A theory of neurolinguistic development.

This article offers a developmental theory of language and the neural systems that lead to and subserve linguistic capabilities. Early perceptual experience and discontinuities in linguistic development suggest that language develops in four phases that occur in a fixed, interdependent sequence. In each phase of language, a unique ontogenetic function is accomplished. These functions have proprietary neural systems that vary in their degree of specialization. Of particular interest is an analytical mechanism that is responsible for linguistic grammar. This mechanism is time-locked and can only be turned on in the third phase. Confirming evidence is provided by children who are delayed in the second phase of the language learning process. These children store insufficient lexical material to activate their analytic mechanism. Inactivation behaves like damage, shifting language functions to homologous mechanisms in the nondominant hemisphere, thereby increasing functional and anatomical symmetry across the hemispheres. This atypical assembly of neurolinguistic resources produces functional but imperfect command of spoken language and may complicate learning of written language. The theory thus offers a different role for genetics and early experience, and a different interpretation of neuroanatomic findings, from those entertained in most other proposals on developmental language disorders.

A fatality due to alprazolam intoxication.

Alprazolam is one of the most widely prescribed benzodiazepines in the United States. It is generally considered a safe and effective drug for the treatment of anxiety disorders and panic attacks. Few overdoses that are due to the sole ingestion of alprazolam have been reported. This paper documents a fatality due to alprazolam intoxication and describes the distribution of alprazolam and an active metabolite, alpha-hydroxyalprazolam, in tissues obtained at autopsy. Qualitative identification of the drugs was achieved by full-scan gas chromatography-mass spectrometry, and quantitative analysis was performed by high-performance liquid chromatography. High concentrations of alprazolam were found in all specimens analyzed, but the metabolite was detected only in subclavian blood, urine, bile, and liver. A postmortem heart blood alprazolam concentration of 2.1 mg/L is the highest reported in the literature to date.

Why do infants begin to talk? Language as an unintended consequence.

Scholars have addressed a range of questions about language development, but for some reason have neglected to ask why infants begin to talk. Biologists often prefer 'how' to 'why' questions, but it is possible to ask about the immediate consequences of developing behaviours--an acceptable strategy for attacking causation--and psycholinguists can study the immediate consequences to the infant of behaviours that lead to linguistic competence. This process is demonstrated with a series of illustrative proposals as to the short- and long-term consequences of vocal learning and utterance storage, two developmental phases that lead to talking, as well as the act of talking itself. The goal is to encourage investigation of behavioural dispositions that nudge the child, by degrees, towards proficiency in the use of spoken language.

Emergent control of manual and vocal-motor activity in relation to the development of speech.

Babbling typically precedes, resembles, and conceivably facilitates development of speech, and yet there is no accepted neurobiological characterization of babbling. Here we report a study of infants' developing control of vocal behavior in relation to manual activity performed under differing conditions of audibility. We hypothesized that babbling is associated with the onset of left-lateralized motor control, as expressed in repetitive right-handed activity, and that audibility facilitates such activity. Sixty-one normally developing infants were seen before (N = 21) or at various intervals following (N = 40) the onset of babbling. In experimental trials, audible or inaudible rattles were placed in left or right hands equally often. Analysis of manual activity revealed little shaking movement in the youngest and vocally least differentiated infants, and a sharp increase in shaking in slightly older infants who had recently begun to babble. Surprisingly, audibility only marginally enhanced shaking activity. A dextral bias was evident in the shaking of infants who had recently begun to babble, but not in younger or older infants. These and other findings suggest that the left cerebral hemisphere may be disproportionately involved in the production of repetitive vocal-motor activity as occurs in babbling.

Gradual emergence of developmental language disorders.

This article presents a theory of normal and delayed development of language. According to the theory, linguistic capacity develops in critically timed phases that occur gradually and sequentially. Normally, the rapid accumulation of stored utterances activates analytical mechanisms that are needed for the development of linguistic grammar. Children with slowly developing brains have delays in the socially cognitive systems that store utterances, and a critical period for activation of experience-dependent grammatical mechanisms declines without optimal result. Continuing efforts to speak induct species-atypical allocations of neural resources into linguistic service. It is speculated that this compensatory activity leads to compensatory growth, which may ultimately be revealed as volumetric symmetry of perisylvian areas. Because rate of brain maturation is under genetic as well as environmental control, the stage is thus set for an impairment that will seem to be specific and a brain that will appear to be abnormal.

Thirty years of research on developmental neurolinguistics.

A body of medically important work has accumulated in the field of developmental neurolinguistics in the 30 years since Lenneberg set forth a research agenda for that field, consisting of the following: (1) the physiologic specialization or endowment for speech; (2) the genetic origin or natural history of vocalization and speech; (3) the nature of prelinguistic behavior, making possible the detection of any environmental (social) influences; (4) the development of motor-speech organization from birth; and (5) the limiting effects of deficient intelligence, hearing, and environmental stimulation. Subsequent study of these questions has established a genetic, neuroanatomic, and functional basis for such outwardly disparate disorders as dyslexia, stuttering, autism, and delayed language. Studies of emergent motor behavior suggest that babbling may index a state of neural maturation favoring expression of spoken languages. Based on studies of the congenitally deaf, mentally retarded, and other clinical populations it is now considered possible to detect early warning signs of developmental language disorders during the first year of life based on analyses of vocal turn-taking, gesturing, and utterance complexity.

Structure and stimulation in the ontogeny of spoken language.

Linguistic innateness is a fundamentally physical notion, which ultimately requires independent physical evidence. For spoken language, it is relevant to consider babbling, components of which are unaffected by ambient stimulation and are predicted by models of vocal tract function. Links between babbling and speech point to innate factors in the ontogeny of spoken language and invite attention to central control mechanisms. These neural capabilities enable oral language learning by providing children with control over an initial stock of speech-like movements and by directing their attention to salient linguistic patterns. Dispositions to attend to some cues are so strong that little stimulation is required. In other cases, predispositions are weak, and acquisition requires correspondingly more experience. To understand the ontogeny of language, we need to learn which cases are which and to know how these interactions occur and change over the course of acquisition.

Linguistic significance of babbling: evidence from a tracheostomized infant.

The role of babbling in language development is not well understood. One source of evidence is the utterances of infants who were tracheostomized during the period in which they would normally have produced syllabic vocalization. We describe here the phonetic patterns and linguistic development of a girl called Jenny. She was tracheostomized and generally aphonic from 0.5-1.8 but cognitively and socially normal, with near-normal comprehension of language. Acoustic analyses of Jenny's utterances following decannulation revealed a tenth of the canonical syllables which might be expected in normally developing infants, an extremely small inventory of consonant-like segments, and a marked preference for labial obstruents. In these ways, she resembled a group of infants of the same age who also cannot hear their oral-motor movements, the congenitally deaf, suggesting that the audibility of babbling contributes to its onset. Two months following decannulation, when Jenny was 1.10, she produced only a handful of different words. We think this is because aphonia prevented her from discovering the referential value of vocal expression and discouraged the formation of a phonetic repertoire that could be appropriated for lexical service. This unusual case suggests that babbling normally facilitates the development of language and speech.

Genetic factors in the ontogeny of spoken language: evidence from monozygotic and dizygotic twins.

Recent controversy about the innateness of language has awakened interest in the genetic basis of linguistic development. In this study, we analysed more extensively data from Mather & Black (1984) in order to test the hypothesis that the speech articulation of monozygotic (MZ) twins would be qualitatively more similar than that of age- and sex-matched dizygotic (DZ) twins. Analyses revealed that 4-year-old MZ twin pairs were significantly more likely to misproduce the same sounds on an articulation test than were DZ twin pairs, and that DZ twins were no more likely to share errors than were children who were both genetically and environmentally unrelated. There was no evidence that MZ twins made more similar errors than DZ twins, and indeed it was difficult to make this determination since only broad categories of error (substitution, distortion, omission) were available for analysis. The greater amount of genetic material shared by MZ twins, and the presumably more similar morphology of their speech mechanisms, may have caused certain sound patterns to be of more nearly equal difficulty for both members of a MZ pair. However, these findings need to be confirmed with phonetically more detailed analyses.

Angiosarcoma of the axillary vein.

Angiosarcoma is a malignant tumor of vascular origin. Malignant primary vein tumors are rare. The case of a 64-year-old patient who underwent a left forequarter amputation for angiosarcoma arising from the left axillary vein, a site not previously described, is presented. Also, the literature is reviewed.

Segmental infarct of the testis due to hypersensitivity angiitis.

We present a case of hypersensitivity angiitis causing a segmental infarction of the testis. The lesion presented as a discrete, palpable mass that led to orchiectomy. Hypersensitivity angiitis has not been reported previously to affect the testes or to produce a segmental infarct in any solid organ. A discussion is given of the vasculitides, especially periarteritis nodosa, that may involve the testes.

Stress-related rib and vertebral changes.

In the course of routine chest examination, 80 asymptomatic patients were observed to have localized hyperostosis of the posterior ribs and articulating transverse processes. The authors studied the distributions of lesions in these 80 patients, and records were reviewed in the 50 cases in which they were available. The occupational histories, male-to-female ratio (5:1), and ratio of right-to-left rib involvement (9:1)--in addition to results of electromyographic and histologic studies and the principles of bone remodeling--suggest that this hyperostosis occurs at sites most stressed with bending and rotation of the thorax. The authors hypothesize that this stress-related change occurs due to the pull of the iliocostalis thoracis muscle and is of no clinical significance.

The processing of printed language by aphasic adults: some phonological and syntactic effects.

Eight aphasic and eight brain-damaged nonaphasic patients silently "read" a short passage while performing an internal search for specified consonant letters of varying phonological and syntactic salience. The nonaphasic patients showed the phonological and syntactic effects customarily achieved by normal readers. For example, they were more likely to find a letter if it were pronounced than if it were silent, and they were more likely to find a letter if it were in a content word than in a function word. The aphasics had reliable phonological effects but no observable syntactic effects. Those aphasics with relatively large phonological effects performed better on a separate task requiring the oral reading of isolated words. For reading theory, the primary message from this study is that phonological recoding may occur between word recognition and the completion of semantic analysis, and that recoding may not by itself be sufficient to reading for meaning. For aphasia theory, the main implication of this study is that aphasics read by applying the appropriate phonological strategies, but that such strategies are limited in the face of ineffective syntactic and semantic processing, as occurs in aphasia.

The inference of speech perception in the phonologically disordered child. Part I: A rationale, some criteria, the conventional tests.

This paper considers the rationale and presents some criteria for assessing the speech perception of children with disorders at the phonological level of language. An examination of conventional test procedures suggests that none is useful in identifying clinically relevant perceptual disorders. However, readers are encouraged to inspect Part II (Locke, 1980), which describes procedures with more clinical promise.

The inference of speech perception in the phonologically disordered child. Part II: Some clinically novel procedures. Their use, some findings.

Several procedures used to assess speech perception of children with disorders at the phonological level of language are described. In most cases of segmental substitution, children discriminated target and substitution phonemes regardless of whether both were spoken by an adult, or one form was produced by an adult and the other was the child's internal representation of the target phoneme. However, in about a third of the cases there was consistent failure to discriminate the target phoneme from the substituted phoneme. Perceptual approaches to the treatment of sound production problems are questioned when perception is inferably differential. Certain phonetic effects, and their implications for theories of phonological acquisition and disorder, are discussed.

Phonetically mediated recall in the phonetically disordered child.

Children with phonology disorders frequently show reduced performance in short-term recall, inviting the assumption that impairment of memory may cause or help to cause the speech disorder. Ten children with marked phonology disorders were compared to 10 correctly speaking children on a test of short-term memory for sets of pictures whose names rhymed or did not rhyme. The phonologically disordered children performed significantly worse than those with correct speech and provided less evidence of phonetic mediation, a process commonly associated with enhanced levels of recall. Attention is drawn to the possibility that the disorder of phonology operated indirectly to reduce the efficiency of memory, though the question is complicated.