Voice self-assessment in individuals with Parkinson's Disease as compared to general voice disorders.

BACKGROUND: Individuals with Parkinson's Disease (IwPD) often fail to adjust their voice in different situations, without awareness of this limitation. Clinicians use self-report questionnaires that are typically designed for individuals with General Voice Disorders (GVD) in the vocal assessment of IwPD. However, these instruments may not consider that IwPD have a reduced self-perception of their vocal deficits. This study aimed to compare self-reported vocal symptoms and voice loudness between IwPD and GVD. METHODS: 28 IwPD and 26 with GVD completed the Voice Symptom Scale (VoiSS) questionnaire to evaluate their voice self-perception. Vocal loudness (dB) was also assessed. Univariate and multivariate analyses were used to compare the outcomes from these measures between the two groups. Principal Component Analysis and Hierarchical Clustering Analysis were applied to explore data patterns related to voice symptoms. RESULTS: IwPD reported significantly fewer vocal symptoms than those with GVD in all VoiSS questionnaire domains. Multivariate principal component analysis found no significant correlations between VoiSS scores and participant similarities in voice measures. Despite experiencing hypophonia, IwPD scored lower in all VoiSS domains but still fell in the healthy voice range. Hierarchical Clustering Analysis grouped participants into three distinct categories, primarily based on age, vocal loudness, and VoiSS domain scores, distinguishing between PD and GVD individuals. CONCLUSIONS: IwPD reported fewer vocal symptoms than GVD. The voice self-assessment seems to be unreliable to assess vocal symptoms in IwPD, at least regarding loudness. New self-report instruments tailored to PD individuals are needed due to their particular voice characteristics.

Individual Differences in Chemosensory Perception Amongst Cancer Patients Undergoing Chemotherapy: A Narrative Review.

Chemotherapy is an aggressive form of treatment for cancer and its toxicity directly affects the eating behavior of many patients, usually by adversely affecting their sense of smell and/or taste. These sensory alterations often lead to serious nutritional deficiencies that can jeopardize the patient's recovery, and even continue to affect their lives once treatment has terminated. Importantly, however, not all patients suffer from such alterations to their chemical senses; and those who do, do not necessarily describe the side effects in quite the same way, nor suffer from them with equal intensity. The origin of these individual differences between cancer patients undergoing chemotherapy treatment has not, as yet, been studied in detail. This review is therefore designed to encourage future research that can help to address the perceptual/sensory problems (and the consequent malnutrition) identified amongst this group of patients in a more customized/personalized manner. In particular, by providing an overview of the possible causes of these large individual differences that have been reported in the literature. For this reason, in addition to the narrative bibliographic review, several possible strategies that could help to improve the chemosensory perception of food are proposed.

Perceptual association enhances intersensory temporal precision.

The brain is able to extract associative regularities between stimuli and readjust the perceived timing of correlated sensory signals. In order to elucidate whether these two mechanisms interact with each other or not, we exposed participants to two different visual stimuli (a circle and a triangle) that appeared continuously and unpredictably, for 5min. While the circle always preceded the tone for 700ms, the triangle did not. Yet, the triangle could appear, by chance, before and after the tone, and between the circle and the tone. In two different test blocks, conducted before and after the 5-min exposure phase, participants performed simultaneity judgments regarding one of the visual stimuli (the circle or the triangle) and the exposed tone presented at different stimulus onset asynchronies. The results revealed that the precision at judging the temporal relation between the 'associated figure' (the circle) and the tone increased significantly after the 5-min exposure. This effect was not observed for the non-associated figure (the triangle) and occurred even when participants reported to be unaware of any association between the stimuli presented. This pattern of results indicates that the perceptual association between sensory signals can influence their subjective temporal processing.

Early detection of subtle motor dysfunction in cognitively normal subjects with amyloid-ß positivity.

Since the current neuropsychological assessments are not sensitive to subtle deficits that may be present in cognitively normal subjects with amyloid-ß positivity, more accurate and efficient measures are needed. Our aim was to investigate the presence of subtle motor deficits in this population and its relationship with cerebrospinal fluid (CSF) amyloid-ß levels. We adapted the Finger Tapping Task to measure tapping speed and intrasubject variability. Seventy-two right-handed participants completed the study. Subjects were divided into three groups according to their CSF biomarker profile: 37 control participants (negative CSF AD biomarkers, CTR), 20 cognitively normal subjects with amyloid-ß positivity (abnormal levels of CSF Aß42, Aß+) and 15 AD patients. All subjects underwent lumbar puncture for the CSF analysis, apolipoprotein E genotyping and completed the Finger Tapping Task, a neuropsychological battery and cardiovascular risk factor and physical activity assessments. An overall difference between groups was found both in tapping speed [F(2,66) = 19.37, p < .01] and in intrasubject variability [F(2,66) = 11.40, p < .01]. More specifically, the Aß+ group showed lower speed [F(1,52) = 5.33, p < .05] and greater intrasubject variability [F(1,52) = 8.48, p < .01] than the CTR group, and higher speed than the AD group [F(1,30) = 13.61, p < .01]. Speed (ß = .263, p < .05) and intrasubject variability (ß = -.558, p < .01) were significantly associated with CSF amyloid-ß levels. The present findings suggest that subtle motor difficulties can be detected in cognitively healthy subjects with amyloid-ß positivity and be related to CSF Aß42 levels. An accurate assessment of motor functions could help on identifying individuals at the earliest stage of the Alzheimer's continuum.

Vertical mapping of auditory loudness: loud is high, but quiet is not always low

Although the perceptual association between verticality and pitch has been widely studied, the link between loudness and verticality is not fully understood yet. While loud and quiet sounds are assumed to be equally associated crossmodally with spatial elevation, there are perceptual differences between the two types of sounds that may suggest the contrary. For example, loud sounds tend to generate greater activity, both behaviourally and neurally, than quiet sounds. Here we investigated whether this difference percolates into the crossmodal correspondence between loudness and verticality. In an initial phase, participants learned one-to-one arbitrary associations between two tones differing in loudness (82dB vs.56dB) and two coloured rectangles (blue vs. yellow). During the experimental phase, they were presented with the two-coloured stimuli (each one located above or below a central "departure" point) together with one of the two tones. Participants had to indicate which of the two-coloured rectangles corresponded to the previously-associated tone by moving a mouse cursor from the departure point towards the target. The results revealed that participants were significantly faster responding to the loud tone when the visual target was located above (congruent condition) than when the target was below the departure point (incongruent condition). For quiet tones, no differences were found between the congruent (quiet-down) and the incongruent (quiet-up) conditions. Overall, this pattern of results suggests that possible differences in the neural activity generated by loud and quiet sounds influence the extent to which loudness and spatial elevation share representational content

Aunque la asociación perceptiva entre la verticalidad y la frecuencia auditiva ha sido ampliamente estudiada, la relación entre la intensidad y la verticalidad sigue sin entenderse completamente. Mientras que se asume que los sonidos más y menos intensos están asociados de forma igual con la elevación espacial, existen diferencias perceptivas entre los dos tipos de sonidos que sugieren lo contrario. Por ejemplo, los sonidos más intensos tienden a generar más actividad, tanto en el aspecto conductual como neuronal, que los sonidos más flojos. En este estudio, investigamos si esta diferencia influye en la correspondencia transmodal entre la intensidad y la verticalidad. En una fase inicial, los participantes aprendieron asociaciones arbitrarias entre uno de dos tonos que diferían en intensidad (82dB vs.56 dB) y uno de dos rectángulos coloreados (azul vs. amarillo). Durante la fase experimental, se les presentaron los dos estímulos coloreados (cada uno de ellos localizado por encima o debajo de un punto central de partida), junto con uno de los dos tonos. Los participantes tenían que indicar cuál de los dos rectángulos coloreados correspondía al tono previamente asociado moviendo el cursor del ratón desde el punto de partida hasta el objetivo. Los resultados mostraron que los participantes fueron significativamente más rápidos cuando respondían al tono más intenso cuando el objetivo visual se situaba arriba (condición congruente) que cuando se situaba abajo (condición incongruente). Para los sonidos menos intensos no se observaron diferencias entre las condiciones congruente (flojo-abajo) e incongruente (flojo-arriba). En general, este patrón de resultados sugiere que las posibles diferencias en la actividad neuronal generadas por sonidos de mayor y menor intensidad influyen el grado en el que la intensidad y la elevación espacial comparten contenido representacional

Seeing music: The perception of melodic 'ups and downs' modulates the spatial processing of visual stimuli.

Musical melodies have "peaks" and "valleys". Although the vertical component of pitch and music is well-known, the mechanisms underlying its mental representation still remain elusive. We show evidence regarding the importance of previous experience with melodies for crossmodal interactions to emerge. The impact of these crossmodal interactions on other perceptual and attentional processes was also studied. Melodies including two tones with different frequency (e.g., E4 and D3) were repeatedly presented during the study. These melodies could either generate strong predictions (e.g., E4-D3-E4-D3-E4-[D3]) or not (e.g., E4-D3-E4-E4-D3-[?]). After the presentation of each melody, the participants had to judge the colour of a visual stimulus that appeared in a position that was, according to the traditional vertical connotations of pitch, either congruent (e.g., high-low-high-low-[up]), incongruent (high-low-high-low-[down]) or unpredicted with respect to the melody. Behavioural and electroencephalographic responses to the visual stimuli were obtained. Congruent visual stimuli elicited faster responses at the end of the experiment than at the beginning. Additionally, incongruent visual stimuli that broke the spatial prediction generated by the melody elicited larger P3b amplitudes (reflecting 'surprise' responses). Our results suggest that the passive (but repeated) exposure to melodies elicits spatial predictions that modulate the processing of other sensory events.

Does Language Influence the Vertical Representation of Auditory Pitch and Loudness?

Higher frequency and louder sounds are associated with higher positions whereas lower frequency and quieter sounds are associated with lower locations. In English, "high" and "low" are used to label pitch, loudness, and spatial verticality. By contrast, different words are preferentially used, in Catalan and Spanish, for pitch (high: "agut/agudo"; low: "greu/grave") and for loudness/verticality (high: "alt/alto"; low: "baix/bajo"). Thus, English and Catalan/Spanish differ in the spatial connotations for pitch. To analyze the influence of language on these crossmodal associations, a task was conducted in which English and Spanish/Catalan speakers had to judge whether a tone was higher or lower (in pitch or loudness) than a reference tone. The response buttons were located at crossmodally congruent or incongruent positions with respect to the probe tone. Crossmodal correspondences were evidenced in both language groups. However, English speakers showed greater effects for pitch, suggesting an influence of linguistic background.

Subtle visuomotor deficits and reduced benefit from practice in early treated phenylketonuria.

INTRODUCTION: Phenylketonuria (PKU) is a rare metabolic disease that causes slight-to-severe neurological symptoms. Slow performance has been observed in PKU but the influence of high-order (i.e., not purely motor) deficits and of temporary variations of the phenylalanine (Phe) level on this slowness has not been fully corroborated as yet. Response speed and the effect of motor practice during the performance of a visuomotor coordination task were measured, in a group of patients with early-treated phenylketonuria (ET PKU). METHOD: We compared the performance of a group of early-treated PKU patients with ages ranging from 11 to 25 years and a control group of healthy volunteers on a computerized visuomotor task. Participants performed rapid movements towards one of five response buttons, as indicated by a visual stimulus that could appear in five different positions on a computer screen. The results of our visuomotor task were correlated with neurobiological data (Phe levels) and with neuropsychological measures of motor (finger tapping) and executive functions (Stroop task). RESULTS: The ET PKU group showed slower responses than the control group. Furthermore, an absence of a practice effect (i.e., faster response times at the end of the study) was found in the PKU group but not in the control group. Our results also revealed that this absence of practice effect correlated with higher Phe levels on the testing day with respect to the average Phe level of the previous 12 months and, although weakly, with performance on the Stroop task. CONCLUSIONS: This pattern of results indicates slower visuomotor performance and a less beneficial effect of practice in ET PKU. The correlations found among our visuomotor measures, the same-day Phe level, and the Stroop test may reflect the negative effects of dopamine reduction in brain areas involved in motor control, selective attention, and learning.

Subtle visuomotor difficulties in preclinical Alzheimer's disease.

BACKGROUND: Individuals with preclinical Alzheimer's disease (Pre-AD) present nonimpaired cognition, as measured by standard neuropsychological tests. However, detecting subtle difficulties in cognitive functions may be necessary for an early diagnosis and intervention. OBJECTIVES: A new computer-based visuomotor coordination task (VMC) was developed to investigate the possible presence of early visuomotor difficulties in Pre-AD individuals. Associations between VMC task performance and AD biomarkers were studied. The influence of ApoE status on participants' performance was addressed, as well as the relationship between performance and subjective cognitive decline (SCD). METHODS: Sixty-six cognitively normal (CN) elders (19 Pre-AD and 47 control participants [CTR]) and 15 patients with AD performed the VMC task, which consisted in executing visually guided goal-directed movements that required the coordination of the visual and motor systems. All participants underwent ApoE analysis and lumbar puncture. CN participants also completed an extensive standard neuropsychological battery. RESULTS: Despite presenting normal cognition in standard tests, Pre-AD participants exhibited higher response times (RTs) to complete the VMC task than CTR (p < .01). Besides, patients with AD showed higher RTs than CTR (p < .001) and Pre-AD (p < .05), and more errors than CTR (p < .005). RTs in ApoE4 carriers were higher than that observed in ApoE4 noncarriers (p < .01). In CN individuals, RTs were related to amyloid ß-protein 42 (AB42) biomarker (p < .01) and informant-rated SCD (p < .01). CONCLUSIONS: The VMC task is able to discriminate Pre-AD from CTR individuals. Moreover, VMC results are associated with AB42 levels in CN individuals, suggesting that visuomotor dysfunction may be a sensitive marker of Pre-AD.

Mixing apples with oranges: Visual attention deficits in schizophrenia.

BACKGROUND & OBJECTIVES: Patients with schizophrenia usually present cognitive deficits. We investigated possible anomalies at filtering out irrelevant visual information in this psychiatric disorder. Associations between these anomalies and positive and/or negative symptomatology were also addressed. METHODS: A group of individuals with schizophrenia and a control group of healthy adults performed a Garner task. In Experiment 1, participants had to rapidly classify visual stimuli according to their colour while ignoring their shape. These two perceptual dimensions are reported to be "separable" by visual selective attention. In Experiment 2, participants classified the width of other visual stimuli while trying to ignore their height. These two visual dimensions are considered as being "integral" and cannot be attended separately. RESULTS: While healthy perceivers were, in Experiment 1, able to exclusively respond to colour, an irrelevant variation in shape increased colour-based reaction times (RTs) in the group of patients. In Experiment 2, RTs when classifying width increased in both groups as a consequence of perceiving a variation in the irrelevant dimension (height). However, this interfering effect was larger in the group of schizophrenic patients than in the control group. Further analyses revealed that these alterations in filtering out irrelevant visual information correlated with positive symptoms in PANSS scale. LIMITATIONS: A possible limitation of the study is the relatively small sample. CONCLUSIONS: Our findings suggest the presence of attention deficits in filtering out irrelevant visual information in schizophrenia that could be related to positive symptomatology.

How big is this sound? Crossmodal association between pitch and size in infants.

We examined 4- and 6-month-old infants' sensitivity to the perceptual association between pitch and object size. Crossmodal correspondence effects were observed in 6-month-old infants but not in younger infants, suggesting that experience and/or further maturation is needed to fully develop this crossmodal association.

Discriminating speech rhythms in audition, vision, and touch.

We investigated the extent to which people can discriminate between languages on the basis of their characteristic temporal, rhythmic information, and the extent to which this ability generalizes across sensory modalities. We used rhythmical patterns derived from the alternation of vowels and consonants in English and Japanese, presented in audition, vision, both audition and vision at the same time, or touch. Experiment 1 confirmed that discrimination is possible on the basis of auditory rhythmic patterns, and extended it to the case of vision, using 'aperture-close' mouth movements of a schematic face. In Experiment 2, language discrimination was demonstrated using visual and auditory materials that did not resemble spoken articulation. In a combined analysis including data from Experiments 1 and 2, a beneficial effect was also found when the auditory rhythmic information was available to participants. Despite the fact that discrimination could be achieved using vision alone, auditory performance was nevertheless better. In a final experiment, we demonstrate that the rhythm of speech can also be discriminated successfully by means of vibrotactile patterns delivered to the fingertip. The results of the present study therefore demonstrate that discrimination between language's syllabic rhythmic patterns is possible on the basis of visual and tactile displays.

Age-related sensitive periods influence visual language discrimination in adults.

Adults as well as infants have the capacity to discriminate languages based on visual speech alone. Here, we investigated whether adults' ability to discriminate languages based on visual speech cues is influenced by the age of language acquisition. Adult participants who had all learned English (as a first or second language) but did not speak French were shown faces of bilingual (French/English) speakers silently reciting sentences in either language. Using only visual speech information, adults who had learned English from birth or as a second language before the age of 6 could discriminate between French and English significantly better than chance. However, adults who had learned English as a second language after age 6 failed to discriminate these two languages, suggesting that early childhood exposure is crucial for using relevant visual speech information to separate languages visually. These findings raise the possibility that lowered sensitivity to non-native visual speech cues may contribute to the difficulties encountered when learning a new language in adulthood.

Realigning thunder and lightning: temporal adaptation to spatiotemporally distant events.

The brain is able to realign asynchronous signals that approximately coincide in both space and time. Given that many experience-based links between visual and auditory stimuli are established in the absence of spatiotemporal proximity, we investigated whether or not temporal realignment arises in these conditions. Participants received a 3-min exposure to visual and auditory stimuli that were separated by 706 ms and appeared either from the same (Experiment 1) or from different spatial positions (Experiment 2). A simultaneity judgment task (SJ) was administered right afterwards. Temporal realignment between vision and audition was observed, in both Experiment 1 and 2, when comparing the participants' SJs after this exposure phase with those obtained after a baseline exposure to audiovisual synchrony. However, this effect was present only when the visual stimuli preceded the auditory stimuli during the exposure to asynchrony. A similar pattern of results (temporal realignment after exposure to visual-leading asynchrony but not after exposure to auditory-leading asynchrony) was obtained using temporal order judgments (TOJs) instead of SJs (Experiment 3). Taken together, these results suggest that temporal recalibration still occurs for visual and auditory stimuli that fall clearly outside the so-called temporal window for multisensory integration and appear from different spatial positions. This temporal realignment may be modulated by long-term experience with the kind of asynchrony (vision-leading) that we most frequently encounter in the outside world (e.g., while perceiving distant events).

Short-term experience increases infants' sensitivity to audiovisual asynchrony.

The present study explored the effects of short-term experience with audiovisual asynchronous stimuli in 6-month-old infants. Results revealed that, in contrast with adults (usually showing temporal recalibration under similar circumstances), a brief exposure to asynchrony increased infants' perceptual sensitivity to audiovisual synchrony.

Temporal adaptation to audiovisual asynchrony generalizes across different sound frequencies.

The human brain exhibits a highly adaptive ability to reduce natural asynchronies between visual and auditory signals. Even though this mechanism robustly modulates the subsequent perception of sounds and visual stimuli, it is still unclear how such a temporal realignment is attained. In the present study, we investigated whether or not temporal adaptation generalizes across different auditory frequencies. In a first exposure phase, participants adapted to a fixed 220-ms audiovisual asynchrony or else to synchrony for 3 min. In a second phase, the participants performed simultaneity judgments (SJs) regarding pairs of audiovisual stimuli that were presented at different stimulus onset asynchronies (SOAs) and included either the same tone as in the exposure phase (a 250 Hz beep), another low-pitched beep (300 Hz), or a high-pitched beep (2500 Hz). Temporal realignment was always observed (when comparing SJ performance after exposure to asynchrony vs. synchrony), regardless of the frequency of the sound tested. This suggests that temporal recalibration influences the audiovisual perception of sounds in a frequency non-specific manner and may imply the participation of non-primary perceptual areas of the brain that are not constrained by certain physical features such as sound frequency.

El sistema perceptivo: esa pequeña máquina del tiempo / The perceptual system: That little time-machine

Diversas circunstancias de carácter físico (por ejemplo, el hecho de que la luz y el sonido no viajen a la misma velocidad) y/o fisiológico (la señal auditiva tarda menos que la señal visual en llegar a la corteza cerebral primaria) pueden originar ciertos desajustes temporales entre la información sensorial sobre un mismo evento. Teniendo en cuenta la enorme cantidad de estímulos que nos invade en ciertos momentos, el poder reagrupar las señales sensoriales que pertenecen a un mismo evento, a pesar de la asincronía, puede resultar un mecanismo adaptativo de primer orden. El cerebro humano parece capaz, en definitiva, de hacer reaparecer la simultaneidad allí donde no la hay. ¿Cómo lo logra? Dos fenómenos recientemente descubiertos –la ventriloquia temporal (según la cual, la aparición de un estímulo puede influir en el momento en el que percibimos otros) y la recalibración temporal (a través de la cual, el cerebro realinea las señales asincrónicas que provienen de distintas modalidades sensoriales)– atestiguan que la forma en que lo hace es mucho más activa y flexible de lo que hasta ahora se había imaginado (AU)

Various physical circumstances (for instance, the fact that light and sound do not travel at the same speed) and/or physiological factors (such as the fact that auditory signals are initially processed more rapidly than visual signals) give rise to small asynchronies between sensory signals pertaining to a specific multisensory event. Considering the large amount of sensory stimulation that bombards our senses at any given time, being able to regroup sensory signals that belong to the same event (even if they arrive asynchronously) can be highly adaptative. Indeed, the human brain is by-and-large able to maintain a simultaneous and coherent perception of the proximal events that occur in the environment. How is this achieved? Two recently discovered phenomena –temporal ventriloquism (where the presence of a stimulus in one modality influences the perceived time of occurrence of a stimulus in another modality) and temporal recalibration (where the brain realigns asynchronous signals from different sensory modalities)– confirm that the way in which the human brain maintains synchrony is more active and flexible than previously thought (AU)

Perception of audiovisual speech synchrony for native and non-native language.

To what extent does our prior experience with the correspondence between audiovisual stimuli influence how we subsequently bind them? We addressed this question by testing English and Spanish speakers (having little prior experience of Spanish and English, respectively) on a crossmodal simultaneity judgment (SJ) task with English or Spanish spoken sentences. The results revealed that the visual speech stream had to lead the auditory speech stream by a significantly larger interval in the participants' native language than in the non-native language for simultaneity to be perceived. Critically, the difference in temporal processing between perceiving native vs. non-native language tends to disappear as the amount of experience with the non-native language increases. We propose that this modulation of multisensory temporal processing as a function of prior experience is a consequence of the constraining role that visual information plays in the temporal alignment of audiovisual speech signals.

Adaptation to audiovisual asynchrony modulates the speeded detection of sound.

The brain adapts to asynchronous audiovisual signals by reducing the subjective temporal lag between them. However, it is currently unclear which sensory signal (visual or auditory) shifts toward the other. According to the idea that the auditory system codes temporal information more precisely than the visual system, one should expect to find some temporal shift of vision toward audition (as in the temporal ventriloquism effect) as a result of adaptation to asynchronous audiovisual signals. Given that visual information gives a more exact estimate of the time of occurrence of distal events than auditory information (due to the fact that the time of arrival of visual information regarding an external event is always closer to the time at which this event occurred), the opposite result could also be expected. Here, we demonstrate that participants' speeded reaction times (RTs) to auditory (but, critically, not visual) stimuli are altered following adaptation to asynchronous audiovisual stimuli. After receiving "baseline" exposure to synchrony, participants were exposed either to auditory-lagging asynchrony (VA group) or to auditory-leading asynchrony (AV group). The results revealed that RTs to sounds became progressively faster (in the VA group) or slower (in the AV group) as participants' exposure to asynchrony increased, thus providing empirical evidence that speeded responses to sounds are influenced by exposure to audiovisual asynchrony.

Audiovisual temporal adaptation of speech: temporal order versus simultaneity judgments.

The temporal perception of simple auditory and visual stimuli can be modulated by exposure to asynchronous audiovisual speech. For instance, research using the temporal order judgment (TOJ) task has shown that exposure to temporally misaligned audiovisual speech signals can induce temporal adaptation that will influence the TOJs of other (simpler) audiovisual events (Navarra et al. (2005) Cognit Brain Res 25:499-507). Given that TOJ and simultaneity judgment (SJ) tasks appear to reflect different underlying mechanisms, we investigated whether adaptation to asynchronous speech inputs would also influence SJ task performance. Participants judged whether a light flash and a noise burst, presented at varying stimulus onset asynchronies, were simultaneous or not, or else they discriminated which of the two sensory events appeared to have occurred first. While performing these tasks, participants monitored a continuous speech stream for target words that were either presented in synchrony, or with the audio channel lagging 300 ms behind the video channel. We found that the sensitivity of participant's TOJ and SJ responses was reduced when the background speech stream was desynchronized. A significant modulation of the point of subjective simultaneity (PSS) was also observed in the SJ task but, interestingly, not in the TOJ task, thus supporting previous claims that TOJ and SJ tasks may tap somewhat different aspects of temporal perception.