Object identification and attention training for treating tinnitus

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Abstract

We hypothesize that abnormal attention and auditory scene analysis contribute to the severity of tinnitus and that the incongruence between tinnitus and normal auditory perception is responsible for its resistance to traditional sound-based habituation therapies. New methods of treatment using auditory and visual attention training are proposed as a means to augment counseling and sound therapies for tinnitus management. Attention training has been demonstrated to improve an individuals’ ability to attend to relevant sounds while ignoring distracters. The main aim of the current study was to determine the effectiveness of structured Auditory Object Identification and Localization (AOIL) tasks to train persons to ignore their tinnitus. The study looked at the effects of a 15-day (30 min/day) take-home auditory training program on individuals with severe tinnitus. Pitch-matched tinnitus loudness levels (TLLs), tinnitus minimum masking levels (MMLs) and measures of attention were compared before and after the auditory training. The results of this study suggest that short-duration auditory training which actively engages attention, object identification and which requires a response from participants, reduces tinnitus. There was a greater effect on pitch-matched tinnitus MMLs than on actual TLLs. The reason(s) for this are unclear, although a correlation found between changes in MMLs and improvements in the ability to shift attention may be one underlying reason. Although this study followed a small number of participants over a limited time-span, it is believed that the training and accompanying model are a promising approach to investigate and treat some forms of tinnitus.

Introduction

The last two decades have seen major advances in understanding the neurophysiology of tinnitus (Eggermont and Roberts, 2004) (see Chapter 2) and its similarities to chronic pain (Møller, 2000). An area which has developed slower is our understanding of the cognitive aspects of tinnitus perception (Zenner and Zalaman, 2004). Simple perceptual constructs of tinnitus such as pitch and loudness may be insufficient as means of characterizing tinnitus. We need to extend our view of tinnitus as a phantom perception of a simple sound to incorporate concepts with greater ecological validity such as auditory object perception and figure ground differentiation (Winkler et al., 2006). The authors of this chapter consider that tinnitus is complex auditory activity that disobeys rules that normally apply to auditory object identification. We believe that abnormal attention (Hallam et al., 2004) and auditory scene analysis (ASA) (Bregman, 1990) contribute to the severity of tinnitus, and the incongruence between tinnitus and normal auditory perception is responsible for its resistance to traditional sound-based habituation therapies. The authors also acknowledge the importance of individual's reaction to tinnitus and non-auditory psychology (Henry and Wilson, 2001); but our research concentrates on how the perception of tinnitus and subsequent attention processes differ — or do not — from normal sound perception — and how a dichotomy of sound and tinnitus processing may account for over-attention to tinnitus. We believe that departures from normal auditory cognition lead to tinnitus’ resistance to habituation. The model we present in this chapter suggests that auditory training should lead to a diminution of tinnitus annoyance by improving processing of normal auditory activity compared to tinnitus activity.

Most bothersome chronic tinnitus appears to be the consequence of the central nervous system's (CNS) plasticity that may become expressed in response to altered activity from the inner ear (see Chapter 2). Normally, we are not aware of the background activity (spontaneous discharge) occurring in the auditory nerve (Eggermont and Sininger, 1995). However in a damaged inner ear, the rate and pattern of spontaneous discharge of the auditory nerve is altered (Martin et al., 1996; Searchfield et al., 2004). Increasing evidence from electrophysiology and imaging studies of the brain indicate that changes in output from the cochlea are enhanced by processing within the auditory pathways (Eggermont and Roberts, 2004). Changes in synaptic activity can lead to long-term anatomical and molecular change (Salvi et al., 2000). A persistent altered input to the central auditory system may result in functional changes in the auditory cortex similar to that believed to account for phantom limb pain in the somatosensory system (Muhlnickel et al., 1998; Møller, 2006). There is evidence that some forms of tinnitus involves other parts of the CNS than those normally activated by sound (Møller et al., 1992; Cacace, 2003). There is significant evidence that various cross-modal pathways are involved in tinnitus generation (Møller et al., 1992; Cacace, 2003). Some examples include: the modulation of tinnitus with oral-facial movements, with cranio-cervical manipulations, with finger and muscle movements (Levine, 1999) and skin stimulation and via trigeminal nerve interactions (Morgan, 1992). Normally the hearing system adapts to unimportant, continuous sounds. For a yet to be identified reason, the auditory system in many people with tinnitus does not habituate to the perception of tinnitus; instead it persists taking on an unusual importance (Cuny et al., 2004).

Perception is a mental representation of the world produced from the multitude of information impinging on our senses. In most environments a complex mixture of sounds reach the human ear. The auditory system needs to accurately separate out this input in order to make sense of the acoustic environment and ‘pick out’ relevant sounds. It is attention that allows us to select particular elements of sensory input for more detailed cognition (Spieth et al., 1954). A widespread, multimodal (auditory, visual, and tactile), cortical and sub-cortical network for the shifting of attention to relevant features of the sensory environment has been suggested on the basis of the results from neuroanatomical (Mesulam, 1981) and functional magnetic-resonance imaging studies (Downar et al., 2000). The ability to detect and then react to changes in the sensory environment is important for survival; thus, changes in the sensory environment are likely to draw attention involuntarily (Downar et al., 2000). For normal perception we must be able to select from the vast wealth of information entering the various sensory systems (Escera et al., 2000).

Attention is characterized by two aspects: selectivity and capacity limitation. Conscious perception is always selective. At any given moment we are aware of only a small fraction of the inputs stimulating our senses, as the brain continuously assigns priority to some sensory information over others (Pashler, 1998). While all conscious perception is selective to a certain degree, selective auditory attention refers specifically to the ability to select relevant information from surrounding sounds and ignore distracter stimuli (Giard et al., 2000) preferentially processing a particular set of sounds at expense of others (Alain and Arnott, 2000). This selectivity is essential for efficient management of information relay to the brain (Hughes and Jones, 2003). While the allocation of attention is usually voluntary and selective, sometimes attention is directed involuntarily, resulting in distraction (Jones, 1999). Directed selective attention is therefore in a state of tension with automatic processing of unattended information. It is important to maintain the integrity of selective attention in regards to relevant information, but it is also necessary for irrelevant information to compete for and possibly win control of attention. In that case, irrelevant information cannot be completely neglected. A balance between engaging selective attention and allowing flexibility must be maintained, in order to adapt to the changing environment. Competition from irrelevant sounds is an essential element of perception — but irrelevant sounds can corrupt the integrity of processing attended sounds (Hughes and Jones, 2003).

In principle, information gaining access to a limited-capacity attention system is controlled by two types of processes: active selection (focused attention) and the breakthrough of unattended stimuli (passive attention). For optimal functioning in a real-world environment, a balance between top-down (active) and bottom-up (passive) attention mechanisms must be maintained. If, for example, top-down mechanisms dominate attention, relevant (potentially dangerous) events outside the focus of attention may be ignored. On the other hand, if bottom-up mechanisms capture attention too easily, increased distractibility may result, making goal-directed behavior impossible. Such top-down/bottom-up imbalances can be seen in individuals with attention deficit hyperactivity disorder (ADHD), autistic spectrum disorder, dementia, schizophrenia, and brain injuries (Escera et al., 2000). Such an imbalance may also be found in conditions of milder injury or damage; for example, in tinnitus.

It is generally accepted that tinnitus does not obey many of the normal perceptual rules applying to sound (Henry and Meikle, 2000; Tyler, 2000). For example, tinnitus intensity matches are out of step with its perceived loudness — tinnitus may match to a quiet external sound but be perceived by the sufferer as being as loud as a jet engine. Although tinnitus may have a low-intensity match it can be difficult to mask (cover) it, even with very loud sounds close to the presumed tinnitus pitch (TP) (Feldmann, 1971; Mitchell, 1983; Burns, 1984). The reason, we believe, lies in ASA (Bregman, 1990). In everyday life we often listen to one sound, such as someone's voice in a background of competing sounds. To do this we must assign simultaneously occurring sound features (frequency, intensity, timbre) to the correct source and organize sounds appropriately over time. Recent research has focused on the underlying neural basis of a form of sequential organization known as auditory streaming (Carlyon, 2004). Auditory streams are the “objects” of audition and may underlie ASA. Like objects of visual perception, auditory objects generally correspond to physical objects in the environment. Importantly, these objects can be selectively attended to, processed and followed over time; suggesting that auditory streaming processes either receives input from non-auditory areas or feed into processes that do. We hypothesize that neural activity forming tinnitus is sufficiently different from normal sound activity that when formed into a whole it conflicts with memory of true sounds (e.g., tinnitus does not localize to an external source. An inability to localize a sound source is “unnatural” and a violation of a fundamental perceptual process). We also believe that it is the lack of a context, or a lack of behaviorally relevant meaning, that forces the brain to repeatedly or strongly attend to the tinnitus signal. In the case of a refrigerator motor making a humming sound in the background, which is easily habituated to, the distal source of the noise can be paired with a visual or tactile perception as well; the context of the noise is not in doubt, nor is its meaning; it can be processed and dismissed as unworthy of further attention. There is no such context or intrinsic meaning for the tinnitus signal, which is endogenous and does not correspond to an auditory object.

An auditory object is the percept of a group of sounds as a coherent whole. Ideally, this unit represents a single acoustic source (Griffiths and Warren, 2004). Identification of an auditory object involves information being generalized between particular sensory experiences in any one sensory domain (so that, e.g., we can recognize someone's voice over the telephone despite bandwidth distortions and understand a sentence regardless of accent or gender of the speaker; or we recognize the same face regardless of angle or lighting conditions). Auditory object identification is likely to involve at least two types of perceptual grouping — primitive grouping and schema-driven grouping (Bregman, 1990; Carlyon et al., 2001; Bey and McAdams, 2002; Alain and Izenberg, 2003; Sussman, 2005).

Primitive grouping is probably innate and pre-attentive and appears to follow the Gestalt principles of perceptual organization (Beauvois and Meddis, 1996; Moore and Egeth, 1997). The Gestalt psychologists of the early 1900s proposed a set of rules governing the formation of mental patterns from input sensory elements. These rules form the core of auditory grouping principles, which should also apply to tinnitus-related sensation.

As well as bottom-up primitive grouping, we also become aware of auditory objects by top-down processing. Schema-driven grouping relies on prior knowledge of familiar patterns in acoustic data. It involves past experience and context to organize sound into streams (Treisman and Gelade, 1980). Streams are then subjected to higher level processing. This in turn makes use of prior knowledge encoded in memory and “expectations” of what is likely and not likely (Cooke and Ellis, 2001). This model assumes that different qualities of the stimulus are not initially processed by the brain as a unit. Instead, different aspects, such as; what it is, where it is coming from, and who or what is producing it, are processed separately and simultaneously, before the stimulus is consciously perceived as a whole. This involves auditory stream segregation wherein sounds may be grouped to form meaningful representations of auditory objects in space. Features thought to play a key role in this auditory grouping include: spectral separation, spectral profile, harmonicity, onsets and offsets, coherent amplitude and frequency variations, spatial separation, temporal separation, bandwidth and phase (Moore and Gockel, 2002; Buchler et al., 2005). An auditory perception which exists in the absence of some features should lead to abnormal perception (e.g., tinnitus).

Once the aberrant neural activity that causes the sensation of tinnitus is processed and fails to be matched to existing templates, further attention resources may be allocated to identify signal features (Fig. 1). Due to our limited attention capacity, attention will normally be allocated to one auditory object (or a small group of them) at a time. This is known as the figure, while all other auditory information is relegated to ground and remains undifferentiated. The concept of figure-ground separation is clearly demonstrated visually by the profile/vase illusion (Rubin, 1915). The limitation must occur to some extent at a central stage, as interference is also found when one message is visual and one is auditory and this reflects our limited attention capacity (Treisman, 1964). Attention is required to produce figure-ground segregation. Processing capacity is allocated to the figure, and leaves the ground relatively undifferentiated. In complex or difficult auditory environments, attention mechanisms enhance the processing of relevant auditory inputs, and suppress those that are irrelevant (Eramudugolla et al., 2005). Unattended stimuli will be ignored depending on the level of perceptual expertise the subject already has in the stimulus (Ruz et al., 2005). The extremely emotional context of disabling tinnitus might lead to a higher level of selective attention directed toward the tinnitus signal; increasing distress and preventing adaptive responses.

The activation of attention and cognitive networks may contribute to the annoyance and the inability to habituate to tinnitus (Zenner and Zalaman, 2004). Impaired concentration and reduced ability to undertake cognitively demanding tasks are frequently reported by tinnitus patients. Evidence from several recent studies (Andersson, 2002; Hallam et al., 2004) supports these reports. Hallam et al. (2004) proposed that tasks requiring switching of attention would be difficult for tinnitus sufferers and demonstrated that, compared to a non-tinnitus group, tinnitus sufferers showed a clear difficulty in inhibiting activity in a dual task reaction time test. Jacobson et al. (1996) suggested that if selective attention is increased by the continuous presence of bothersome tinnitus, an automatic attention bias may begin to occur, resulting from listening to the continuous internally generated sound. Other studies seem to confirm this; Goodwin and Johnson, (1980) compared reaction times (RTs) to auditory stimuli in normal hearing (without tinnitus) and hearing-impaired (with tinnitus) individuals. RTs to auditory stimuli in the tinnitus group were significantly shorter at the tinnitus frequency suggesting some kind of cognitive enhancement of the tinnitus-linked neural signal processing. A study by Cuny et al. (2004) has provided evidence for an automatic direction of attention toward the tinnitus ear (in cases of unilateral tinnitus). Involuntary attention shifts may be affected by the processing of the tinnitus signal, as individuals with tinnitus seem to have more difficulty redirecting their attention to something, which is not their tinnitus — including a sound that simulates the person's tinnitus. The presence of real tinnitus might direct attention automatically to the tinnitus ear and this direction of attention affects an automatically operating “deviance detection system” (Schroger, 1997). This “attention capture” effect was also proposed to reflect an ability of the CNS to detect inconsistency within a set of stimuli and to direct information processing automatically toward the deviant stimulus. Cuny et al. (2004) feel that this supports the hypothesis that the attention system does not allow the tinnitus signal to be classified as irrelevant information. Such a mechanism is similar to models proposed to explain how auditory hallucinations may arise from changed peripheral activity (Grossberg, 2000).

It has become increasingly clear that all areas of the brains of primates (including humans) maintain a high degree of plasticity, even into adulthood and brain function can alter with training (Buonomano and Mersenich, 1998; Syka, 2002). Therapies using sound and training attempt to use this plasticity to their advantage by modifying brain function. Attention training is based on the premise that attention abilities can be improved by activating particular aspects of attention through a stimulus-drill approach. It is thought that repeatedly stimulating attention systems via graded attention exercises will promote changes in attention functioning (Sohlberg and Mateer, 1987) and lead to plastic changes in the brain. Such structured attention training oriented programs have been designed for treatment of patients with attention deficits such as can accompany acquired brain injuries (Sohlberg and Mateer, 1987) and schizophrenia (Lopez-Luengo and Vazquez, 2003). Although it is well accepted that tinnitus and auditory hallucinations are very different experiences, poor concentration, and inability to ignore the phantom sounds accompany both (Johns et al., 2002; Behrendt and Young, 2004). Therefore, an effective treatment might address problems common to both tinnitus and schizophrenia. The Attention Process Training (APT) program developed by Sohlberg and Mateer (1987) is a cognitive rehabilitation program originally designed to remediate attention deficits in individuals with brain injury. The APT materials consist of a group of tasks that exercise different components of attention commonly impaired after brain injury including: sustained, selective, alternating, and divided attention. The program tasks place increasing demands on complex attention control and working memory systems. Exercises include listening for descending number sequences, alphabetizing words in an orally presented sentence, and detecting targets with the presence of distracter noise. The use of APT in patients with specific brain injury has led to improvements in executive attention that have been reported to generalize to tasks remote from the training tasks (Rueda et al., 2005). APT has also proven to be successful in training attention abilities in children with ADHD (Kerns et al., 1999). Attention training appears to be most effective when directed at improving the subject's performance on complex, functional tasks (Robinson and Summerfield, 1996).

Hatashita-Wong and Silverstein (2003) described a program for treatment of attention deficit disorders — based on principles similar to APT (increasing attention load) — for a patient who had attention deficits co-existing with auditory hallucinations. This therapy is intended to enable disattention (increased ignoring) of abnormal perceptions. A dichotic listening paradigm was recorded on audiotape; during playback the patient practiced attending to a target stimulus while ignoring irrelevant information at different spatial locations. Difficulty of task was increased as performance improved. After training the client was able to resist distraction to internal stimuli and had an increased ability to stay on-task (Hatashita-Wong and Silverstein, 2003).

Traditionally, in tinnitus therapy, sound has been used in a passive, non-attended manner to mask or facilitate habituation to tinnitus (Henry et al., 2002). Active auditory discrimination training listening tasks have recently been trialed as a component of therapies for tinnitus with some success (Flor et al., 2004). Flor et al (2004) found an effect regardless of the frequency of the tinnitus or the frequencies of sounds discriminated. Instead, treatment success was best predicted by the amount of regular training undertaken by individuals and psychological variables. These results suggest that the reduction in tinnitus associated with pitch discrimination tasks may be the consequence of attention mechanisms rather than frequency-specific reorganization (Brown et al., 2004).

In the present study, described below, persons with tinnitus were provided with training tasks, which involved actively focusing auditory attention on specific auditory objects and locations, while ignoring simultaneous background noise. In a review of auditory learning and training in adults, Robinson and Summerfield (1996) argue that three principles of learning are relevant for auditory training: (1) the more complex the task the longer the training period; (2) the greater the similarity between training and test tasks the greater the transfer, and (3) The more the training represents the variability of the auditory object of interest (e.g., speech or tinnitus) the greater the transfer to everyday life (Robinson and Summerfield, 1996). As our goal was to train tinnitus patients to hear environmental sounds instead of their tinnitus, the training task required auditory object identification and location; rather than simple sound discrimination. It was hypothesized that after participants had undergone a short period of auditory attention training, they would be able to direct their auditory attention to exogenous/environmental auditory objects more easily, and more automatically, than prior to training. It was also hypothesized that the training would reduce their tinnitus awareness by enabling focus of attention on sounds other than tinnitus.

The specific aims of this study were to determine if auditory attention training could induce subjective changes in tinnitus minimum masking levels (MMLs) and pitch-matched tinnitus loudness levels (TLLs), and attempt to correlate any changes with changes in measures of attention.

Section snippets

Methods

This study was approved by the University of Auckland Human Participants Ethics Committee on 15th of June 2006 (reference 2006/137). Subject data was recorded using Microsoft Excel 2003, and the statistical analysis was performed using SAS System 9.1.

Auditory/Visual Discriminate Reaction Time Test

Auditory and Visual tasks of the CAB had 70 stimuli with 35 targets and the shift task had 90 stimuli with 30 targets (stimulus duration: visual=200 ms and auditory=300 ms; inter-stimulus interval=1800 ms). For the Visual Discriminate Reaction Time Test each participant was presented with a gray square in the center of the screen as described previously. Each participant was instructed to touch the center gray square as quickly as they could whenever they saw it flash red and not when it flashed

Results

The characteristics of the participants prior to training are summarized in Table 1. Individual tinnitus pitch-match ranged from 0.5 to 12 kHz and tinnitus loudness was 10 dB SL (SD=5). MMLs centered closest to TP varied from just above 12 to 46 dB SL, MMLs were generally low- to high-frequency NBN (not shown).

Seven of the 10 participants had a reduction in their pitch-matched TLL following training (Fig. 3 and Table 2). Two of the participants (B.B. and D.J.) displayed no change in loudness

Discussion

The way people perceive their tinnitus is a significant contributor to tinnitus severity and to the difficulties to habituate to it (Zenner and Zalaman, 2004). We have presented a model of tinnitus cognition, which incorporates tinnitus within concepts of scene analysis and attention. We believe that the difference between ASA of normal sound and tinnitus inhibits habituation. This study showed that training to improve attention to auditory objects, other than tinnitus can reduce tinnitus

Conclusion

The present study investigated the effects of a short, take-home auditory training program on psychoacoustic measures of tinnitus. MMLs and TLL were reduced in most participants following training — consistent with the hypothesis that a demanding auditory identification and localization-training task should improve identification of non-tinnitus auditory objects. The study supported the hypothesis that active training, which engages attention, may be effective in a shorter time than some

Abbreviations

    ADHD

    Attention Deficit Hyperactivity Disorder

    ANOVA

    Analysis of Variance

    AOIL

    Auditory Object Identification and Localization

    APT

    Attention Process Training

    ASA

    Auditory Scene Analysis

    CAB

    Comprehensive Attention Battery

    CNS

    Central Nervous System

    DRTa

    Auditory Discriminate Reaction Time Test

    DRTs

    Shift Discriminate Reaction Time Test

    MML

    Minimum Masking Level

    NBN

    Narrow Band Noise

    PDA

    Personal Digital Assistant

    RT

    Reaction Time

    SICT

    Stroop Interference Cancellation Test

    TLL

    Tinnitus Loudness Level

    TP

    Tinnitus Pitch

    VR

    Virtual

Acknowledgments

The authors are grateful to the Tinnitus Research Initiative (TRI) for funding our research. We thank Michael Sanders for his contribution in the development of the AOIL.

References (75)

  • G.D. Searchfield et al.

    Ensemble spontaneous activity in the guinea-pig cochlear nerve

    Hear. Res.

    (2004)
  • A.M. Treisman et al.

    A feature-integration theory of attention

    Cogn. Psychol.

    (1980)
  • C. Alain et al.

    Selectively attending to auditory objects

    Front. Biosci.

    (2000)
  • C. Alain et al.

    Effects of attentional load on scene analysis

    J. Cogn. Neurosci.

    (2003)
  • G. Andersson

    A cognitive-affective theory for tinnitus: experiments and theoretical implications

  • M. Atienza et al.

    Posttraining sleep enhances automaticity in perceptual discrimination

    J. Cogn. Neurosci.

    (2004)
  • M.W. Beauvois et al.

    Computer simulation of auditory stream segregation in alternating-tone sequences

    J. Acoust. Soc. Am.

    (1996)
  • R.-P. Behrendt et al.

    Hallucinations in schizophrenia, sensory impairment, and brain disease: a unifying model

    Behav. Brain Sci.

    (2004)
  • C. Bey et al.

    Schema-based processing in auditory scene analysis

    Percept. Psychophys.

    (2002)
  • A.S. Bregman

    Auditory scene analysis. The perceptual organization of sound

    (1990)
  • M. Brown et al.

    Perceptual learning on an auditory frequency discrimination task by cats: association with changes in primary auditory cortex

    Cereb. Cortex

    (2004)
  • M. Buchler et al.

    Sound classification in hearing aids inspired by auditory scene analysis

    EURASIP J. Appl. Signal Process.

    (2005)
  • D.V. Buonomano et al.

    Cortical plasticity: from synapses to maps

    Annu. Rev. Neurosci.

    (1998)
  • E.M. Burns

    A comparison of variability among measurements of subjective tinnitus and objective stimuli

    Audiology

    (1984)
  • R.P. Carlyon et al.

    Effects of attention and unilateral neglect on auditory stream segregation

    J. Exp. Psychol. Hum. Percept. Perform.

    (2001)
  • C. Cuny et al.

    Reduced attention shift in response to auditory changes in subjects with tinnitus

    Audiol. Neurootol.

    (2004)
  • J. Downar et al.

    A multimodal cortical network for the detection of changes in the sensory environment

    Nat. Neurosci.

    (2000)
  • J.J. Eggermont et al.

    Correlated neural activity and tinnitus

  • C. Escera et al.

    Involuntary attention and distractibility as evaluated with event-related brain potentials

    Audiol. Neurootol.

    (2000)
  • H. Feldmann

    Homolateral and contralateral masking of tinnitus by noise-bands and by pure tones

    Audiology

    (1971)
  • H. Flor et al.

    Auditory discrimination training for the treatment of tinnitus

    Appl. Psychophysiol. Biofeedback

    (2004)
  • M.H. Giard et al.

    Neurophysiological mechanisms of auditory selective attention in humans

    Front. Biosci.

    (2000)
  • P.E. Goodwin et al.

    A comparison of reaction times to tinnitus and nontinnitus frequencies

    Ear Hear.

    (1980)
  • C. Green et al.

    Action video game modifies visual selective attention

    Nature

    (2003)
  • T.D. Griffiths et al.

    What is an auditory object?

    Nat. Rev. Neurosci.

    (2004)
  • S. Grossberg

    How hallucinations may arise from brain mechanisms of learning, attention, and volition

    J. Int. Neuropsychol. Soc.

    (2000)
  • R.S. Hallam et al.

    Tinnitus impairs cognitive efficiency

    Int. J. Audiol.

    (2004)
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