Search PubMed⌕ Search

PubMed · 7846250

Multi-modal hallucinations.

Abstract

A patient may experience hallucinations in more than one modality simultaneously or at different times and they may or may not appear to emanate from a single source. Current nomenclature is imprecise, often has particular diagnostic implications and fails to distinguish between these different phenomena. This has resulted in considerable confusion with a tendency to dismiss the importance of these symptoms. The various terms in current usage and the presence of these symptoms in a variety of different conditions are examined. To aid further research and improve clinical practice the authors advocate the use of the term multi-modal hallucinations and suggest operational criteria.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

L P Chesterman, N Boast. 1994. Multi-modal hallucinations.. https://doi.org/10.1159/000284883

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Chimaeric sounds reveal dichotomies in auditory perception.

By Fourier's theorem, signals can be decomposed into a sum of sinusoids of different frequencies. This is especially relevant for hearing, because the inner ear performs a form of mechanical Fourier transform by mapping frequencies along the length of the cochlear partition. An alternative signal decomposition, originated by Hilbert, is to factor a signal into the product of a slowly varying envelope and a rapidly varying fine time structure. Neurons in the auditory brainstem sensitive to these features have been found in mammalian physiological studies. To investigate the relative perceptual importance of envelope and fine structure, we synthesized stimuli that we call 'auditory chimaeras', which have the envelope of one sound and the fine structure of another. Here we show that the envelope is most important for speech reception, and the fine structure is most important for pitch perception and sound localization. When the two features are in conflict, the sound of speech is heard at a location determined by the fine structure, but the words are identified according to the envelope. This finding reveals a possible acoustic basis for the hypothesized 'what' and 'where' pathways in the auditory cortex.

Auditory Perception↗

The importance of rapid auditory processing abilities to early language development: evidence from converging methodologies.

The ability to process two or more rapidly presented, successive, auditory stimuli is believed to underlie successful language acquisition. Likewise, deficits in rapid auditory processing of both verbal and nonverbal stimuli are characteristic of individuals with developmental language disorders such as Specific Language Impairment. Auditory processing abilities are well developed in infancy, and thus such deficits should be detectable in infants. In the studies presented here, converging methodologies are used to examine such abilities in infants with and without a family history of language disorder. Behavioral measures, including assessments of infant information processing, and an EEG/event-related potential (ERP) paradigm are used concurrently. Results suggest that rapid auditory processing skills differ as a function of family history and are predictive of later language outcome. Further, these paradigms may prove to be sensitive tools for identifying children with poor processing skills in infancy and thus at a higher risk for developing a language disorder.

Auditory Perception↗

Specialist musical training and the octave illusion: analytical listening and veridical perception by pipe organists.

The octave illusion is a useful tool for investigation of the contribution of specialist training to auditory perception. The stimulus that induces the illusion involves two tones with a frequency ratio of 2:1, presented dichotically, and with ear of presentation reversed every 250 ms. Most listeners report hearing a single tone that alternates from high in the right ear to low in the left ear [Scientific American 233 (1975) 92-104]. The first experiment investigated the hypothesis that musical training contributes to veridical perception of an ambiguous stimulus. As hypothesized, participants with the highest level of musical training were more likely to perceive the stimulus veridically. Exploring the effects of specialist training, Experiment 2 contrasted expert pipe organists with other instrumentalists. As hypothesized, participants expert in playing pipe organ--an instrument with harmonic and spatial features similar to those of the octave illusion--were more likely to perceive the stimulus veridically. The results have implications for plasticity of the auditory system and the analytical listening that accompanies specialist, intensive training and rehearsal.

Auditory Perception↗