**Neurocognitive Implications of Tangential Speech in Patients with Focal Brain Damage Patients with Focal Brain Damage**

**Neurocognitive Implications of Tangential Speech in** 

DOI: 10.5772/intechopen.71904

Nora Silvana Vigliecca Nora Silvana Vigliecca Additional information is available at the end of the chapter

[61] Folstein M, Folstein S, McHugh P. MMSE (Bulgarian version). In: Jablenski A, editor.

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[73] Arenberg D. Differences and changes with age in the BVRT. Journal of Gerontology.

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DOI: https://doi.org/10.1093/bmb/ldp033

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.71904

#### **Abstract**

There are no studies on the neurocognitive implications of tangential speech (TS). This research aims to take a step forward in the study of narrative processing, by evaluating TS in a sample that helps to detect this deficit when it is neurogenic and recently manifested. The relationship between TS, secondary to focal brain injury, and neuropsychological and neuroanatomical variables was explored. A comprehensive neuropsychological battery was administered to 175 volunteers: 95 alert inpatients, without aphasia, without psychiatric history and without TS history, and 80 healthy participants, without TS. Results: TS (prevalence 16%) was independent of type or site of injury. An adverse effect of TS on global neuropsychological performance was observed. This effect was significantly related to attentional errors along with prolonged processing times but not to correct responses. Reliability and validity indices for the present TS screening scale were provided. Conclusion: Present results support the hypothesis that this neurogenic inability to spontaneously find, organize and communicate verbal information, beyond single words, depends on extended brain networks involving processes such as sustained attention, complex-syntax comprehension, the (implicit) interpretation and spontaneous recall of a narrative, and emotional and behavioral alterations. Early TS detection is advisable for prevention and treatment at any age.

**Keywords:** communication disorders, language disorders, disconnected speech, focal cerebral lesions, goal-directed speech, mild cognitive impairment, narrative processing, sustained attention, time of day orientation

#### **1. Introduction**

The organization of spoken language involves the selection and maintenance of the topic of the conversation (with logical sense and pertinence) according to the context and the

Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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listener. Ferstl et al. [1] affirm that language processing in context requires more than merely comprehending words and sentences: important processes such as inferences for bridging successive utterances, the use of background knowledge, discourse context and pragmatic interpretations need to be considered. Besides, the study of language processing in context also requires the analysis of its behavioral or expressive mechanisms, in particular, the presence of failures in goal-directed speech. Considering the method of analysis on these mechanisms, it is probable that the presence of failures in the quality and consistency of the discourse can be screened with a single (but comprehensive) measure, thus avoiding fragmentation into multiple variables, as previously considered in the field of communication disorders (see, e.g., [2]).

This study may represent the first attempt in the scope to generate hypotheses about a feature that usually has been explored as part of the larger attribute of pragmatics, with

Neurocognitive Implications of Tangential Speech in Patients with Focal Brain Damage

ability, and taking into account that discourse processing has been considered a typical skill associated with pragmatics, some of the measures which have been previously reported as valid indicators of discourse processing (see, e.g., [8–10]), were included in the present

The evaluation of spontaneous speech is a crucial step in any neuropsychological assessment to detect aphasia, but not to detect TS. Probably this is so because a simple easy-to-administer scale for measuring this comprehensive behavior has not been designed yet, particularly in clinical settings and for screening purposes. To design such a TS scale, the analysis (and even-

Harvey and Bowie [11] described two types of disturbances in the production of goaldirected speech as common symptoms in schizophrenia: verbal underproductivity and disconnected speech. The first is characterized by a reduction in the amount of speech or in the breadth of information; the second, by illogical or tangential connections between words or sentences as a result of which the speaker often fails to return to the goal of the

In the field of brain injury, unlike the above described classification, disconnected or underproductive discourses could in principle suggest either delirium (involving disturbance/ clouding of consciousness) or aphasia (involving lack/impairment of fluency or naming). Discarding delirium and aphasia such types of verbal symptoms may mimic psychiatric ones which, incidentally, have been considered for some authors manifestations of right hemi-

Some of the neuropsychiatric constructs that have been cited together with TS are quite similar in many respects to TS, in particular when the attributes of coherence, consistency, stabil-

Tanner [17] stated that logorrhea is a garrulous and incoherent talking; the speech is rambling and has no point or conclusion; words are not connected semantically. The author also states that TS lacks of continuity and consistency and the train of thought wanders. Tangentiality is defined by Andreasen [2] as replying in an irrelevant manner; it refers only to immediate replies to questions (stimulus-response mode) and not to transitions in spontaneous speech. Tangentiality is theoretically distinguished from several other disorders such as: derailment, in which the errors are similar to tangentiality but they occur in the spontaneous conversational mode; poverty of content of speech, where the speech is adequate in amount but conveys little information; distractible speech, where inappropriate changes of topic only occur in response to external environmental stimuli; circumstantial speech, where the speech is indirect or delayed in reaching the goal, but the goal is eventu-

A similar methodological heterogeneity has been described for TS, within the perspective of discourse analysis [7].

Toward controlling this source of vari-

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193

extremely variable conceptions and approaches.<sup>1</sup>

tual integration) of previous concepts on the matter is required.

sphere communication dysfunctions ([12–16], also see below).

ity and/or relevance are involved.

ally reached, etc. [2].

1

study approach.

discourse.

Currently, there is growing interest in the neurobiology of language beyond single words or short phrases [3–5] and, consequently, beyond aphasia. Aside from those basic studies, and going to the clinical practice, health professionals are often faced with patients (without aphasia) who cannot adequately explain a certain topic, for example, the reason for consultation. This may be a non-trivial problem. The impossibility of finding or pondering the proper verbal information to narrate an event (even when the most basic linguistic elements to construct the narrative are preserved) may be related to illness. The identification and causes of such impossibility require suitable evaluations as well as better definitions.

Excessive speech and incoherent or disorganized speech involve two different systems of classification. However, they are commonly linked. The terms logorrhoea; verbosity; tachyphemia; pressured speech; cluttered speech; disorders of speech, fluency, communication or language in general; circumstantial speech; tangential speech (TS); disconnected speech; flight of ideas; formal thought disorder; 'word salad'; loss of goal; loss of topic; etc., are ambiguously defined in the literature. The definitions change notably throughout the different disciplines or authors involved. There are even some methodological problems to differentiate, for example, a lot of speech, which may be just a style of speech, from logorrhoea, which includes failures in the quality and consistency of speech; these problems may become evident when tests of fluency are used as indicators of logorrhoea [6].

In order to increase understanding on the matter, it is necessary to study each of those terms or constructs more systematically, from different perspectives. In particular, the use of comprehensive approaches in which pure language impairments are integrated with the rest of the cognitive functions is a necessary endeavor. Concurrently, and since the newest approaches in neuroimaging, for example, tend to study restricted language tasks and brain regions, the complement among different perspectives is for this reason doubly advisable.

There is a lack of study aimed at systematically analyzing TS in order to delimit and organize its conceptual and methodological basis. In this work, TS is attempted to be studied as pure language impairment because losing the focus or topic of the conversation has been found to be a common factor among several manifestations of irrelevant or incoherent speech. Besides, the concept of TS in itself links two attributes of the narrative: its content and quality (the 'what') with its organization and consistency (the 'how').

This study may represent the first attempt in the scope to generate hypotheses about a feature that usually has been explored as part of the larger attribute of pragmatics, with extremely variable conceptions and approaches.<sup>1</sup> Toward controlling this source of variability, and taking into account that discourse processing has been considered a typical skill associated with pragmatics, some of the measures which have been previously reported as valid indicators of discourse processing (see, e.g., [8–10]), were included in the present study approach.

listener. Ferstl et al. [1] affirm that language processing in context requires more than merely comprehending words and sentences: important processes such as inferences for bridging successive utterances, the use of background knowledge, discourse context and pragmatic interpretations need to be considered. Besides, the study of language processing in context also requires the analysis of its behavioral or expressive mechanisms, in particular, the presence of failures in goal-directed speech. Considering the method of analysis on these mechanisms, it is probable that the presence of failures in the quality and consistency of the discourse can be screened with a single (but comprehensive) measure, thus avoiding fragmentation into multiple variables, as previously considered in the

Currently, there is growing interest in the neurobiology of language beyond single words or short phrases [3–5] and, consequently, beyond aphasia. Aside from those basic studies, and going to the clinical practice, health professionals are often faced with patients (without aphasia) who cannot adequately explain a certain topic, for example, the reason for consultation. This may be a non-trivial problem. The impossibility of finding or pondering the proper verbal information to narrate an event (even when the most basic linguistic elements to construct the narrative are preserved) may be related to illness. The identification and causes of such impossibility require suitable evaluations as well as bet-

Excessive speech and incoherent or disorganized speech involve two different systems of classification. However, they are commonly linked. The terms logorrhoea; verbosity; tachyphemia; pressured speech; cluttered speech; disorders of speech, fluency, communication or language in general; circumstantial speech; tangential speech (TS); disconnected speech; flight of ideas; formal thought disorder; 'word salad'; loss of goal; loss of topic; etc., are ambiguously defined in the literature. The definitions change notably throughout the different disciplines or authors involved. There are even some methodological problems to differentiate, for example, a lot of speech, which may be just a style of speech, from logorrhoea, which includes failures in the quality and consistency of speech; these problems may become evident when

In order to increase understanding on the matter, it is necessary to study each of those terms or constructs more systematically, from different perspectives. In particular, the use of comprehensive approaches in which pure language impairments are integrated with the rest of the cognitive functions is a necessary endeavor. Concurrently, and since the newest approaches in neuroimaging, for example, tend to study restricted language tasks and brain regions, the complement among different perspectives is for this reason doubly

There is a lack of study aimed at systematically analyzing TS in order to delimit and organize its conceptual and methodological basis. In this work, TS is attempted to be studied as pure language impairment because losing the focus or topic of the conversation has been found to be a common factor among several manifestations of irrelevant or incoherent speech. Besides, the concept of TS in itself links two attributes of the narrative: its content and quality (the

field of communication disorders (see, e.g., [2]).

tests of fluency are used as indicators of logorrhoea [6].

'what') with its organization and consistency (the 'how').

ter definitions.

192 Gerontology

advisable.

The evaluation of spontaneous speech is a crucial step in any neuropsychological assessment to detect aphasia, but not to detect TS. Probably this is so because a simple easy-to-administer scale for measuring this comprehensive behavior has not been designed yet, particularly in clinical settings and for screening purposes. To design such a TS scale, the analysis (and eventual integration) of previous concepts on the matter is required.

Harvey and Bowie [11] described two types of disturbances in the production of goaldirected speech as common symptoms in schizophrenia: verbal underproductivity and disconnected speech. The first is characterized by a reduction in the amount of speech or in the breadth of information; the second, by illogical or tangential connections between words or sentences as a result of which the speaker often fails to return to the goal of the discourse.

In the field of brain injury, unlike the above described classification, disconnected or underproductive discourses could in principle suggest either delirium (involving disturbance/ clouding of consciousness) or aphasia (involving lack/impairment of fluency or naming). Discarding delirium and aphasia such types of verbal symptoms may mimic psychiatric ones which, incidentally, have been considered for some authors manifestations of right hemisphere communication dysfunctions ([12–16], also see below).

Some of the neuropsychiatric constructs that have been cited together with TS are quite similar in many respects to TS, in particular when the attributes of coherence, consistency, stability and/or relevance are involved.

Tanner [17] stated that logorrhea is a garrulous and incoherent talking; the speech is rambling and has no point or conclusion; words are not connected semantically. The author also states that TS lacks of continuity and consistency and the train of thought wanders. Tangentiality is defined by Andreasen [2] as replying in an irrelevant manner; it refers only to immediate replies to questions (stimulus-response mode) and not to transitions in spontaneous speech. Tangentiality is theoretically distinguished from several other disorders such as: derailment, in which the errors are similar to tangentiality but they occur in the spontaneous conversational mode; poverty of content of speech, where the speech is adequate in amount but conveys little information; distractible speech, where inappropriate changes of topic only occur in response to external environmental stimuli; circumstantial speech, where the speech is indirect or delayed in reaching the goal, but the goal is eventually reached, etc. [2].

<sup>1</sup> A similar methodological heterogeneity has been described for TS, within the perspective of discourse analysis [7].

In the present work, and trying to achieve a unified construct, previous studies on TS as well as on disconnected speech, logorrhoea, circumstantial speech and any other dysfunction which affect the quality and consistency of information in the topic of the discourse were reviewed.

to be analyzed. However, the presence of failures in the processing of this feature, along with its neurological, cognitive and behavioral implications has not been elucidated yet. Neuropsychologically speaking, and as stated by Zanini et al. [39], the strong dichotomy of denotative versus connotative language, as processed by the left versus right hemispheres, respectively, has been recently challenged. Interestingly, some of the supposed abilities of the right hemisphere are nowadays separately analyzed in studies of social cognition, emotional connotation, valence, neuropragmatics, mentalizing, communication and narrative processing, among other processes [1, 3–5, 8, 40–48]. Such studies usually describe extended brain networks and bilateral involvement in their communication or language

Neurocognitive Implications of Tangential Speech in Patients with Focal Brain Damage

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The influence of the left hemisphere and the non-frontal lobes on TS might be indirectly inferred from those studies which, to date, have mainly involved healthy participants (HP) and language comprehension tasks. Nevertheless, when a language expression task (i.e., narrative production) was additionally evaluated in two neurofunctional studies with healthy participants [8, 40], Awad et al. [40] observed a common bilateral functional system, predominantly left lateralized, for both narrative comprehension and production. This functional system was most apparent in the left anterior temporal neocortex and the left temporal-occipital-parietal junction. As well, while the left and right hippocampus and adjacent inferior temporal cortex were active during speech comprehension, activity was reduced during speech production. AbdulSabur et al. [8] observed that the language system was integrated with regions that support other cognitive and sensorimotor domains, that is, they observed that, in addition to traditional language areas (e.g., left inferior frontal and posterior middle temporal gyri), both narrative production and comprehension engaged regions associated with mentalizing and situation model construction, as well as premotor areas. These authors reported strong associations between language areas and the superior and middle temporal gyri during both tasks. However, only during narrative production were the language-related regions connected to cortical and subcortical motor regions. AbdulSabur et al. [8] reported marked bilateral involvement for narrative comprehension alone (including right hemisphere homologs of perisylvian language areas), and predominantly left lateralized (and anterior) involvement for

Complementary research exploring the relationship between patients with focal brain lesions and language expression tasks, excluding aphasia, is necessary. TS has been poorly studied in patients with focal brain lesions, especially in patients with left hemisphere damage and in patients differentiated by frontal and non-frontal lobe damage. A comprehensive neuropsychological study of goal-directed speech is necessary in the scope, not only to help elucidate the TS neuroanatomical correlates but also the TS cognitive and behavioral nature. This research aims to take a step forward in the study of narrative processing, by evaluating TS in a sample that helps detect this deficit when it is neurogenic and recently manifested. Due to the lack of clear antecedents on the matter, the main objective for the present study was to explore the relationship between TS, secondary to focal brain injury, and neuropsychological

models.

narrative production alone.

and neuroanatomical variables.

Disconnected speech, logorrhoea and TS have been associated with psychiatric and/or cognitive disorders not neurologically lateralized [17–27], including schizophrenia,<sup>2</sup> dementia, mania, autism, semantic pragmatic disorder, attention-deficit hyperactivity disorder and traumatic brain injury.

Concerning the neuroanatomical bases of disconnected speech, logorrhoea and TS, ambiguous findings have been reported when using the lesion-based approach. As a rule, these reports do not clearly demonstrate the double dissociation between, for example, the left and the right hemispheres, and the frontal lobe and the rest of the lobes [12, 28–34]. Considering just TS, and excluding subcortical structures, Marini [33] supports the hypothesis that there is a major involvement of frontal right hemispheric areas to the process of organization of information in a narrative discourse: the individuals with right hemisphere damage produced descriptions with normal levels of microlinguistic processing but with more tangential errors and conceptually incongruent utterances, that is, with more impairments in macrolinguistic processing. Within this framework, the right hemisphere has been associated with the ability to correctly communicate prosodic, discourse and pragmatic aspects of language, including topic maintenance [29]. On the contrary, the involvement of the left hemisphere on TS has rarely been reported. Ferstl et al. [35] state that damage to frontal areas has been associated with nonaphasic language disturbances in which word and sentence level processes remain largely intact but text level processes are impaired. These authors studied several sites of lesions, including non-frontal ones, and analyzed text comprehension in nonaphasic patients. Ferstl et al. [35] observed that patients with leftfrontal or bilateral frontal lesions cannot make use of instructions which require a change of perspective for recalling a story; besides, left-frontal damage leads to an impairment of goal-directed text-processing skills. Despite such specific finding, and under the lesionbased approach, the involvement of the left hemisphere and the non-frontal lobes on TS is scarce or unclear.

The dissociation between the left and the right hemisphere has been more frequently studied, and the results are contradictory, when the so-called pragmatic and/or emotional abilities of the right hemisphere (considered as a whole) were analyzed [10, 14, 36–39]. Taking into account these specific abilities of the right hemisphere, the quality and consistency of information in the topic of the discourse has always been an essential feature

<sup>2</sup> In the field of schizophrenia, Holshausen et al. [23] exclude the indicator of poverty of content [2] from the concept of disconnected speech. However, in the present study it is assumed that if a patient speaks fluently but he/she conveys little information, then such information is irrelevant; additionally, if the information conveyed is superficial or indirect, as in the case of circumstantial speech, such information is also irrelevant. Holshausen et al. [23] did include the indicator of circumstantial speech [2] within the concept of disconnected speech. However, the supposed property of circumstantial speech by which the goal of the conversation is 'eventually reached' [2] is not here assumed as a true event; instead, the degree by which that goal is actually reached is analyzed.

to be analyzed. However, the presence of failures in the processing of this feature, along with its neurological, cognitive and behavioral implications has not been elucidated yet. Neuropsychologically speaking, and as stated by Zanini et al. [39], the strong dichotomy of denotative versus connotative language, as processed by the left versus right hemispheres, respectively, has been recently challenged. Interestingly, some of the supposed abilities of the right hemisphere are nowadays separately analyzed in studies of social cognition, emotional connotation, valence, neuropragmatics, mentalizing, communication and narrative processing, among other processes [1, 3–5, 8, 40–48]. Such studies usually describe extended brain networks and bilateral involvement in their communication or language models.

In the present work, and trying to achieve a unified construct, previous studies on TS as well as on disconnected speech, logorrhoea, circumstantial speech and any other dysfunction which affect the quality and consistency of information in the topic of the discourse were

Disconnected speech, logorrhoea and TS have been associated with psychiatric and/or cog-

mania, autism, semantic pragmatic disorder, attention-deficit hyperactivity disorder and

Concerning the neuroanatomical bases of disconnected speech, logorrhoea and TS, ambiguous findings have been reported when using the lesion-based approach. As a rule, these reports do not clearly demonstrate the double dissociation between, for example, the left and the right hemispheres, and the frontal lobe and the rest of the lobes [12, 28–34]. Considering just TS, and excluding subcortical structures, Marini [33] supports the hypothesis that there is a major involvement of frontal right hemispheric areas to the process of organization of information in a narrative discourse: the individuals with right hemisphere damage produced descriptions with normal levels of microlinguistic processing but with more tangential errors and conceptually incongruent utterances, that is, with more impairments in macrolinguistic processing. Within this framework, the right hemisphere has been associated with the ability to correctly communicate prosodic, discourse and pragmatic aspects of language, including topic maintenance [29]. On the contrary, the involvement of the left hemisphere on TS has rarely been reported. Ferstl et al. [35] state that damage to frontal areas has been associated with nonaphasic language disturbances in which word and sentence level processes remain largely intact but text level processes are impaired. These authors studied several sites of lesions, including non-frontal ones, and analyzed text comprehension in nonaphasic patients. Ferstl et al. [35] observed that patients with leftfrontal or bilateral frontal lesions cannot make use of instructions which require a change of perspective for recalling a story; besides, left-frontal damage leads to an impairment of goal-directed text-processing skills. Despite such specific finding, and under the lesionbased approach, the involvement of the left hemisphere and the non-frontal lobes on TS is

The dissociation between the left and the right hemisphere has been more frequently studied, and the results are contradictory, when the so-called pragmatic and/or emotional abilities of the right hemisphere (considered as a whole) were analyzed [10, 14, 36–39]. Taking into account these specific abilities of the right hemisphere, the quality and consistency of information in the topic of the discourse has always been an essential feature

In the field of schizophrenia, Holshausen et al. [23] exclude the indicator of poverty of content [2] from the concept of disconnected speech. However, in the present study it is assumed that if a patient speaks fluently but he/she conveys little information, then such information is irrelevant; additionally, if the information conveyed is superficial or indirect, as in the case of circumstantial speech, such information is also irrelevant. Holshausen et al. [23] did include the indicator of circumstantial speech [2] within the concept of disconnected speech. However, the supposed property of circumstantial speech by which the goal of the conversation is 'eventually reached' [2] is not here assumed as a true event; instead,

dementia,

nitive disorders not neurologically lateralized [17–27], including schizophrenia,<sup>2</sup>

reviewed.

194 Gerontology

traumatic brain injury.

scarce or unclear.

the degree by which that goal is actually reached is analyzed.

2

The influence of the left hemisphere and the non-frontal lobes on TS might be indirectly inferred from those studies which, to date, have mainly involved healthy participants (HP) and language comprehension tasks. Nevertheless, when a language expression task (i.e., narrative production) was additionally evaluated in two neurofunctional studies with healthy participants [8, 40], Awad et al. [40] observed a common bilateral functional system, predominantly left lateralized, for both narrative comprehension and production. This functional system was most apparent in the left anterior temporal neocortex and the left temporal-occipital-parietal junction. As well, while the left and right hippocampus and adjacent inferior temporal cortex were active during speech comprehension, activity was reduced during speech production. AbdulSabur et al. [8] observed that the language system was integrated with regions that support other cognitive and sensorimotor domains, that is, they observed that, in addition to traditional language areas (e.g., left inferior frontal and posterior middle temporal gyri), both narrative production and comprehension engaged regions associated with mentalizing and situation model construction, as well as premotor areas. These authors reported strong associations between language areas and the superior and middle temporal gyri during both tasks. However, only during narrative production were the language-related regions connected to cortical and subcortical motor regions. AbdulSabur et al. [8] reported marked bilateral involvement for narrative comprehension alone (including right hemisphere homologs of perisylvian language areas), and predominantly left lateralized (and anterior) involvement for narrative production alone.

Complementary research exploring the relationship between patients with focal brain lesions and language expression tasks, excluding aphasia, is necessary. TS has been poorly studied in patients with focal brain lesions, especially in patients with left hemisphere damage and in patients differentiated by frontal and non-frontal lobe damage. A comprehensive neuropsychological study of goal-directed speech is necessary in the scope, not only to help elucidate the TS neuroanatomical correlates but also the TS cognitive and behavioral nature. This research aims to take a step forward in the study of narrative processing, by evaluating TS in a sample that helps detect this deficit when it is neurogenic and recently manifested. Due to the lack of clear antecedents on the matter, the main objective for the present study was to explore the relationship between TS, secondary to focal brain injury, and neuropsychological and neuroanatomical variables.

The present study is part of a bigger research project which aims at developing efficient tests, that is, brief and/or easy to apply neuropsychological techniques without neglecting the goals of accuracy and validity (see, e.g., [49–51]). Since theory and validity are interlaced, it is expected that the present data are not only useful to hypothesize about the bases of TS, but also to explore the viability, validity and reliability of the present scale to assess TS in a natural situation, by the bedside of the patient.

cancelation (verbal auditory selective and sustained attention: omission and commission E); (5) figure discrimination (triangle) by visual cancelation [nonverbal visual selective and sustained attention: correct responses (CR) as well as errors and time (E&T)]; (6) direct and reverse serial order (months forward and backwards: E&T); (7) spatial memory (five hidden objects: accuracy (remembered objects and places) as well as four different types of E); (8) copy of alternating or repetitive graph series; (9) copy and naming (written response) of simple figures; (10) constructional praxia (cube and clock drawing in response to commands: CR and T); (11) syntax-complex verbal comprehension; (12) verbal auditory attention span (digits: forward and backwards); (13) writing abilities such as writing one verbal automatism (the name), writing by copying and by dictation and writing-legibility; (14) written verbal fluency [quantity: number of words, quality: syntactic complexity, legibility: overall score and legibility regardless of quantity (average score per word)]; (15) written arithmetic operations; (16) mental calculations (subtracting serial sevens: CR and T); (17) oral verbal fluency (number of words beginning with 'F'); (18) reading (a story): oral expression and abstraction/comprehension; (19) visual memory: face recognition; (20) visual memory: retrieval of a complex figure; (21) graphesthesia; (22) finger recognition; (23) a delayed story recall (spontaneous and cued, using two indicators: the interviewer's global impression during administration, and a standardized and detailed scoring of 25 passages after administration); (24) the paired-associate word learning, which included three trials and a delayed recall of easy and hard pairs and (25) semantic verbal memory/naming by picture confrontation. [Note: In general, accuracy (CR) was assessed unless otherwise indicated by E, T, and/or E&T.] The tasks of the battery related with DP were complex verbal comprehension (i.e., syntax-complex verbal comprehension and story comprehension) in addition to storytelling [i.e., a delayed story recall (spontaneous and cued)]. The tasks of the battery related with fluency were written verbal fluency (quantity: number of words) and oral verbal fluency (number of words beginning with 'F'). Details of test administration and

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The emergence of the following disorders as a consequence of brain injury as reported by the caregiver during the initial interview were also registered (scale range: 0–3): sensory deficits; motor deficits; perceptual-cognitive disorders (i.e., difficulty in recognizing known persons, places, moments or objects, independently of sensory acuity); sleeping disorders (i.e., insomnia, somnolence during the day, etc.); language disorders (i.e., paraphasias, anomies, echolalia, intrusions, reduced verbal comprehension or fluency, dysarthria, etc.); behavioral disorders (i.e., abnormal responses, anxiety, irritability, depression, lack of sphincter control, difficulty in organizing action, changes of personality, etc.); and thought disturbances (i.e., hallucinations, delusions, loss of sense of reality, dissociative symptoms, etc.). The presence

Some complementary behavioral observations, which are usually evaluated during the administration of the comprehensive battery were also analyzed: the behavioral observations computed in this study were: degree of cooperation (0–3, i.e., absent: 0, very poor: 1, poor: 2, good: 3); emotional state (−1 to 1, i.e., inhibited: −1, normal: 0, excited: 1); disability awareness (0–3,

scores are explained elsewhere [49–56].

of seizures was also registered.

In summary, the present study aimed to explore, in patients with focal brain injuries, if TS is associated with cognitive, emotional or behavioral impairments and with specific sites of brain injury. Complementarily, the present study aimed to explore if a hypothetical pattern of neuropsychological and/or neuroanatomical impairments can be identified for TS as well as if reliability and validity indices can be obtained for the present TS screening scale.

In view of the reviewed, and in an attempt to delimit the conceptual definition of TS, only communication dysfunctions which affect the quality and consistency of information in the topic of the discourse, without affecting the most basic resources to carry out such discourse, were considered. More specifically, when: (a) the deficit was secondary to brain injury, (b) the patient was alert, without aphasia, without psychiatric history and without TS history and (c) according to the conditions which were expressed in the first paragraph of this work, the topic of the conversation was missing (i.e., the topic was irrelevant to the interview situation, or it was not well preserved or focused during the interaction) the resulting speech was defined as tangential.

In view of the exploratory nature of the study, a comprehensive neuropsychological battery was administered because all the battery tests and subtests were in principle considered potential factors for explaining TS. However, and bearing in mind that the tasks of narrative comprehension, memory and production have been previously recognized as valid measures of discourse processing (DP) [8–10], they were specially evaluated. Considering that tests of fluency have been used as indicators of logorrhoea [6], and that logorrhoea includes failures in the quality and consistency of speech, the performance in tasks of spoken and written verbal fluency were also evaluated.
