Effects of patient characteristics on delivery of token test commands by experienced and inexperienced examiners

JOURNAL OF COMMUNICATION

DISORDERS 11(1978), 325-333

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EFFECTS OF PATIENT CHARACTERISTICS ON DELIVERY OF TOKEN TEST COMMANDS BY EXPERIENCED AND INEXPERIENCED EXAMINERS ANTHONY P. SALVATORE* Audmlogy and Speech Pathology Service, Phoemx VA Hospital, Phoemx, Arizona 85012

MARCIA STRAIT Rtchfeld Public Schools, Richfield, Minnesota

ROBERT H. BROOKSHIRE Aphasta Section, Minneapolis VA Hosprtal, Minnesota 55417

Introductiun The Token Test usually is administered in live voice in clinical settings. DeRenzi and Vignolo (1962) state that the commands are to be read by the examiner, “. . . speaking with a clear and measured voice, without any special prosodic emphasis.” However, with these instructions, the clinician is free to vary the rate at which the test commands are administered. The possibility that an examiner may vary the rate at which he presents the test commands during the administration of the test is probably irnpoitant, since recent investigations have shown that the rate at which test commands are presented does affect an aphasic individual’s performance. It has been demonstrated that aphasic individuals make fewer errors to spoken commands when the rate of speech is slowed (Gordon, 1970; Parkhurst, 1970; Weidner and Johnson, 1974; Liles and Brookshire, 1975; Salvatore, 1975). During the administration of clinical tests, clinicians are assumed to present the test materials in a consistent manner. That is, it is hoped that clinicians would not be influenced during the test administration by the severity of the patient’s deficit or by his performance during the test. To investigate the possibility that clinicians may be influenced by these variables, two experiments were carried out. The purpose of the first experiment was to determine whether experienced or inexperienced examiners altered their rate of speech when administering the Token Test to low-level and high-level individuals. The purpose of the second experiment was to determine whether clinicians delivered test commands at a

*Address correspondence to: Anthony P Salvatore, Ph D , Audiology and Speech Pathology Servxe (126), 7th Street and Indian School Road, VA Hospital, Phoenm, Anzona 85012

C Elsewer North-Holland,

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slower rate following errors by aphasic individuals trial. Subjects Thirteen subjects were selected from patients diagnosed as aphasic at the Minneapolis and Pittsburgh VA Hospitals. To select subjects for the High-Level and Low-Level groups, a tape-recorded standard Token Test was delivered to patients from the treatment rosters. Eight patients who scored at least three correct responses on Part II, and four or fewer correct responses on Part III, were assigned to the Low-Level group. Five patients who scored six or more correct responses on Part IV and at least six wrong on Part V were assigned to the High-Level group. Examiners The Experienced Examiners were three speech pathologists who had administered the Token Test to aphasic individuals at least 100 times. The Inexperienced Examiners were four speech pathology undergraduate students who had taken one course in aphasia and had never administered the Token Test. Method Procedure

All tests were administered in adjoining single-wall audiometric rooms. The subject and the examiner were seated side-by-side at a table. A microphone was mounted over the table. The microphone was connected to the input of a Sony TC-650 tape recorder in the adjoining room. The output of the tape recorder was later connected to a graphic event recorder through Grason Stradler 1200 Series solid-state programming modules. From the graphic recordings thus generated, speech rate and pause duration could be computed by converting inches to seconds. Since an examiner can vary his speech rate by prolonging phonemes or by the insertion of pauses within test commands, the duration of each command and the duration of pauses within each command were measured. Pause intervals less than 250 msec were difficult to measure reliably; therefore, only pauses 250 msec or more in duration were included in the analysis. Before each session began, the experimenter read the following instructions to the examiner: Read each test command once Read each test command in a clear and measured voice, wxhout any special emphasis on certain words in the commands It is important that you mamtain an even mlkction

For this experiment, Parts I-IV of the Token Test were administered. To avoid

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order effects, examiners tested the aphasic subjects in random order. At each site all patients were tested by all examiners.

Experiment 1 The total duration of the commands for the two sets of examiners was compared using a two-tailed Student’s t-test for dependent measures. The results of the test indicated that commands delivered by the Experienced Examiners were longer in duration and thus slower in rate of speech than the speech rate of the Inexperienced Examiners (t = 2.69; dj = 25; P < 0.025). To determine more precisely the manner in which slower rates were generated, a further analysis was undertaken. The total pause time measured for each examiner was subtracted from the total command duration for each examiner. This difference was used as a measure of the “rate of articulation,” which permitted us to determine whether the slower rate of speech was accomplished by the prolongation of phonemes or by the insertion of pauses. A comparison of the articulation rates was carried out with a t-test. The results indicated no significant difference between the total duration of phoneme articulation for the two sets of examiners (t = 0.52; u” = 25; P > 0.05). These two measures indicate that the Experienced Examiners produced significantly longer commands than the Inexperienced Examiners; however, the two sets of examiners spoke at a similar rate of articulation. These results and the data shown in Fig. 1 suggest that the Experienced Examiners produced commands at slower rates of speech by inserting more pause time than their Inexperienced counterparts. To determine whether the two sets of examiners produced statistically meaningful differences in pause time, a t-test was computed on the differences in mean pause time between Experienced and Inexperienced Examiners. The results of the t-test indicate that the Experienced Examiners’ commands contained more total pause time than did Inexperienced Examiners’ commands (t = 4.30; df = 25; P < 0.01). A sign test (Siegel, 1956) computed on the same results contirmed the t-test (Nd = 23, x = 4, P = 0.002). The effects of patient severity on the performance of the two sets of examiners were also assessed. An examination of Figs. 2 and 3 suggests that both Experienced and Inexperienced Examiners tended to provide mote pause time to LowLevel subjects than to High-Level subjects. However, no High-Level subjects were seen at Pittsburgh VA Hospital, so it was thought advisable not to pool the data for a comparison across High and Low-Level subjects. t-Test (dependent measures) comparisons of the pause time produced by the two sets of examiners at Minneapolis VA Hospital testing High-Level and Low-Level subjects were accomplished. These results indicate that neither Experienced (t = 1.50, df = 9,

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examiners from P > 0.05) nor Inexperienced (t = 1.83, d’ = 9, P > 0.05) Minneapolis provided significantly different amounts of pause time when delivering commands to High- and to Low-Level subjects An important consideration in viewing these results is the great variability in pause time across examiners. For example, an examination of Figs. 2 and 3 shows that Experienced Examiner 1 provided more than twice as much pause time than Experienced Examiner 2. While Experienced Examiner 1 provided approximately the same amount of pause time to both groups of subjects, Experienced Examiner 2 provided almost twice as much pause time to the Low-Level subjects than to the High-Level subjects, Experienced Examiner 3, while providing similar amounts of pause time to Low-Level subjects, differed markedly from Inexperienced Examiners 3 and 4 in the amount of pause time provided to Low-Level subjects. This variability in the examiners’ use of pause time may make it difficult to interpret the results of the Token Test delivered in live voice. This variability in production of pause time by examiners may affect the performance of subjects. Figures 4, 5, and 6 show the number of correct responses made by each subject with each examiner. These data suggest that subjects tended to perform differently with the same, as well as with different, examiners. Exactly what examiner factor(s) or combination of factors are re-

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sponsible for the subject variability is difficult to assess from the present study. However, one variable to be considered is the differences in the amount of pause time used by the examiners. Data offered by Salvatore (1975) suggest that a pause duration shorter than 2 set has little effect on subject performance. In the present study (Experiment l), the longest mean pause time per command was only 1 set in duration. Therefore, it is difficult to see how pause durations, per se, could be offered as an explanation of the subject variability in performance found in the present study. Experiment 2

The purpose of the second experiment was to determine if examiners changed their rate of speech when they repeated commands after a subject had made an error. After completion of the first experiment, Experienced Examiners 2 and 3 and Inexperienced Examiners 1, 3, and 4 participated in a second experiment. Those examiners administered Parts III, IV, and V of the Token Teat to a number of subjects. The examiners were given the original instructions from Experiment

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1. In addition they were instructed to repeat a command that was responded to incorrectly until the subject responded correctly, or until the command had been delivered three times. After the third presentation, the examiner went on to the next command. Each of the repetitions was then compared to the initial delivery of the command to determine if the examiners varied their speech rate from initial presentation to subsequent repetitions of the command. A two-tailed sign test (Siegel, 1956) was used to test the null hypothesis that speakers did not change their rate of delivering commands following error responses. Experienced Examiners 2 (P < 0.004) and 3 (P < 0.0001) showed a significant increase in the number of times they increased the duration of commands following an error response. Inexperienced Examiners 1 (P < 0.007) and 4 (P < 0.0001) showed a similar effect as Experienced Examiners 2 and 3. However, Inexperienced Examiner 3 showed a significant (P < 0.05) decrease in the duration of the commands following an error response to the initial presentation of the command. Thus, of the five examiners studied, four slowed their rate of speech when repeating commands that had caused an error response. This result is consistent with a study by Longhurst and Siegel (1973) in which subject error responses resulted in examiners reducing their rate of speech when delivering instructions. However, one of the examiners in the present study increased her rate of speech on commands following an error response, which is a departure from the reported data. The present study suggests that examiners may have been influenced by stimuli not intended to control their presentation of Token Test commands. Examiners’ speech rates were influenced by subjects’ levels of severity, and by the occurrence of incorrect responses made by subjects. These findings suggest that the test either be presented via audio recording or by clinicians whose rate of delivery has been reliably established. These seem to be reasonable goals if we are to feel confident about our own test results and those of our comrades at other stations. The first author carried out this research while a NINDS postdoctoral research fellow at the Aphasia Section, VA Hospital, Minneapolis. A portion of this research was done by the second author in partial fulfillment of a M.A. degree at University of Minnesota. Other support was provided by the Research and Education Committee, Minneapolis VA Hospital. Special thanks to Dr. Dean Patterson, Chief of Audiology and Speech Pathology Service, and his staff at the Pittsburgh VA Hospital, particularly Dr. Albyn Davis. References DeRenzl, E aphasia

, Vlgnolo, L A The Token Test a sensltlve test to detect receptive disturbances Brain. 1%2, 85, 556-678

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Gordon, M A. Some effects of sttmulus presentation rate and complexity on perception and retentton m bratn-damaged patients Cortex, 1970, 6, 273-286. Lasky , E., Wetdner, W., Johnson, J Influence of lmgmstic complextty , rate of presentanon, and inter-phase pause nme on auditory-verbal comprehension of adult aphasrcs. Convention Program Summary, ASHA, 1974, p. 89. Ldes, B. Z., Brookshire, R. The effects of pause time on auditory comprehenston of aphastc subjects J Commun. Dis., 1975,8,221-235 Longhurst, T. M., SIegeI, G M. Effects of commumcation failure on speaker and listener behavror J. Speech Heanng Res., 1973, 16, 128-140. Parkhurst, B G The effect of time altered speech sumuli on the performance of right hermplegtc adult aphasics. Convention Program Summary, ASHA, 1970, p 63 Salvatore, A. P. An investtgation of the effects of pause duration on sentence comprehenston by aphasic subjects Convennon Program Summary, ASHA, 1975, p. 115 Siegel, G. Nonparamernc statisticsfor the behavior snences. New York: McGraw-Hill, 1956. Weidner, W. E., Lasky, E. Z. The interactton of rate and complexity of stimuli on the performance of adult aphasic subjects. Eratn Lang , 1976, 3, 34-40. Winer, B. M. Statistical princrples in erperimenral design. New York McGraw-Hill, 1%2