Prasert Boongird

Neurological manifestations of gnathostomiasis

Neurological features of 24 patients with nervous system gnathostomiasis were reviewed. The commonest presenting features were radiculomyelitis or radiculomyelitis terminating with encephalitis, and subarachnoid haemorrhage. A primary encephalitic form was noted in 2 patients. The salient feature of the disease was a sudden onset of extremely severe radicular pain and/or headache followed by paralysis of the extremities and/or the cranial nerves. Migration signs were also the hallmark of nervous system gnathostomiasis. No single area of the nervous system was inaccessible to the highly invasive gnathostome lava. Multiplicity and/or rapid progress of lesions beyond the degree of cerebral oedema could only be explained by further migration of the parasite. Death occurred in 6 patients from direct extensive involvement of vital centres in the brain stem or from complications such as pneumonia or septicaemia. Multiple cranial nerve palsies were usually bad prognostic signs.

Lexical tones in Thai after unilateral brain damage

An acoustic perceptual investigation of the five lexical tones of Thai was conducted to evaluate the nature of tonal disruption in patients with unilateral lesions in the left and right hemisphere. Subjects (n = 48) included 10 young normal adults, 10 old normal adults, 11 right hemisphere nonaphasics, 9 left hemisphere fluent aphasics, and 8 left hemisphere nonfluent aphasics. The five Thai tones (mid, low, falling, high, rising) were produced in isolated monosyllables, presented for tonal identification judgments, and measured for fundamental frequency (Fo) and duration. Results of an analysis of variance indicated that left hemisphere nonfluent speakers signaled and tonal contrasts at a lower level of proficiency. The extent of their impairment varied depending on severity level of aphasia. When compared to normal speakers, tonal identification for less severe nonfluent aphasics differed more in degree than in kind, and for more severe nonfluent aphasics differed both in kind and in degree. Acoustic analysis revealed that with the exception of one left nonfluent, average Fo contours were comparable in shape across speaker groups. Variability in Fo production, however, was greater in left nonfluent speakers than in any of the other four groups of speakers. Issues are discussed regarding the extent and nature of tonal disruption in aphasia and hemispheric specialization for tone production.

Intraword timing relations in Thai after unilateral brain damage.

The present study examined temporal characteristics of monosyllabic, bisyallabic, and trisyllabic words in Thai to evaluate timing control at the word level in brain-damaged patients. Subjects included young and old normal adults, right hemisphere patients, and left hemisphere nonfluent and fluent aphasic patients. Utterances were produced at a conversational speaking rate. Results indicated that, on an absolute or relative measurement scale, magnitude of the shortening effect on nonfinal syllables in polysyllabic words was significantly smaller in left nonfluent aphasics than in other groups. In trisyllabic words, duration of the penultimate syllable for left fluent aphasics was also significantly longer than that of normals. Left nonfluent and fluent aphasics were significantly more variable than other speakers in their production of bisyllabic and trisyllabic words. Findings are discussed in relation to issues pertaining to the nature of timing deficits in nonfluent and fluent aphasic patients.

Timing characteristics of speech after brain damage: Vowel length in Thai ☆

This paper explores the extent of timing deficits in vowels produced by brain-damaged speakers of a language with a phonological contrast in vowel length. Short and long vowels in Thai were produced in isolated monosyllabic words by 20 normal adults, 14 right hemisphere patients, and 17 left hemisphere aphasics. Vowel durations were measured spectrographically. Although the phonological contrast was relatively preserved, as indicated by average duration, a subtle timing deficit in vowels produced by nonfluent aphasics was indicated by a compressed duration continuum and increased variability in vowel production.

Tonal coarticulation in Thai after unilateral brain damage.

The magnitude and temporal extent of anticipatory and perseverative tonal coarticulation was investigated in Thai-speaking normal and brain-damaged adults. A total of 47 speakers (10 young normal, 10 old normal, 13 nonaphasic right-brain-damaged patients, 14 left-brain-damaged aphasic patients, 9 fluent, 5 nonfluent) produced all 25 possible sequences of two tones from the five lexical tones of Thai embedded in a carrier sentence. F0 contours were analyzed in terms of height and slope at 10% intervals throughout the duration of the two syllables. Acoustic analysis revealed that anticipatory and perseverative tonal coarticulation of tones was markedly reduced in left fluent aphasics, totally absent in left nonfluent aphasics, but reasonably intact in right hemisphere patients. Findings are interpreted to highlight the nature of speech disturbances in nonfluent and fluent aphasia, hemispheric specialization for tone, and tonal coarticulation in Thai.

Radiculomyelitis complicating acute haemorrhagic conjunctivitis: A clinical study

Fourteen patients with radiculomyelitis following acute haemorrhagic conjunctivitis (AHC) were seen in Bangkok during October to December 1974. Most patients developed weakness of extremities 2 weeks after AHC. Prodromal symptoms consisted of fever and malaise for a few days, followed by the acute onset of root pain in the legs and flaccid paralysis. Knee and ankle reflexes were absent or diminished. Cerebrospinal fluid examination revealed lymphocytosis and an increase in protein. Electromyographic findings were consistent with anterior horn cell or motor root lesions. Ten of the 12 cases in which virological studies were performed showed definite serological evidence of AHC virus infection. Six patients received corticosteroid treatment but apart from relief of pain no significant improvement was seen. Motor weakness in 10 patients was less at the end of 2 months, but in 4 it remained unchanged. The occurrence of disabling neurological sequelae calls for effective public health control of AHC outbreak.

Interaction between Tone and Intonation in Thai after Unilateral Brain Damage

Intonational characteristics of Thai sentences were used to evaluate fundamental frequency (F(0)) control in brain-damaged patients with unilateral left and right hemisphere lesions. Subjects (n = 41) included 9 young and 10 old normal adults, 12 right hemisphere patients, and 10 left hemisphere aphasic patients (7 fluent and 3 nonfluent). Sentences were comprised of six words, three of which were keywords occurring in sentence-initial, -medial, and -final positions. All 125 possible sequences of three of the five Thai tones (mid, low, falling, high, rising) were superimposed on monosyllabic keywords. Utterances were produced at a conversational speaking rate. Average F(0) of keywords was analyzed as a function of sentence position, tone, and group. For both normal and brain-damaged speakers, results indicated that tones in sentence-final position were significantly lower in F(0) than in either sentence-initial or -medial position; falling and high tones were significantly higher in F(0) than mid, low, and rising tones. Findings are discussed in relation to issues pertaining to hemispheric specialization and the nature of F(0) deficits in nonfluent and fluent aphasic patients.

Stop voicing in thai after unilateral brain damage

Abstract Word-initial bilabial stops (/b p ph/), alveolar stops (/d t th/), and velar stops (/k kh/) in Thai were produced by 20 normal adults (10 young, 10 old), 12 non-aphasic patients with unilateral right hemisphere lesions, and 17 aphasic patients with unilateral left hemisphere lesions (nine fluent, eight non-fluent). Voice onset time (VOT) was measured from broad-band spectrograms. Relative frequency distributions of VOT values indicated minimal or no overlap between homorganic stop consonants for normal speakers, only sporadic occurrences of overlap for right hemisphere speakers, slightly more overlap for left fluent speakers, and even more overlap for left non-fluent speakers. By group, mean VOTs of homorganic stop consonants differed for all groups except /d t/ for the left non-fluent. By voicing category, mean VOTs of /b d/ for the left non-fluent group were shorter than those of other groups, and mean VOT of /k/ was longer than those of other groups. Mean VOTs of /ph th kh/ for the old normal ...

Speech Timing in Thai Left-and Right-Hemisphere-Damaged Individuals

An acoustic analysis of syllable duration in short Thai phrases was conducted to evaluate the effects of focal brain damage on the control of speech timing. Almost all 35 of the subjects had participated in each of four previous companion studies: 13 left-brain-damaged (6 nonfluent aphasics; 7 fluent aphasics), 14 right-brain-damaged patients, and 8 normal controls. Somewhat surprisingly, results revealed relatively normal timing patterns in 3-syllable phrases in all subject groups. A comparison of the current study and the four others, however, led us to conclude that Thai-speaking nonfluent aphasics exhibit a speech timing deficit regardless of the linguistic level of representation, whereas timing deficits in fluent aphasics appear to be restricted to units larger than a syllable. Speech timing, on the other hand, appears to be intact across the board in right-brain-damaged individuals. Findings are brought to bear on theories of temporal control in brain-damaged patients.

Anticipatory Tonal Coarticulation in Thai Noun Compounds after Unilateral Brain Damage

The time course and extent of anticipatory coarticulation between tones was investigated in normal and brain-damaged Thai-speaking subjects. Subjects were classified into five groups including 11 young normal, 9 old normal, 12 right hemisphere, 9 left hemisphere fluent, and 6 left hemisphere nonfluent. Stimuli consisted of five bisyllabic noun compounds with a falling tone on the initial syllable and each of the five Thai tones (mid, low, falling, high, rising) on the final syllable. Height and slope of F0 was measured at 10% intervals throughout the duration of the initial syllable. Results indicated anticipatory effects on both height and slope of the falling tone. Height effects extended throughout from the beginning. The falling tone was generally higher when occurring before the low/rising tones than when occurring before the mid/falling/high tones. Slope effects were restricted to the terminal portion. The falling tone before low/rising tones exhibited a steeper slope than before falling/high tones. In magnitude of effect, patients with left and right hemisphere lesions were statistically indistinguishable from those of normal subjects. No differences were noted in coarticulatory patterns as a function of aphasia type. All brain-damaged speakers were more variable in F0 production than normals. Findings are interpreted to highlight properties of nonfluent aphasic speech and neurological bases of speech production.