3/25/2010. Multitasking

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1 Walking & Chewing Gum Divided Attention In Hearing and Balance Scott K. Griffiths, Ph.D. March 25, 2010 Multitasking Us Topics for Today Attention and Executive Function Listening Balance & Gait What Should We Be Doing? 1

2 Executive Function A variety of higher cognitive processes that use and modify information from many cortical sensory systems to modulate and produce behavior. Yogev-Seligmann (2008) Executive Functions Volition Self-Awareness Planning Response Inhibition Response Monitoring Attention / Dual Tasking INTENTION Executive Function Anatomically supported through a widely distributed network of sites, including: frontal lobe, cingulate gyrus, parietal lobe, So areas known to be involved in the initiation of thought, sensory integration, emotion, and memory 2

3 Aging and EF Performance on EF tasks Processing speed Memory = IQ Anatomically: white matter hyperintensities in frontal lobe; loss of dendritic branching; gray matter tissue loss; decrease in dopaminergic activity CAVEAT: Pay attention to ADLs Attention A set of different processes that are related aspects of how an organism becomes receptive to stimuli and how it may begin processing incoming or attended-to to excitation, whether internal or external. Lezak, 1995 Features of Attention Focused or Selective Attention Sustained Attention Divided Attention Alternating Attention 3

4 Dual Tasking Doing two things at once How well you do them may provide a measure of divided attention A common protocol for looking at this Can quantify attentional demands of a task Theories: Capacity Sharing Bottleneck Multiple Resource Models Divided Attention Impacts Auditory Processing Performance Plays a strong role in Gait When multitasking In changing situations Has clinical implications for Fall Risk Attention and Listening The challenge of listening in the real world Auditory Objects and Streaming Divided Attention Dual Task Performance 4

5 Our Listening Environment Original source Other voices Environmental sounds Reflected sounds Producing Masking: Energetic & Informational Auditory Scene Analysis Bregman (1990) Listeners build auditory objects representations of sound sources Based on Gestalt cues Similarity Proximity Quality of Continuity The perceptual unit of attention is the object. Shinn-Cunningham,

6 Auditory Object Formation Energetic Masking Attending to Objects We attend to only one object at a time But actively switch attention ( ms) Missing bits filled in With short term sensory memory Signal redundancy Linguistic (lexical/semantic) constraints Shinn-Cunningham (2008) 6

7 Streaming Attending to a string or stream of auditory objects (e.g., syllables) Based on a distinguishing feature For speech: Spectro-temporaltemporal patterns That the listener has a priori knowledge of: Parallel Search: Competition has less effect If not, listener must sample from competing streams. Serial Search: performancedrops Divided Attention Spatial Separation Improves Ability to: Hear otherwise masked portions of signal. Segregate talkers into separate streams. Selectively focus on a less-intense talker. Voice,Location & Streaming Kidd, et al. (2008) 7

8 Correct Syntax Aids Recognition Target and Masker words interleaved Correlated words form syntactically correct sentences Random words do not Kidd, et al. (2008) Challenges to Object Formation Similarity of sources Inconsistency of features When sources are distinct and consistent: SUCCESS! Shinn-Cunningham (2008) In Complex Situations Auditory Objects can be unstable But But, Object formation can build up over time, and Selective Attention can improve. 8

9 Salience & The Impact of Peripheral Hearing Loss Shinn-Cunningham & Best (2008) Peripheral Hearing Loss & Sensory Memory Trace Challenges, cont d Directing attention to wrong object Can t select features to attend to Features too similar between target and other objects Competing object more salient 9

10 Failure of Auditory Streaming Why would I have my hearing aid turned off? Dad, is your hearing aid turned on? Dear, can we turn the TV off? Alcohol and Attentional Control Rossello, Munar, Justo & Arlas (1999) What are the auditory analogs of this visual illustration? And what does it mean for your patients? How can assistive devices help? 10

11 So Who Has Problems with Auditory Attention? Those with Peripheral Hearing Loss Broader auditory filters Poorer tracking of spectrotemporal changes Those with cognitive deficits Dementia Intoxication Those with less experience Children Working in a second language Executive Function in APD Testing? EF should be a fundamental component of success in the tasks on any test from the APD battery We began with dichotic digits Can Instructions Impact Performance? A non-auditory, low verbal load 2 nd task Limits of Stability Protocol A Continuous Visual Vigilance Task Provides Accuracy Reaction Time 11

12 Triple Pairs Mean Performance (+/- 1 s.d.) % Correct Right Left Right Left Right Left 1st 2nd Aud Alone Undirected Pairs REF/LEF Condition Mean Dichotic Digits Triple Pairs Performance for Adults (+/- 2 SEM) rrect % Co Right Left Right Left Right Left Aud Alone Undirected Pairs Condition Mean Dichotic Digits Triple Pairs Performance for Adolescents (+/- 2 SEM) rrect % Cor Right Left Right Left Right Left Aud Alone Undirected Pairs Recall Condition 12

13 Some Individual Differences In Adults Individual Differences: Dichotic Digit Triple Pairs % Correct Right Left Right Left Right Left Aud Alone Undirected Pairs Condition APD Dyslexia Gait, Balance & Fall Prevention Falls Common Among Elders 30% will have 1 per year 50% incidence among females over 85 60% of fallers will fall again Not always producing injury, but Common Outcomes of Falls Reduced Activity Levels Deconditioning/Weakness Enhanced Risk for Future Falls Reduced Quality of Life 13

14 In Y2K, Falls are Expensive US $ 20 billion UK 981 million Account for up to 5% of all hospital charges Fall complications are the 5 th leading cause of death in the elderly Physiologic Issues In Falls Loss of Balance Weakness Abnormal Movements Abnormal Cognition/Mood Alvord (2008) Cognitive Role in Gait & Balance? Hausdorff (2005) Gait correlates better with more complex task. Correlation between EF and Gait is strong even when accounting for Leg strength Age Activity Level But no causative role proven yet 14

15 Executive Function Predicts Features of Gait Aging & Dual-Task Gait Studies Why? Decline in Executive Function Lundin-Olsson (1997) Walk-Talk predicts falls Healthy folks (all ages) show gait slowing Older adults: some poorer gait stability When walking more complex course Poorer gait speed & stability in Elderly with Polypharmacy Dementia Movement Abnormalities Prioritization Williams (2005): normal weighting to Minimize Danger/Maximize Pleasure Unconscious posture first strategy A posture second strategy seen in Fallers and PD patients 15

16 Prioritization & Fall Risk Fallers prioritize planning of future steps At the expense of Execution of ongoing movements Beauchet (2007) Prospective study Dual task: Arithmetic while Walking Fallers (in the following months) did better on the math than Non-Fallers. Dual Tasking & Falls Dual Tasking in Parkinson Disease 16

17 So What Are We To Do? Encourage your elderly patients to keep active. Training Works! for both fallers and non-fallers (Toulotte,2006) Fall Prevention measures Keep in mind Pharmacologic options Dual Task in Auditory Processing Evaluations What Else? Help your patients understand that hearing is more than detecting tones If you give them some understanding of the way the brain works with sound, they CAN change their own brains. Keep your eye on the literature. Thanks to: Lynnette Bardolf, Ph.D. Jay Sheehan, Ph.D. Sana Al-Bustan Lilian Yac Cyndi Trueheart & CSHA 17