90 88 91
Aphasic
Subject Age Sex
9
6
5 4 9
5 8
19 23 28 25 29 28
11 7 2 5 1 2
Worse Worse Worse Worse Worse Worse
Oral stereognostic errors
5 5 8 5 5 2
group
- No. 1 Percent of errors Repetition of 60 words (1) (2) (3) 100
- No. 2
F
73
V
2
(2)
60
M
117
1
0
(3)
67
M
133
II
3
(4)
57
F
118
I
0
30
(5)
49
M
101
11
0
30
(6)
30
M
107
II
0
30
(7)
60
M
127
III
4
(8)
55
F
97
1
0
30
25
Reading faster
(4) (5) (6) 30
52
67
No. 3
Repetition 3 times
(1)
Column 1: distortions; Column 2: substitutions; same; and Column 6: worse.
217
DIFFERENCES
33
75 3
1 29
27 30
Column 3: repetitions;
Could not perform Slightly worse Slightly worse Slightly worse Slightly worse Slightly worse Slightly worse Slightly worse
Oral stereognostic errors
7 8 12 2 3 2 9 1
Column 4: better; Column 5:
218
LOIS A. TEIXEIRA,
RICHARD
H. DEFRAN
and ALAN
C. NICHOLS
distortions, 61% were substitutions and 37% were repetitions. Because his errors were predominantly substitutions and repetitions, he was classified as apraxic. Gn the Johns and Darley (1970) test, repeating 30 words three times in succession, he progressed from incorrect to correct five times and responded with the same pattern 25 times. While reading “My Grandfather,” he articulated more intelligibly when reading faster. The last two results support Step (1) of the Johns and Darley (1970) test classifying him as apraxic according to their criteria. His MTDDA classification was V, and his PPVT 73, which indicated a severe global handicap in language and a depressed receptive vocabulary recognition. The six plastic forms shown in Fig. 1 were selected on the basis of pilot testing and clinical judgments from 20 forms available from the National Institute of Dental Research (NIDR) to measure oral stereognostic ability. These forms were six of the 10 that have been standardized for school children and have been suggested by McDonald and Aungst (1967, pp. 384-390) as yielding diagnostic clues in testing the neurologically impaired. In this task subjects were asked to make 24 oral discriminations. Each of the six forms was presented four times in a random order. While feeling the form orally, the subject was asked to point to one of four shapes on a card in front of him. A different arrangement of forms on a card was presented for each oral discrimination item. The forms drawn on the cards were traced from the plastic forms presented orally. Each subject was given the following instructions (it should be recalled that Bl of the MTDDA had been administered previously): This experiment determines your ability to recognize forms by moving them around in your mouth. While you are feeling the form, I want you to examine this card in front of you and point to the shape which looks like what you feel. The first form will be a demonstration item. You will be allowed to see it after you have matched it. However, you will not be allowed to see any of the other forms either before or after matching them. Do you have any questions? Fine. Let’s begin.
TABLE
2
Number of Oral Stereognostic Each of the Four Experimental Normals 0
1 1 1 1 2
Dysarthrics 2 5 5 5 5 8
Errors Groups
Aphasics
1 2 2 3 I 8 9 12
Apraxics 10 10 12 14 15 18
ORAL
STEREOGNOSTIC
DIFFERENCES
219
n #
c!l
0
0 0
Fig. 1. Demonstration
item, oral stereognostic
forms used.
The “circle-with-a-hole” was selected as a demonstration item because it was usually identified easily by most subjects (McDonald and Aungst, 1967). No subject in this study had difficulty with the “circle-with-a-hole” demonstration item. Results The data are shown in Table 2. The oral stereognostic scores for the subjects in each group and the group means are presented. The apraxics made more oral stereognostic errors than the other three experimental groups. The aphasics and dysarthrics had difficulties with oral form identification but to a lesser degree than apraxics. Out of a possible 24 errors, the mean numbers of errors for the normal group was 1.0, while the mean numbers of errors for the dysarthric and aphasic groups were 5 .O and 5.5, respectively. The greatest number of ‘mean errors, 13.2, was exhibited by the apraxic group, and their range was between 10 and 18 errors. The aphasic group’s scores were split. Half made three errors or less while the other half made between 7 and 12 errors. Although the dysartbric group’s mean number of errors was similar to the aphasics’, the scores were less varied, ranging from two to eight errors. The analysis of the data was conducted according to two designs described by Siegel (1956). The fist design, the Kruskal-Wallis One-Way Analysis of Variance (Siegel, 1956, pp, 184-194) was used to determine whether the four independent groups in the study were from different populations. The second design employed was the Mann-Whitney U Test (Siegel, 1956, pp. 116-117), which permitted a set of tests to determine whether any given pair of the experimental groups differed from each other in the ability to discriminate forms orally*
220
LOIS A. TEIXEIRA.
RICHARD
H. DEFRAN TABLE
and ALAN
C. NICHOLS
3
Group Means and Differences Between the Means (for the Four Experimental Groups) and the Mann-Whitney U Values from Tests of the Differences Between the Means (a = 0.05)
Aphasics Groups
N
Mean
Difference
Apraxics Aphasics Dysartbrics Normals
6 8 6 6
13.2 5.5 5.0 1.0
7.70
Comparison Apraxics vs. normals Apraxics vs. dysarthrics Normals vs. aphasics Apraxics vs. aphasics Normals vs. dysarthrics Apraxics vs. dysarthrics
r 4 3 3 2 2 2
2.50 a
Required probability for Significance x’ 0.009 0.013 0.013 0.025 0.025 0.025
Normals
Dysarthrics U
Difference
U
Difference
8.20 0.50
0.0” 23.50
12.20 4.50 4.0
U or U’
Obtained probability
0.0 0.0 4.0 2.50 0.5 23.50
0.002 0.002 0.008 0.004 0.004 1.050
U 0.0 a 4.0 a 0.5 (1
Decision Reject HO Reject HO Reject HO Reject Ho Reject Ho Do not reject HO
’ P < 0.05 taking into account Ryan’s procedure (see Kirk, 1968) for a posteriori tests using the method of adjusted significance levels as shown above.
The Kruskal-Wallis Test resulted in a statistic (H = 18.2, G!! = 3) that was significant beyond the 0.001 level of confidence. Thus, it was possible to reject the null hypothesis and accept the hypothesis that the groups came from different populations. The Mann-Whitney U Test was used to test for differences between the possible pairs from among the four experimental groups to determine whether the two groups of a given pairing were indeed from different populations with regard to oral stereognostic ability. The level of rejection was set at 0.05. Table 3 presents results of group means and differences between groups. The Mann-Whitney U values from tests of the differences between the means summarize the analyses. Ryan’s procedures (see Table 3) of adjusting significance levels for multiple comparisons of experimental groups by the Mann-Whitney U were reported by Kirk (1968). These procedures were applied to results of the Mann-Whitney U Tests to avoid the risk of spuriously rejecting the null hypothesis for one of several comparisons. It may be noted in Table 3 that the apraxics and aphasics showed a mean difference in oral stereognosis of 7.70. A Mann-Whitney U of 2.50 demon-
ORAL
STEREOGNOSTIC
strated that this was a significant
difference
DIFFERENCES
in oral stereognostic
221
scores beyond
the 0.05 level of confidence (adjusted). That is, apraxics do more poorly than aphasics when discriminating forms orally.; For apraxics and dysarthrics, there was a mean difference of 8.20 with a Mann-Whitney U of 0. Therefore, this difference was also significant beyond the 0.05 level of confidence (adjusted). This indicated that apraxics had significantly lower scores on oral form discrimination tasks than dysarthrics. A Mann-Whitney U of 0.5 and a mean difference of 4.0 between thedysarthrics and normal groups revealed a significant difference in oral stereognostic errors beyond the 0.05 level (adjusted). That is, the normal group showed a significantly better score than the dysarthrics. Of all the null hypotheses tested, there was only one which could not be rejected at the 0.05 level of confidence, i.e., aphasics and dysarthrics could not be shown to differ significantly by this statistical test.
Discussion Table 3 shows that the normals scored higher on the oral stereognostic test than any of the clinical groups, while the apraxics scored significantly lower in comparison to the normals, aphasics and dysarthrics. According to one group of theorists (Wepman et al., 1960), apraxia may be defined as a “modalitybound, non-symbolic transmissive (output) disorder.” They did discuss the importance of external and internal feedback of language to the comprehension, integration and use of language. However, their description of apraxia specified a disorder independent of any feedback (input) dysfunction. The results of the present study appeared to show that apraxics do have oral receptive difficulties, however. Thus, the apraxic appears not only to have motor output speech difficulties but input difficulties as well. Other empirical studies have found results similar to those in the present experiment. Rosenbek (1970; see also Rosenbek, Wertz and Darley, 1973) found that persons with apraxia have significant oral sensory-perceptual deficit. It was concluded that apraxia involves a significant sensory deficit. The present study extends the conclusion to include sensory deficits among dysarthrics as well. Rosenbek (1970) used operational definitions of apraxia and aphasia to define the experimental groups, as did the present experimenters. The range in the experimental groups was similar to the present study, although the etiologies included trauma and postsurgical symptoms as well as cerebral vascular accidents (Rosenbek, 1970; Rosenbek, Wertz and Darley, 1973). The present study included only patients with medically verified records of cerebral vascular accidents. In the present study stubjects were required to match visual input with stereognostic input. A criticism by Weinberg (1970, p. 346) was that such a method, involving as it does intersensory matching (using the visual sensory modality), does not permit a “pure” measure of oral sensory capacity. That is
222
LOIS A. TEIXEIRA,
RICHARD
H. DEFRAN and ALAN C. NICHOLS
to say, the methodology of the present study inevitably produced ambiguous information regarding oral tactile perception. This consideration influenced Rosenbek (1970) to require that each subject report whether pairs of forms presented one at a time were the “same” or “different” (a discrimination test pro cedure). However, it should be noted that one condition of the present study was that the subjects be capable of performing without error on the Bl subtest of the MTDDA. That is, they demonstrated that they did not have difficulty with the visual-matching modality. If a client has visual-matching difficulties (as shown by a test such as the B 1)) some cross-modality free procedure in scoring and interpretation should be unquestionably used. Otherwise, the visualmatching method provides advantages and may prove in practice to be the procedure-of-choice, e.g., the matching (pointing) response does not involve evoked language as does a “same-different” judgment and may thus involve a lower chance of linguistically bound error. Moreover, the subjects chose from one of four possible responses, while the discrimination judgments involved one of two possible responses. The suggestion that cross-modality matching may have advantages is also supported by the fact that both studies demonstrated similar results. That is to say, the method of visually matching forms to oral sensory inputs revealed the same sensory-perceptual difficulties in apraxics as did the discrimination procedure, even though Rosenbek (1970) took care to avoid cross-modality input. In another study (Levin, 1965), 27 normal and 27 aphasics were compared for oral stereognostic perceptions. Her method of testing oral stereognostic ability was similar to that used in the present study. Each subject was asked to point to the tracing on paper that corresponded to the form in his mouth. The aphasics made three times as many errors as normals. This is a smaller ratio (3: 1) than that demonstrated in the present study (5.5: 1). However, her results were reported in terms of the total number of group errors for each form, which makes further comparison with the present experiment difficult. Her results, however, suggest that methodology may have something to do with the failure of the within-modality discrimination studies’to demonstrate differences between aphasics and normals. Guilford and Hawk (1968) compared 13 normal and 13 aphasic subjects on tests of visual, digital-tactile and oral stereognostic abilities. They used 14 plastic forms and required their subjects to match forms manipulated orally to a visual display. They reported that the oral apraxics had very poor scores on oral stereognostic tests. Unfortunately, similar findings by Rosenbek (1970) and the present experiment cannot be meaningfully compared to Guilford and Hawk’s (1968) results, for the latter researchers did not report any statistical summary or treatment of the oral apraxic group performance. In the present study no significant difference was found between the dysarthrics and the aphasics in oral stereognostic ability. This may be explained in part by the bimodal distribution of the aphasics’ oral stereognostic scores. Table
ORAL
STEREOGNOSTIC
DIFFERENCES
223
2 shows that four of the aphasics scored low in errors (1, 2, 2, 3) and four scored relatively high (7, 8, 9, 12). That is, half scored as did the normals, and the other half scored more like the apraxics. The dysarthrics’ scores (2, 5, 5, 5, 5, 8) fell midway between these two aphasic groups with little overlap. By referring to the aphasic group’s MTDDA scores it can be shown (see Table 1) that those scoring like normals were all within Schuell’s (1%4) classifications of Group I or II. This was also true of two of the aphasics in the higherror modal group. However, two of the aphasics scoring like apraxics were classified in Group III and V, respectively. In his study of apraxics, Rosenbek (1970, p. 117; see also Rosenbek, Wertz and Darley, 1973, p. 32) found that severity of apraxia and oral-sensory difficulties are interdependent and that severe apraxia and severe oral-sensory deficits coexist. They also found a lack of homogeneity in the apraxic group, which appeared related to severity of apraxic symptoms. They also showed that apraxics and aphasics differed significantly in this dimension. By analogy, it is possible that the severity dimension in the aphasic population contributed to a bimodal distribution. Further study with more subjects is needed to test his hypotheses, particularly since Rosenbek, Wertz and Darley (1973) found a similar separation among their apraxics, which they also attributed to the severity dimension. During the editorial review of this paper, the possibility was raised that “a motor rather than sensory defect in the apraxics” could account for the findings for this group. This observation has substantial merit, and indeed, raises the methodological question of the contribution of the subjects’ manipulative behaviors (moving the test form around on the tongue) to oral stereognostic measurements. Controlled studies are needed relative to the manipulative variable with all client populations where application of oral stereognostic testing is anticipated. The four groups represented in the subject populations of the present study should be included in such investigations. Clinical Implications The results of the present study suggest that there is a sensory-perceptual deficit in apraxics and to a lesser degree in dysarthrics and aphasics. If this is so, articulation therapy with such clients may be directed toward heightening responsiveness to the patterns of auditory, proprioceptive and tactile sensations associated with the overlapping, ballistic movements of articulation (McDonald, 1964). Johns (1%8) further recommended providing auditory and visual cues to correct phoneme production while simultaneously teaching the patient to focus on auditory, visual and tactile-kinesthetic feedback provided by his own speech attempts. However, as Rosenbek (1970) stated: . urging the aphasic patient to attend the tactile-kinesthetic cues may be an uneconomical and frustrating experience for both clinician and client, especially if the patient suffers from extreme sensory deficit (Rosenbek, 1970, p. 108).
224
LOIS A. TEXEIRA,
RICHARD
H. DEFRAN
and ALAN
C. NICHOLS
He felt that a wiser procedure might be to proceed with a multisensory approach only insofar as visual, auditory and oral sensory-perceptual integrity is proserved as a system. If any modality is not intact, he suggested either (1) directing therapy only through intact input modalities or (2) using residual tactilekinesthetic ability during both verbal and nonverbal oral activities to try to determine whether gains in both sensory processing and speech production occur. The present study suggests the second alternative is feasible. That is, none of the apraxics scored 24 errors; all had some residual ability; 45% was the average. Preliminary work with several apraxic clients in our clinic has shown that they can improve in oral stereognostic discriminations. This was also a finding in the Wilhelm (1970) study with children as subjects. Our practice has been to employ alternate-discrimination and articulation-improvement procedures in therapy. Sensory focus upon articulators critical to the target phonemes is attempted during discrimination work, and the articulatory practice involves a multiple feedback model in which morphemes and longer utterances are attempted with the client’s intent directed toward the integration of feedback loops and linguistic content. The work has not been extensive enough to permit analysis. Clinical satisfaction has been expressed by clients and clinicians. The present article is based upon an M.A. thesis completed in 1972 by Lois A. Teixeira at California State University, San Diego, under the direction of the second and third authors. References Class, L.W. A comparative study of normal speakers and speech defectives with regard to the tactual-kinesthetic perception of form with the tongue. Masters thesis, The Ohio State University, 1956. Dunn, L.M. Peabody Picrure Vocabulary Test(Form B). Circle Pines, Minn.: American Guidance Service, Inc., 1959. Forster, F.M. Synopsis ofNeurology. Saint Louis: The C.V. Mosby Co., 1966. Guilford, A.M. & Hawk, A.M. A comparative study of form identification in neurologically impaired and normal adult subjects. Speech and Hearing Science Research Reports. University of Michigan, pp. 1-9, 1968. Johns, D.F. A systematic study of phonemic variability in apraxia of speech. Doctoral dissertation, Florida State University, 1968. Johns, D.F., & Darley, F.L. Phonemic variability in apraxia of speech. J. Speech Hearing Res., 1970, 13, 556-583. Kirk, R.E. Experimental Design: Procedures for rhe Behavioral Sciences. Belmont, Calif.: Wadsworth, 1968, pp. 494-498. Levin, S.I. A study of performance of normal subjects and aphasic subjects in tests of oral and manual stereognosis. Master’s thesis, The Ohio State University, 1965. McDonald, E. Articulation Testing and Treatment-A Sensory-Motor Approach. Pittsburgh: Stanwix House, 1964. McDonald, E.T., & Aungst, L.F. An abbreviated test of oral stereognosis. In J.F. Bosma (Ed.),
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DIFFERENCES
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Second Symposium on Oral Sensation and Perception. Springfield, Ill.: Charles C Thomas, 1970, pp. 384-390. Rosenbek, J.C. Oral sensation and perception in apraxia of speech and aphasia. Doctoral Dissertation, University of Colorado, 1970. Rosenbek, J.C., Wertz, R.T., & Dariey, R.L. Oral sensation and perception in apraxia of speech and aphasia. J. Speech Hearing Res., 1973, 16, 22-36. Schuell, H. Classification of aphasic patients. Aphasia in Adults. New York: Harper and Row, 1964. Schuell, H. Minnesota Tesf for Differential Diagnosis of Aphasia. Minneapolis: University of Minnesota Press, 1968. Siegel, S. Nonparametric Statistics for the Behavioral Sciences. New York: McGraw-Hill, 1956. Walker, H.M. & Lev, J. Statistical Inference. New York: Henry Holt and Co., 1953, pp. 423-425. Weinberg, B., Liss G.M., & Hillis, J. A comparative study of visual, manual, and oral form identification in speech impaired and normal speaking children. In J. F. Bosma (Ed.), Second Symposium on Oral Sensation and Perceprion. Springfield, Ill.: Charles C Thomas, 1970, pp. 350-356. Wepman, J.M., Jones, L.V., Bock, R.D., & Van Pelt, D. Studies in aphasia: Background and theoretical implication. J. Speech Hearing Dis., 1960, 323-332. Wilhelm, C.L. The effects of oral form recognition training on articulation in children.Doctoral dissertation, University of Kansas, 1970.