- 1 Guide to reviewing literature on apraxia Vol. 1
- 1.1 1. Origin ofthe distinction between ideational apraxiavs. ideomotor apraxia
- 1.2 2. Criteria for the distinction between ideational apraxia and ideomotor apraxia
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- 1.5 3. A useful classification of the gestures considered in the assessment and diagnosis of apraxia
- 1.6 4. Glossary
- 1.7 5. Notes on possible confusion arising from the use of language and translation
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- 2 Index of the brief guide to reviewing literature on apraxia Vol. 2
- 3 Bibliography
Sometimes, when looking up different sources on apraxia, we can find no agreements among the different definitions, classifications, diagnostic criteria or nomenclatures of movements given by the different manuals or authors.
This blog post tries to bring simplicity to the reading on apraxia and better understanding by highlighting aspects of the literature that can be a potential source of confusion for readers and providing some keys to unraveling important concepts.
This is the first installment of two volumes which I hope you will find useful as a guide to reviewing literature on apraxia. At the end of the post, I’ll give you the index of the second volume (coming soon). I hope all this will be of help.
Guide to reviewing literature on apraxia Vol. 1
1. Origin ofthe distinction between ideational apraxiavs. ideomotor apraxia
Regarding the literature on limb apraxia, the most prevalent distinction is between ideational apraxia and ideomotor apraxia.
This classification derives from the model proposed by Hugo K. Liepmann in 1920 , which combined the physiological and psychological approach of apraxia in a model of motor control providing an anatomical basis for the clinical literature of the late 19th century [2, 3].
Liepmann was the first to propose this modelfor apraxia[2,3],and suggested that the cerebral basis of action control is a stream that connectsposterior cortical areas with the motor cortex and converts the conscious mental imagesof the intended motor action, into the motor commandswhich direct execution of the movement [2,3].
According to this understanding of motor control, apraxia could then be due either to insufficient generation of the concept (conscious mental images), or to the disruption of the posterior-anterior stream, which would prevent the concept from becoming motor commands.
The sequence of conception and production is the basis for distinguishing between ideational apraxia(due to insufficient generation of the concept of movement) and ideokinetic apraxia (due to its insufficient conversion into motor execution), which was later renamed ideomotor apraxia[2, 3].
Therefore, by accepting this classification, we are also assumingmore or less implicitlythat there is a higher cognitive level and a lower motor level of action control and that they may be selectively altered.
2. Criteria for the distinction between ideational apraxia and ideomotor apraxia
The major source of confusion when reviewing different texts on apraxia may be the remarkable lack of consensus and the variability found in the clinical criteria used to distinguish between the two main types of limb apraxia:ideational apraxia and ideomotor apraxia.
Researchers in general are interested in finding alterations in someparticular type of gesture, leading to a specific type of apraxia  and thus define ideational and ideomotor apraxia according to one or more of the following criteria:
- Altered gesture type (transitivevs. intransitive; meaningfulvs. meaningless; pantomime of tool use).
- The pathway through which the gesture is assessed(visual pathway throughimitation and verbal pathwayby means of commands).
- Error typemade in gesture production(content errors, synchronization errors, sequencing errors, omission errors, misuse errors etc.).
Some authors consider that a deficit of transitive gestures is characteristic of ideational apraxia, while ideomotor apraxia affects the imitation of meaningless gestures .
Other authors consider that these two types of apraxia are associated with errors made in gesture production, and therefore associate ideational apraxia with content errors, which affect transitive gestures and pantomimes .
There are those who describe ideational apraxia as a deficit in the production of meaningful gestures , and those who interpret ideomotor apraxia as a deficit in gesture pantomime and gesture imitation characterized by spatiotemporal errors in those types of action .
And so on and so forth.
Therefore, using a taxonomy of limbapraxiaentails risk  because the criteria are not shared by all authors and there is no universal diagnostic classification.
See the glossary below to remember the different types of gestures (transitive, intransitive, etc.).
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3. A useful classification of the gestures considered in the assessment and diagnosis of apraxia
To have a clear, schematic view of the types of gestures often cited in publications on apraxia, Goldenberg’s review  of Liepmann’s diagnostic criteria and logic may be useful in distinguishing between ideational and ideomotor apraxia.
Liepmann considered defective manipulation of real objects as a clinical criterion for defining ideational apraxia, and defective performance of empty-handed gestures for diagnosing ideomotor apraxia .
Liepmann’snrationale for making the distinction was that real objects provide guidance and support to the hands, while empty-handed execution of gestures does not;therefore,empty-handed gestures can be used to examinethe entire route, from the mental image to motor execution .
Thus, empty-handed gestures include meaningless and meaningful gestures, and within the latter, gestures with conventional meaning (e.g., ‘military salute’ or ‘OK’gesture) and pantomime of tool use.
Movements made when manipulating real objects are called transitive gestures  while gestures with conventional meaning are namedintransitive gestures .
For a description of these gestures, see the glossary below.
All of these gestures can be tested inimitation (visual pathway) or on verbal command (auditory pathway), except for meaningless gestures, which are usually tested only in imitation, because their verbal description mayovertaxlanguage comprehension in patients with aphasia . Pantomimes can also be testedby touch.
In my experience, I have found it helpful to integrate Liepmann’s classification of movements with the most widely used nomenclature found in the articles. Here I include it in the following diagram:
- Transitive gesture: gesture performed with a real object (e.g.,show the examiner how to use a pair of scissors).
In both English and Spanish literature, the term transitive is used, probably because of the parallelism of the use of this term in grammar when referring to verbs; in both languages, a transitive verb is a verb that requires a direct object, that is, a clause element whichindicates the person or thing affected by the action of the verb [5,6].
This may be useful for readers to determine when a gesture is transitive or when it is intransitive.
- Intransitive gesture: gesture performed without a real object. Intransitive gestures have alsobeen namedexpressive, symbolic or communicative movements performed without objects (e.g., waving goodbye) that may vary across cultures .
Intransitive gestures are equivalent togestures with a conventional meaningmentioned earlier, which have also been called emblems (emblems,symbols) .
Other times in the articles, intransitive is synonymous withcommunicative, given the communicative nature of symbols and conventions [3, 4].
- Meaningful gestures:include transitive and intransitive gestures and pantomimes .
- Meaningless gestures:gestures that have no meaning for a particular population (e.g., placing thefist under the chin) .
- Pantomimes (of tool use):gestural description of the use of the object. Subjectsare asked toimagine using a tool as if they were holding the actual tool in the hand.
5. Notes on possible confusion arising from the use of language and translation
- When talking about pantomimes, one can sometimes confusethereference made about patients “imitating” the movement they would make if they were using a certain tool (imitating in the sense of representing)with references to imitation as a means for assessing apraxia (the examiner asks the subjects to imitate what he/she does, but this is different from asking them to perform a pantomime).
In English, the use of ‘pantomime’ as a verb does not give rise to confusion, but sometimes the terms ‘to imitate’ or ‘imitation’ can be found when referring to a patient performing a pantomime that has been requested by the examiner on verbal command, and that is being assessed without visual object presentation.
- When speaking of meaningful and meaningless gestures, English literature often uses these exact terms, which, when translated into Spanish in some texts,appear as significant and insignificant gestures, rather than as gestures with or without meaning.
Although meaning and significance are synonyms in English, and both refer to the importance of something, meaning has a connotation of symbolic value and also of intention ; hence, it may be more appropriate to translate meaningful and meaningless gestures as gestures with and without meaning, rather than as significant and insignificant gestures, as the latter expressions in Spanish seem to give the idea of important and unimportant gestures (just as when we use the expression “significant significance” in statistics).
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The next installment of this brief guide to reviewing literature on apraxia (volume 2) will include the following topics:
Index of the brief guide to reviewing literature on apraxia Vol. 2
- Definition of apraxia as a disorder of learned movement.
- The double meaning of ideational apraxia.
- Criteria for ageneral classification of apraxia.
- A comprehensive classification of apraxia.
- More notes on possible confusions arising from the use of language and translation.
See you soon!
By Lidia García Pérez
If you liked this brief guide to reviewing literature on apraxia, you might find the following posts interesting as well:
- Ángel Sánchez continues answering questions from his presentation “Functional consequences of apraxia”
- Aphasia: Differential Diagnosis
- Activities for the neuropsychological rehabilitation in patients with Broca´s aphasia
- Liepmann H. Apraxie. In: Brugsch H, editor. Ergebnisse der gesamtenMedizin. WienBerlin: Urban&Schwarzenberg; 1920. p. 516–43.
- Goldenberg (2014a). Challengingtraditions in apraxia.Brain, 137, 1854-1862.
- Goldenberg (2014b). Thecognitiveside of motor control.Cortex, 57, 270-274
- Bartolo, A. &Ham, H. S. (2016). A CognitiveOverview of Limb Apraxia.CurrentNeurology and NeuroscienceReports, 16(8), 75.
- Real Academia Española (s.f). [Diccionario de la lengua española]. Retrieved on 28 April 2018 fromhttp://dle.rae.es/?id=bbVXlxq
- Cambridge Dictionary (s.f). [Diccionario de inglés]. Retrieved on 28 April 2018 fromhttps://dictionary.cambridge.org/es/diccionario/ingles/transitive
- WikiDiff (s.f).Significance vs Meaning – What’sthedifference? Retrieved on 28 April 2018 from https://wikidiff.com/content/significance-vs-meaning-whats-difference-0
- Confabulations (Vol. II): theoretical models - February 5, 2019
- Confabulations (Vol. I): classification, neuropathology and cognitive mechanisms - January 29, 2019
- The cognitive mechanisms of errorless learning - October 23, 2018