Production and Perception of Word Tones (Pitch Accents) in Patients with Left and Right Hemisphere Damage

BRAIN AND LANGUAGE ARTICLE NO.

53, 267–281 (1996)

0048

Production and Perception of Word Tones (Pitch Accents) in Patients with Left and Right Hemisphere Damage INGER MOEN Department of Linguistics, University of Oslo, Oslo, Norway AND

KJETIL SUNDET Rikshospitalet, Oslo, Norway The present paper addresses the question of the functional lateralization of tones in tone languages. Tonal perception and production of right-hemisphere-damaged (RHD) and left-hemisphere-damaged (LHD) speakers of East Norwegian were investigated. East Norwegian is a tone language with an opposition between two tones (pitch accents). The ability to distinguish auditorily between the two accents was normal in the RHD group but reduced in the LHD group. Tonal production was near normal in the RHD group, whereas the LHD group tended to have a production deficit.  1996 Academic Press, Inc.

INTRODUCTION

Pitch variation is a property of all natural languages. No language is spoken in a monotone. But pitch differences function differently in different languages. It is possible to divide languages into groups based on criteria related to different linguistic functions of pitch. One taxonomy of this type (Cruttenden, 1986) has three categories: (1) intonation languages, languages where differences in pitch are associated with phrases or sentences; (2) tone languages, languages which use differences in pitch for lexical purposes, like Thai, Chinese, and Vietnamese; and (3) pitch accent languages, languages where the pitch contrast is restricted to one syllable in a word. East Norwegian is a pitch accent language where pitch and stress are closely linked. The accented syllable is also stressed. Stressed syllables conWe are indebted to Eva Hofft for assistance in connection with the collection of the data, to Grete Usterud Fenstad for statistical assistance, and to Brain and Language’s reviewers for insightful comments. Address reprint requests to Inger Moen, Department of Linguistics, University of Oslo, P.O. Box 1102, Blindern, Oslo 0317, Norway. 267 0093-934X/96 $18.00 Copyright  1996 by Academic Press, Inc. All rights of reproduction in any form reserved.

268

MOEN AND SUNDET

sist of either a long vowel or a short vowel plus one or more consonants. Stress is not contrastive in Norwegian. In words where one or more unstressed syllables follow the stressed one, the stressed syllable will carry one of the two phonemically contrastive pitch accents, referred to as Accent1 and Accent2. The distinction between the accents is neutralized in monosyllabic words and words that are noninitial constituents in compounds. In these environments only Accent1 is possible. In East Norwegian, however, the contrast is not restricted to single lexical items. It is also present in phrases consisting of a monosyllabic word followed by another word, e.g., Accent1—ta pa˚ (touch) versus Accent2—ta pa˚ (put on). The choice between the accents is normally lexically determined. That is, the accent must be listed in the lexicon together with the word’s segmental phonological structure. Thus differences in pitch in Norwegian, as in Mandarin Chinese and Thai, are used to distinguish the lexical meaning of a word. In Norwegian there are a number of minimal pairs differing only in the pitch pattern of their accented syllable (superscripts 1 and 2 indicate Accent1 and Accent2, respectively): e.g., vannet/1vane/ (the water)—vanne/ 2vane/ (to water), skuffen/ 1skufen/ (the drawer)—skuffen/ 2skufen/ (the shovel), under/ 1uner/ (under)—unner/ 2uner/ (indulge/indulges). Both Accent1 and Accent2 are associated with a low pitch level in East Norwegian. Accent2 involves a fall in pitch from the beginning of the syllable to the end of the syllable or extending into the following unstressed syllable. Accent1 has its lowest pitch level earlier in the syllable than Accent2. There are two possible pitch patterns before the lowest pitch level in Accent1. The entire pitch pattern may be low level, or the low level may be preceded by a fall (Fintoft, 1970; Kristoffersen, 1990). The actual tonal contour in the two accents may therefore be very similar. The main difference between them is one of timing relative to the segmental structure of the word. The lowest point of the pitch contour occurs earlier in the syllable in Accent1 words than in Accent2 words (Kristoffersen, 1990). Fundamental frequency traces of an Accent1 and an Accent2 word are shown in Fig. 1. Investigations of accent perception in the normal population (Fintoft, 1970) have shown that identification of single words spoken in isolation is not always correct. Fundamental frequency is not the only acoustic feature differentiating between Accent1 and Accent2. Variations in segment duration—and possibly in formant structure—and in intensity may also play a part (for a discussion see Fintoft, 1970). However, variations in fundamental frequency is clearly the most important cue in the identification of the accents. Experiments have shown that listeners are able to identify the accent in words where the acoustic characteristics have been altered by means of peak clipping and low pass filtering (Fintoft, 1970). The result of peak clipping and low pass filtering is that the information carried by intensity variation and formant structure

WORD TONES AND BRAIN DAMAGE)

269

FIG. 1. Fundamental frequency traces of the Accent1 word 1tømmer and the Accent2 word tømmer.

2

is removed or drastically changed, whereas the fundamental frequency is kept unchanged. The studies that have addressed the question of possible functional lateralization of variations in pitch seem to indicate that the emotional use of pitch variation is the property of the right hemisphere (Ross, Harney, deLacoste-Utamsing, & Purdy, 1981; Tucker, Watson, & Heilman, 1977; Weniger, 1984; Edmondson, Chan, Seibert, & Ross, 1987; Ross, Edmondson, Seibert, & Chan, 1992), but when it comes to the linguistic functions of pitch, the evidence for lateralized processing abilities is less clear. The clinical-perceptual impression is that damage to either hemisphere may lead to deviations of sentence prosody. Acoustic investigations have revealed both normal and abnormal characteristics in the intonation of Broca’s and Wernicke’s aphasics and right-hemisphere-damaged (RHD) patients (Danly & Shapiro, 1982; Ryalls, 1982; Cooper, Soares, Nicol, Michelow, & Goloskie, 1984; Shapiro & Danly, 1985; Cooper & Klouda, 1987). It is, however, unclear as to what extent these abnormalities are linguistic in nature and to what extent they are caused by poor control of the physiological mechanisms associated with phonation and fundamental frequency variation, or the result of a deficiency in the long-range planning of linguistic units (for a review and discussion see Ryalls & Behrens, 1988). Dichotic listening studies of the perception of tones by normal Thai speakers (Van Lancker & Fromkin, 1973, 1978) and the perception of pitch accents by normal Norwegian speakers (Moen, 1993) have shown a right ear preference in tone/pitch accent perception, indicative of left hemisphere lateralization. Studies of tone production in the speech of aphasic speakers of Mandarin, Cantonese, and Thai indicate that left hemisphere damage may lead to deviant tone productions (Naeser & Chan, 1980; Packard, 1986; Gandour, Petty, & Dardarananda, 1988; Gandour, Ponglorpisit, Khunadorn, Dechong-

270

MOEN AND SUNDET

kit, Boongird, Boonklam, & Potisuk, 1992). The studies, however, do not present a unified picture (for reviews see Gandour, 1987; Gandour et al., 1988). The most noticeable discrepancy is that tone production seems to be more impaired in Chinese than in Thai aphasics. There is no apparent linguistic reason why this should be the case since the languages in question are tone languages of the same type. Gandour (1987) has pointed to possible confounding nonlinguistic variables which might have influenced the results: (i) different time spans between the onset of aphasia and the time of the investigation—some patients were investigated soon after the brain insult— and (ii) varying degrees of severity of aphasia in the investigated patients. A study by Gandour et al. (1988) attempted to control for these variables by investigating patients past the acute stage of aphasia and by correlating the individual results with the patients’ type of aphasia. They found that tone production was fairly resistant in a group of six aphasic speakers of Thai, a Wernicke, a transcortical motor, a conduction, a global, and two Broca aphasics. One of the Broca aphasics failed to distinguish clearly between two of the five Thai tones, and the global aphasic produced FO contours for all five tones which were quite different from those produced by a normal control group. This seems to indicate that a tone production deficit is manifested primarily in the acute stages of aphasia and that the deficiency is linked up with severity of aphasia. Gandour et al. (1992) in a follow-up study with a larger population confirmed this impression. Left hemisphere nonfluent speakers ‘‘signaled tonal contrasts at a lower level of proficiency. The extent of their impairment varied depending on severity level of aphasia’’ (p. 276). Ryalls and Reinvang (1986) investigated the production of Accent1 and Accent2 in three sets of minimal pairs by a group of five male right-hemisphere-damaged and five male left-hemisphere-damaged (LHD) speakers of Norwegian. The left-hemisphere-damaged patients had a nonfluent type of aphasia with good comprehension. Ryalls and Reinvang found that both groups of patients distinguished between the two accents. Although the FO contours of the patients’ productions were similar in shape to those of a control subject ‘‘there were some overall differences, at least visually, between the left-hemisphere and the right-hemisphere groups compared to the model tones’’ (p. 391). The contours of the LHD group looked ‘‘longer and flatter’’ than those of the RHD group. In order to quantify the visual impression of flatter contours in the LHD group, they introduced a measure referred to as the phono-acoustic difference. The phono-acoustic difference (PAD) is the difference in hertz between the initial frequency peak and the frequency minimum in Accent1 words subtracted from the corresponding frequency range of Accent2 words. Ryalls and Reinvang also introduced a measure of maximal duration for the tonal productions, calculated on the basis of the longest duration for any patient, and for a normal control, for each tone pair. In an informal perception test 27% of the LHD productions and 7% of the RHD productions failed to signal lexically acceptable contrasts.

WORD TONES AND BRAIN DAMAGE)

271

The aim of the present study is to investigate to what extent there may be a deficit in the perception and production of the Norwegian pitch accents in patients with right hemisphere damage and left hemisphere damage. PERCEPTION EXPERIMENT

Methods Subjects. The experiment involved two patient groups, a RHD group and a LHD group, with four patients in each group, and a normal control group of 10 persons. The patients were recruited from the pool of stroke patients who were receiving rehabilitation treatment at Sunnaas Hospital, Oslo, Norway. All patients had been routinely tested with the Neuropsychological Basic Assessment (Sundet, 1991). Patients with dysarthria, global aphasia, apraxia of speech, and neglect were excluded from the experiment. The patients selected for the experiment were male native speakers of East Norwegian with CT verified unilateral cerebrovascular infarction. The sample characteristics are shown in Table 1. The groups were similar with respect to age (52.8 vs 56.5 years) and time poststroke (5.3 vs 3.8 months). All but one patient were tested later than 8 weeks poststroke, thus representing a group of chronic CVA patients. Hemiplegia was present among all patients with the exception of two LHD subjects. Hemianopsia was diagnosed in two RHD patients. All patients were rated on the Sunnaas Activities of Daily Living Index (Vardeberg, Kolsrud, & Laberg, 1991). The tendency for RHD patients to be somewhat more help-dependent than LHD patients did not reach statistical significance. Standard neuropsychological tests showed impaired language comprehension (Token Test; DeRenzi & Faglioni, 1978) for all subjects in the LHD group whereas verbal concept formation (Similarities, WAIS; Wechsler, 1967) was mastered within normal limits for all but Broca1. Tests of visuospatial analysis (Raven’s Coloured Progressive Matrices; Raven, 1956) and visuomotor coordination in the unimpaired hand, ipsilateral to the site of infarction (Grooved Pegboard; Matthews & Kløve, 1964), showed no significant group differences. However, RHD3 attained impaired scores on these two tests. Thus, one subject in each group was marked with reduced cognitive functioning in accordance with site of lesion. Stimuli. The stimuli were a set of drawings illustrating the members of minimal pairs of words differing only with regard to accent type. The illustrations of each pair were placed above each other vertically. This was done in order to avoid any interference of a left or right visual preference—or neglect—in the subjects. Pictures, rather than orthographic representations, were used because many of the members of minimal pairs have identical, or near identical, spellings. The test words were chosen on the basis of their ‘‘picturability.’’ (See Appendix for a list of the minimal pairs.) Listening procedure. The subjects were presented with a pair of drawings. Test words were presented via a Sony TC-D5 PRO II cassette tape recorder, and the subjects were asked to point to the picture corresponding to the stimulus word. The test involved eight minimal pairs. The pairs were presented four times in such a way that each member was the target twice. In the analysis of the results the first set of presentations for each patient was discarded. The conclusions are thus based on 24 responses from each patient.

RESULTS AND DISCUSSION

The control group identified all the target words correctly. This cannot, however, be interpreted to indicate that any performance which is not fault-

Time poststroke (months)

(n 5 4) 2 3 3 7 3.8 2.2 n.s.

32 36 25 34 31.8 4.8 n.s.

22 28 10 32 23.0 9.6

Sunnaas ADL index (0–36)

34 26 28 33 30.3 3.9 n.s.

28 22 8 29 21.8 9.7

Raven CPM (0–36)

* Did not take part in the production experiment.

Left hemisphere group Broca1 54 Anomic1 51 Anomic2 72 Broca2* 49 Mean 56.5 SD 10.5 U-test n.s.

Right hemisphere group (n 5 4) RHD1 44 12 RHD2 56 2 RHD3 68 1 RHD4* 43 6 Mean 52.8 5.3 SD 11.8 5.0

Age (year)

15.5 28.5 19.0 7.0 17.5 8.9 p , .03

36.0 34.0 35.0 35.0 35.0 0.8

Token test (0–36)

4 8 8 11 7.8 2.9 n.s.

11 16 15 8 12.5 3.7

Similarities (WAIS) (0–19)

90 75 151 78 98.5 35.6 n.s.

90 74 331 74 142.3 126.1

Grooved pegboard: Ipsilateral hand (sec)

TABLE 1 Sample Characteristics

Broca Anomia Anomia Broca

Normal Normal Normal Normal

Speech/language impairment

Yes No Yes No

Yes Yes Yes Yes

Hemiplegia

No No No No

No Yes Yes No

Hemianopia

272 MOEN AND SUNDET

273

WORD TONES AND BRAIN DAMAGE)

TABLE 2 Matrices Representing Responses to the Two Accents by Subject Group Stimuli

Response Accent1

Accent1 Accent2 Total

43 9 52

Accent1 Accent2 Total

51 51

Accent2 LHD (n 5 4) 9 35 44

52 44 96

RHD (n 5 4) 1 44 45

52 44 96

Note. Stimuli accents are listed vertically and responses to the stimuli horizontally.

less is necessarily subnormal. As mentioned above, experiments have shown that members of the normal population also make mistakes in the identification of single words spoken in isolation. The RHD group’s performance was comparable to that of the normal controls: only one incorrect identification. In the LHD group, on the other hand, only one of the four patients, Broca2, identified all the target words correctly. Broca1 identified 50% of the words correctly, Anomic1 83%, and Anomic2 made 92% correct identification. Confusion matrices of the two patient groups’ responses to Accent1 and Accent2 stimuli, respectively, are shown in Table 2. Table 2 shows that the confusion between the two accents was bidirectional. Seventeen percent of Accent1 stimuli and 20% of Accent2 stimuli were reported as the other accent. When the wrong responses for each patient group are pooled (18 wrong responses of 96 for the LHD group and 1 wrong response of 96 for the RHD group) we find that the difference between wrong responses in the two groups is significant (t 5 4.11, p 5 .00004 , .05). In summary, the ability to distinguish auditorily between the two pitch accents was not impaired in the RHD group, in contradistinction to the LHD group where the performance varied from 100 to 50% correct responses. The unimpaired performance of the RHD group is not unexpected in view of the fact that dichotic listening experiments have demonstrated a right ear superiority in the perception of tonal contrasts (Moen, 1993; Van Lancker & Fromkin, 1973, 1978). Whether the performance of the LHD patients is due to residual mechanisms still operating within the damaged left hemisphere,

274

MOEN AND SUNDET

to mechanisms in the right hemisphere, or to subcortical mechanisms is a moot point. PRODUCTION EXPERIMENT

Methods Subjects, stimuli, procedure. Six of the patients took part in this experiment, three of the RHD patients (RHD1, RHD2, RHD3) and three of the LHD patients (Broca1, Anomic1, Anomic2). The stimuli consisted of six minimal pairs illustrated by drawings, with the target word written below each drawing. The minimal pairs were the same as those in the perception experiment, with the exception of pairs consisting of two words (tar pa˚, drar til). These may be pronounced in such a way that the tonal opposition is neutralized, and they were therefore left out of the production experiment. The patients were presented with one illustration at a time and asked to read the word written below the picture. Each member of a minimal pair was read once. The members of the same pair were not read consecutively. The subjects were tested in the hospital in a reasonably quiet room in a single setting. Their readings were recorded using a digital recorder, DAT Sony TCD-D10 PRO, and a unidirectional microphone, Sony ECM-672, placed approximately 30 cm in front of the subject’s mouth. The DAT recording was copied to an analog cassette via a Sony TC-D5 PRO II cassette player before being analyzed acoustically by means of a computer program (Computerized Extraction of Components of Intonation in Language, Summer Institute of Linguistics, 1990). Fundamental frequency traces (FO) were obtained, the PAD for the minimal pairs calculated, and the duration of the tonal productions measured. The PAD and the tonal durations were compared to the average values of normal controls, based on Fintoft’s average curves (1970). The recordings were also presented to a group of five normal controls in order to see if they were able to identify the targets. They were asked to identify each word by pointing to the corresponding drawing.

RESULTS AND DISCUSSION

A patient’s accent production is considered to be deviant if at least two of the minimal pairs, of the six, were produced in such a way that all five judges failed to identify a correct contrast. The ability to produce the distinction between the two pitch accents was more impaired in the aphasic patients than in the right-hemisphere-damaged patients. The three aphasic patients all failed to produce correct distinctions between the two accents in some of the minimal pairs. Only one RHD patient did not produce correct distinctions consistently (see Table 3). FO traces of the subjects’ productions support the judges’ impression, as can be seen in Figs. 2 and 3. Figure 2 shows FO traces of the accented syllables in Broca1’s pronunciations of 1kammer/ 2kammer, 1borde/ 2borde, 1tømmer/ 2tømmer, all perceived as Accent1 by the judges. The FO traces in Fig. 2 all show a narrow fall in the beginning of the accented syllable followed by a level contour, with or without a final rise—the typical Accent1 contour. Figure 3 shows the FO contours of the accented syllables of Anomic2’s pronunciation of 1kammer/ 2kammer, both perceived as Accent2 by the

WORD TONES AND BRAIN DAMAGE)

275

TABLE 3 Number of Minimal Pairs Produced with Correct/Incorrect Accent Contrast (n 5 6)

Broca1 Anomic1 Anomic2 RHD1 RHD2 RHD3

Correct

Incorrect

1 4 3 6 3 6

5 2 3 0 3 0

FIG. 2. FO traces of the accented syllables in Broca1’s pronunciation of 1tømmer/ 2tømmer, bordet/ 2borde, 1kammer/ 2kammer.

1

276

MOEN AND SUNDET

FIG. 3. FO contours of the accented syllables of Anomic2’s pronunciation of 1kammer/ 2kammer and 1tømmer/ 2tømmer.

judges, and 1tømmer/ 2tømmer, both perceived as Accent1. The first two traces are typical Accent2 contours and the other two typical Accent1 contours. FO contours of the deviant productions of Anomic1 and RHD2 were either too short to be revealing—accented syllables consisting of a short vowel followed by a voiceless consonant—or inconclusive. The general tendency is the same in our study as that in Ryalls and Reinvang’s, LHD patients being more impaired than RHD ones. However, our patients produced more unacceptable tonal contrasts than Ryalls and Reinvang’s. Since both studies involved a limited number of subjects, the difference could be ascribed to individual differences in the patient populations. Another possible reason might be the different elicitation techniques used. Confrontation naming may be more difficult than repetition for some patients. A comparison of the average PAD for the two patient groups was calcu-

WORD TONES AND BRAIN DAMAGE)

277

lated on the basis of the correctly produced tonal contrasts for each patient. In agreement with Ryalls and Reinvang’s study, the PAD for the LHD group (10.7) was smaller than that for the RHD group (21.7). The average PAD in Fintoft’s study was about 44. However, since Fintoft does not give any information about the within group variation of his data, and since we know that there may be considerable variation from person to person with regard to the fundamental frequency span of the initial fall in the two accents, it is not possible to decide, on the basis of the present data, whether the tone span for the brain damaged speakers is significantly narrower than for the normal population. Gandour et al. (1992) in the investigation of tonal production in brain damaged Thai speakers did not find that the FO range of the tone space was compressed. ‘‘Indeed, the right hemisphere, left hemisphere fluent, and left hemisphere nonfluent groups exhibit a wider range than the young normal’’ (pp. 301–302). The duration of our patients’ tonal contours is similar to the average duration of normal tonal contours in Fintoft (1970). Ryalls and Reinvang found that their patients produced abnormally long contours compared to their control subject. Hoever, compared to Fintoft’s curves the patient curves do not seem to be abnormally long. It is possible that Ryalls and Reinvang’s control subject had a fast speaking rate. This cannot be decided on the basis of Fintoft’s study which does not give any information about subject variability. It is noteworthy that most of the accent production mistakes in our investigation, 11 of 13, involved the substitution of Accent1 for Accent2. Accent1 is the unmarked accent, the pitch pattern used when the opposition between the two accents is neutralized, and it is the accent given to new loan words. Most of the accent substitutions thus involve the replacement of a marked feature by an unmarked one. According to the theory of Phonological Underspecification (see for instance Goldsmith, 1990) only one of the accents, the marked one, will be specified in the lexical phonological representation. The patients’ accent substitutions can be accounted for by assuming that Accent2 words occasionally are retrieved from the mental lexicon without accent specification. These words will then, by default, be assigned Accent1. Gandour et al. (1988, 1992), as already mentioned, found the ability to produce the tonal distinctions in Thai to be the function of both type and severity of aphasia. Our investigation seems to point in the same direction. Although all our patients were able to discriminate between the two pitch accents to a certain extent, the most impaired patient was a Broca aphasic. None of the patients in the present investigation, however, was severely aphasic. Relatively good comprehension, and also some ability to read single words, was required in order to master the test situation. This precluded the inclusion of severely aphasic patients. It is therefore possible that more serious disruption of the tonal contrast could have been demonstrated had we investigated a different clinical population.

278

MOEN AND SUNDET

GENERAL DISCUSSION

On the basis of investigations of the production and perception of intonation and stress in English and tone in East Asian tone languages, two hypotheses, ‘‘the functional scale hypothesis’’ (Van Lancker, 1980) and ‘‘the lexicalisation hypothesis’’ (Packard, 1986), have been put forward to account for the apparent left hemisphere specialization of tones as opposed to the more bilateral representation of stress and intonation. The functional scale hypothesis assumes a scale of pitch contrasts from the least grammatical use of pitch, associated with the right hemisphere, to the most grammatical use of pitch associated with the left hemisphere. This would account for the different lateralization of the perception of tones and the emotional use of intonation, features found at the opposite ends of the functional scale. A problem with this hypothesis, however, is that it is difficult to decide where to draw the demarcation lines between the various functions of pitch situated between the two extremes, because the scale represents a functional continuum and not a succession of discrete functions. The lexicalization hypothesis assumes that the functional lateralization of a prosodic feature is determined by whether the feature is specified in the mental lexicon. The basic assumption is that the phonological aspects of the lexicon are controlled by the left hemisphere. Segmental phonological deviations are generally the result of left hemisphere damage. Packard’s hypothesis assumes that lexical phonological contrasts signaled by pitch are controlled by the left hemisphere as well. This would account for the left hemisphere specialization of tonal distinctions in tone languages like Mandarin and Thai. The tonal contrasts are phonemic, and the shape of the FO contour associated with each of the tones in these languages must be specified in the lexicon. The lexical-phonologial hypothesis has been criticized as a theory of the functional lateralization of the ability to produce variations in fundamental frequency, because it does not accommodate the speech of those aphasic patients who seem to produce deviant FO contours as a result of reduced ability to control the timing of sentence and phrase-sized units. Since the tonal contrasts are tied to syllable sized units, the ability to produce correct tonal contours may be preserved in these patients even though their intonation is aberrant (Gandour, 1987). Production and perception, however, are not necessarily controlled by the same mechanisms, and a hypothesis about speech perception should not be rejected solely because it fails to account for production phenomena. The tonal contrast in Norwegian is phonological and part of the lexicon just like the tonal contrasts in Chinese and Thai. Both Van Lancker’s and Packard’s hypotheses would thus predict left hemisphere superiority in the perception of the tonal distinction in Norwegian. This prediction is confirmed by our investigation. The left-hemisphere-damaged patients were more im-

WORD TONES AND BRAIN DAMAGE)

279

paired than the right-hemisphere-damaged ones, with regard to the ability both to produce and to perceive the tonal distinction. In summary, the present findings are indicative of an impairment in perception and production of the tonal contrast in Norwegian LHD patients. The RHD patients demonstrated normal ability in the perception of the tonal contrast, and only one of the RHD patients failed to consistently produce an acceptable tonal contrast. The current findings may be interpreted as lending support to theories which hypothesize left hemisphere specialization for lexical phonological contrasts, including contrasts signaled by pitch (Van Lancker, 1980; Packard, 1986). It must be noted, however, that the investigation is based on a limited number of subjects with considerable within group variability. The conclusions must therefore be considered to be of a preliminary nature subject to confirmation by future studies. APPENDIX

Auditory stimuli løvet løve

/ 1lø:ve/ / 2lø:ve

the leaves lion

tømmer tømmer

/ 1tømer/ / 2tømer/

timber reins

bokser bokser

/ 1bokser/ / 2bokser

boxer (a dog) boxer (an athlete)

skuffen skuffen

/ 1skufen/ / 2skufen/

the drawer the shovel

kammer kammer

/ 1kamer/ / 2kamer/

chamber combs

Hun tar pa˙ ka˙pen Hun tar pa˙ ka˙pen

/hun 1ta:r po 2ko:pen/ /hun 2ta:r po 2ko:pen/

She touches the coat She puts the coat on

Han drar til kongen Han drar til kongen

/han 1dra:r til 2koŋen/ /han 2dra:r til 2koŋen/

He goes to the king He hits the king

De ga˙r fra bordet De ga˙r fra borde

/di 1go:r fra: 1bu:re/ /di 1go:r fra: 2bu:re/

They leave the table They leave the ship

REFERENCES Cooper, W. E., & Klouda, G. V. 1987. Intonation in aphasic and right-hemisphere-damaged patients. In J. H. Ryalls (Ed.), Phonetic approaches to speech production in aphasia and related disorders. Boston/Toronto/San Diego: Little, Brown and Company. Cooper, W. E., Soares, C., Nicol, J., Michelow, D., & Goloskie, S. 1984. Clausal intonation after unilateral brain damage. Language and Speech, 27, 17–24. Cruttenden, A. 1986. Intonation. Cambridge: Cambridge University Press.

280

MOEN AND SUNDET

Danly, M., & Shapiro, B. E. 1982. Speech prosody in Broca’s aphasia. Brain and Language, 16, 171–190. DeRenzi, E., & Faglioni, P. 1978. Normative data and screening power of a shortened version of the Token Test. Cortex, 14, 41–49. Edmondson, J. A., Chan, J.-L., Seibert, G. B., & Ross, E. D. 1987. The effect of right-brain damage on acoustical measures of affective prosody in Taiwanese patients. Journal of Phonetics, 15, 219–233. Fintoft, K. 1970. Acoustical analysis and perception of tonemes in some Norwegian dialects. Oslo: Universitetsforlaget. Gandour, J. 1987. Tone production in aphasia. In J. H. Ryalls (Ed.), Phonetic approaches to speech production in aphasia and related disorders. Boston/Toronto/San Diego: Little, Brown and Company. Gandour, J., Petty, S. H., & Dardarananda, R. 1988. Perception and production of tone in aphasia. Brain and Language, 35, 201–240. Gandour, J., Ponglorpisit, S., Khunadorn, F., Dechongkit, S., Boongird, P., Boonklam, R., & Potisuk, S. 1992. Lexical tones in Thai after unilateral brain damage. Brain and Language, 43, 275–307. Goldsmith, J. A. 1990. Autosegmental and metrical phonology. Oxford: Basil Blackwell. Kristoffersen, G. 1990. East Norwegian prosody and the level stress problem. Unpublished manuscript, University of Tromsø. Matthews, C. G., & Kløve, H. 1964. Instructional manual for the Adult Neuropsychology Test Battery. Madison: University of Wisconsin School. Moen, I. 1993. Functional lateralization of the perception of Norwegian word tones—Evidence from a dichotic listening experiment. Brain and Language, 44, 400–413. Naeser, M. A., & Chan, S. W.-C. 1980. Case study of a Chinese aphasic with the Boston diagnostic aphasia exam. Neuropsychologia, 18, 389–410. Packard, J. L. 1986. Tone production deficits in nonfluent aphasic Chinese speech. Brain and Language, 29, 212–223. Raven, J. C. 1956. Coloured progressive matrices. London: Lewis. Ross, E. D., Edmondson, J. A., Seibert, G. B., & Chan, J.-L. 1992. Affective exploitation of tone in Taiwanese: An acoustical study of ‘‘tone latitude.’’ Journal of Phonetics, 20, 441–456. Ross, E. D., Harney, J. H., deLacoste-Utamsing, C., & Purdy, P. D. 1981. How the brain integrates affective and propositional language into a unified behavioral function. Archives of Neurology, 38, 745–748. Ryalls, J. H. 1982. Intonation in Broca’s aphasia. Neuropsychologia, 20, 355–360. Ryalls, J. H., & Behrens, S. J. 1988. An overview of changes in fundamental frequency associated with cortical insult. Aphasiology, 2, 107–115. Ryalls, J., & Reinvang, I. 1986. Functional lateralisation of linguistic tones: Acoustic evidence from Norwegian. Language and Speech, 29, 389–398. Shapiro, B. E., & Danly, M. 1985. The role of the right hemisphere in the control of speech prosody in propositional and affective contexts. Brain and Language, 25, 19–36. Sundet, K. 1991. Nevropsykologisk Grunntest (NPG). Tidsskrift for Norsk Psykologforening, 28, 686–696. Tucker, D. M., Watson, M. D., & Heilman, K. M. 1977. Discrimination and evocation of affectively intoned speech in patients with right parietal disease. Neurology, 27, 947– 950. Van Lancker, D. 1980. Cerebral lateralization of pitch cues in the linguistic signal. Papers in Linguistics, 13(2), 201–277. Van Lancker, D., & Fromkin, V. A. 1973. Hemispheric specialization for pitch and ‘‘tone’’: Evidence from Thai. Journal of Phonetics, 1, 101–109. Van Lancker, D., & Fromkin, V. A. 1978. Cerebral dominance for pitch contrasts in tone

WORD TONES AND BRAIN DAMAGE)

281

language speakers and in musically untrained and trained English speakers. Journal of Phonetics, 6, 19–23. Vardeberg, K., Kolsrud, M., & Laberg, T. 1991. Sunnaas index of ADL. World Federation of Occupational Therapy Bulletin, 24, 30–36. Wechsler, D. 1967. Handbok for norsk utgave av WAIS (Manual for the Norwegian edition of the WAIS). Oslo: Norsk Psykologforening. Weniger, D. 1984. Dysprosody. In F. C. Rose (Ed.), Advances in neurology, Vol. 42: Progress in aphasiology. New York: Raven Press.