Rationale and protocol of the ENGAGE study: a double-blind randomized controlled preference trial using a comprehensive cohort design to measure the effect of a cognitive and leisure-based intervention in older adults with a memory complaint.

BACKGROUND: Leisure activities can be both enjoyable and cognitively stimulating, and participation in such activities has been associated with reduced age-related cognitive decline. Thus, integrating stimulating leisure activities in cognitive training programs may represent a powerful and innovative approach to promote cognition in older adults at risk of dementia. The ENGAGE study is a randomized controlled, double-blind preference trial with a comprehensive cohort design that will test the efficacy and long-term impact of an intervention that combines cognitive training and cognitively stimulating leisure activities. METHODS: One hundred and forty-four older adults with a memory complaint will be recruited in Montreal and Toronto. A particular effort will be made to reach persons with low cognitive reserve. Participants will be randomly assigned to one of two conditions: cognitive + leisure training (ENGAGE-MUSIC/SPANISH) or active control (ENGAGE-DISCOVERY). The ENGAGE-MUSIC/SPANISH training will include teaching of mnemonic and attentional control strategies, casual videogames selected to train attention, and classes in music or Spanish as a second language. The ENGAGE-DISCOVERY condition will comprise psychoeducation on cognition and the brain, low-stimulating casual videogames and documentary viewing with discussions. To retain the leisure aspect of the activities, participants will be allowed to exclude either music or Spanish at study entry if they strongly dislike one of these activities. Participants randomized to ENGAGE-MUSIC/SPANISH who did not exclude any activity will be assigned to music or Spanish based on a second random assignment. Training will be provided in 24 2-h sessions over 4 months. Outcomes will be measured at baseline, at 4-month follow-up, and at 24-month follow-up. The primary outcome will be cognitive performance on a composite measure of episodic memory (delayed recall scores for words and face-name associations) measured at baseline and at the 4-month follow-up. Secondary outcomes will include a composite measure of attention (speed of processing, inhibition, dual tasking, and shifting), psychological health, activities of daily living, and brain structure and function and long-term maintenance measured at the 24-month follow-up. Information on cognitive reserve proxies (education and lifestyle questionnaires), sex and genotype (apolipoprotein (Apo)E4, brain-derived neurotrophic factor (BDNF), and catechol-O-methyltransferase (COMT)) will be collected and considered as moderators of training efficacy. DISCUSSION: This study will test whether a program combining cognitive training with stimulating leisure activities can increase cognition and reduce cognitive decline in persons at risk of dementia. TRIAL REGISTRATION: NCT03271190 . Registered on 5 September 2017.

Effects of relative phases on pitch and timbre in the piano bass range.

Piano bass tones raise questions related to the perception of multicomponent, inharmonic tones. In this study, the influence of the relative phases among partials on pitch and timbre was investigated for synthesized bass tones with piano-like inharmonicity. Three sets of bass tones (A0 = 27.5 Hz, 100 partials, flat spectral envelope) were generated; harmonic, low inharmonic, and high inharmonic. For each set, five starting phase relations among partials were applied; sine phases, alternate (sine/cosine) phases, random phases, Schroeder phases, and negative Schroeder phases. The pitch and timbre of the tones were influenced markedly by the starting phases. Listening tests showed that listeners are able to discriminate between tones having different starting phase relations, and also that the pitch could be changed by manipulating the relative phases (octave, fifth, major third). A piano-like inharmonicity gives a characteristic randomizing effect of the phase relations over time in tones starting with nonrandom phase relations. A measure of the regularity of the phase differences between adjacent partials is suggested for quantifying this randomization process. The observed phase effects might be of importance in synthesizing, recording, and reproducing piano music.

Impaired short temporal interval discrimination in a dyslexic adult.

The ability to discriminate short temporal intervals was examined in a dyslexic adult (E.C.) and six matched controls. Listeners had to decide whether the second interval was shorter or longer than a standard (target) interval. Each interval was defined as the silent duration between two successive brief tones. Eight target intervals were used, ranging from 100 to 1,200 ms in duration. At each target interval, the differential threshold (DL) for duration was assessed, with the use of an adaptive psychophysical procedure. The results show that E.C.'s differential threshold values were much larger than those of controls. Moreover, the slope estimates covering the duration range from 100 to 800 ms indicated that in comparison to controls, E.C.'s differential threshold increased dramatically as the target duration increased. Thus her timing impairment becomes more pronounced with increasing duration. This timing deficit is consistent with other studies that have found temporal processing deficits associated with dyslexia.

Dissociations among functional subsystems governing melody recognition after right-hemisphere damage.

This study describes an amateur musician, KB, who became amusic following a right-hemisphere stroke. A series of assessments conducted post-stroke revealed that KB functioned in the normal range for most verbal skills. However, compared with controls matched in age and music training, KB showed severe loss of pitch and rhythmic processing abilities. His ability to recognise and identify familiar instrumental melodies was also lost. Despite these deficits, KB performed remarkably well when asked to recognise and identify familiar song melodies presented without accompanying lyrics. This dissociation between the ability to recognise/identify song vs. instrumental melodies was replicated across different sets of musical materials, including newly learned melodies. Analyses of the acoustical and musical features of song and instrumental melodies discounted an explanation of the dissociation based on these features alone. Rather, the results suggest a functional dissociation resulting from a focal brain lesion. We propose that, in the case of song melodies, there remains sufficient activation in KB's melody analysis system to coactivate an intact representation of both associative information and the lyrics in the speech lexicon, making recognition and identification possible. In the case of instrumental melodies, no such associative processes exist; thus recognition and identification do not occur.

Music training and rate of presentation as mediators of text and song recall.

The present research addresses whether music training acts as a mediator of the recall of spoken and sung lyrics and whether presentation rate is the essential variable, rather than the inclusion of melody. In Experiment 1, 78 undergraduates, half with music training and half without, heard spoken or sung lyrics. Recall for sung lyrics was superior to that for spoken lyrics for both groups. In Experiments 2 and 3, presentation rate was manipulated so that the durations of the spoken and the sung materials were equal. With presentation rate equated, there was no advantage for sung over spoken lyrics. In all the experiments, those participants with music training outperformed those without training in all the conditions. The results suggest that music training leads to enhanced memory for verbal material. Previous findings of melody's aiding text recall may be attributed to presentation rate.

Expectancies generated by melodic intervals: evaluation of principles of melodic implication in a melody-completion task.

Bottom-up principles of melodic implication (Narmour, 1990) were evaluated in a melody-completion task. One hundred subjects (50 low training; 50 high training in music) were presented each of eight melodic intervals. For each interval, the subjects were asked to compose a short melody on a piano keyboard, treating the interval provided as the first two notes of the melody. For each melody, the first response--the note immediately following the initial interval--was analyzed. Multinomial log linear analyses were conducted to assess the extent to which responses could be predicted by Narmour's (1990, 1992) bottom-up principles. Support was found for all of Narmour's principles, and two additional predictors based on implied tonal structure. Responses of low- and high-training groups were similar.

Music performance and the perception of key.

The effect of music performance on perceived key movement was examined. Listeners judged key movement in sequences presented without performance expression (mechanical) in Experiment 1 and with performance expression in Experiment 2. Modulation distance varied. Judgments corresponded to predictions based on the cycle of fifths and toroidal models of key relatedness, with the highest correspondence for performed versions with the toroidal model. In Experiment 3, listeners compared mechanical sequences with either performed sequences or modifications of performed sequences. Modifications preserved expressive differences between chords, but not between voices. Predictions from Experiments 1 and 2 held only for performed sequences, suggesting that differences between voices are informative of key movement. Experiment 4 confirmed that modifications did not disrupt musicality. Analyses of performances further suggested a link between performance expression and key.

Dissociation of musical tonality and pitch memory from nonmusical cognitive abilities.

The main purposes of this study were to replicate, validate, and extend measures of sensitivity to musical pitch and to determine whether performance on tests of tonal structure and pitch memory was related to, or dissociated from, performance on tests of nonmusical cognitive skills--standardized tests of cognitive abstraction, vocabulary, and memory for digits and nonrepresentational figures. Factor analyses of data from 100 neurologically intact participants revealed a dissociation between music and nonmusic variables, both for the full data set and a set for which the possible contribution of levels of music training was statistically removed. A neurologically impaired participant, C.N., scored within the range of matched controls on nonmusic tests but much lower than controls on music tests. The study provides further evidence of a functional specificity for musical pitch abilities.

Expectancies generated by melodic intervals: perceptual judgments of melodic continuity.

The present study tested quantified predictors based on the bottom-up principles of Narmour's (1990) implication-realization model of melodic expectancy against continuity ratings collected for a tone that followed a two-tone melodic beginning. Twenty-four subjects (12 musically trained, 12 untrained) were presented with each of eight melodic intervals--two successive tones which they were asked to consider as the beginning of a melody. On each trial, a melodic interval was followed by a third tone, one of the 25 chromatic notes within the range one octave below to one octave above the second tone of the interval. The subjects were asked to rate how well the third tone continued the melody. A series of regression analyses was performed on the continuation ratings, and a final model to account for the variance in the ratings is proposed. Support was found for three of Narmour's principles and a modified version of a fourth. Support was also found for predictor variables based on the pitch organization of tonal harmonic music. No significant differences between the levels of musical training were encountered.

Responsiveness of Western adults to pitch-distributional information in melodic sequences.

Responsiveness of musically trained and untrained adults to pitch-distributional information in melodic contexts was assessed. In Experiment 1, melodic contexts were pure-tone sequences, generated from either a diatonic or one of four nondiatonic tonesets, in which pitch-distributional information was manipulated by variation of the relative frequency of occurrence of tones from the toneset. Both the assignment of relative frequency of occurrence to tones and the construction of the (fixed) temporal order of tones within the sequences contravened the conventions of western tonal music. A probe-tone technique was employed. Each presentation of a sequence was followed by a probe tone, one of the 12 chromatic notes within the octave. Listeners rated the goodness of musical fit of the probe tone to the sequence. Probe-tone ratings were significantly related to frequency of occurrence of the probe tone in the sequence for both trained and untrained listeners. In addition, probe-tone ratings decreased as the pitch distance between the probe tone and the final tone of the sequence increased. For musically trained listeners, probe-tone ratings for diatonic sequences tended also to reflect the influence of an internalized tonal schema. Experiment 2 demonstrated that the temporal location of tones in the sequences could not alone account for the effect of frequency of occurrence in Experiment 1. Experiment 3 tested musically untrained listeners under the conditions of Experiment 1, with the exception that the temporal order of tones in each sequence was randomized across trials. The effect of frequency of occurrence found in Experiment 1 was replicated and strengthened.

Asymmetry of perceived key movement in chorale sequences: converging evidence from a probe-tone analysis.

In a probe-tone experiment, two groups of listeners--one trained, the other untrained, in traditional music theory--rated the goodness of fit of each of the 12 notes of the chromatic scale to four-voice harmonic sequences. Sequences were 12 simplified excerpts from Bach chorales, 4 nonmodulating, and 8 modulating. Modulations occurred either one or two steps in either the clockwise or the counterclockwise direction on the cycle of fifths. A consistent pattern of probe-tone ratings was obtained for each sequence, with no significant differences between listener groups. Two methods of analysis (Fourier analysis and regression analysis) revealed a directional asymmetry in the perceived key movement conveyed by modulating sequences. For a given modulation distance, modulations in the counterclockwise direction effected a clearer shift in tonal organization toward the final key than did clockwise modulations. The nature of the directional asymmetry was consistent with results reported for identification and rating of key change in the sequences (Thompson & Cuddy, 1989a). Further, according to the multiple-regression analysis, probe-tone ratings did not merely reflect the distribution of tones in the sequence. Rather, ratings were sensitive to the temporal structure of the tonal organization in the sequence.

Effects of metric and harmonic rhythm on the detection of pitch alterations in melodic sequences.

Tested response time to alterations. Metric rhythm and harmonic rhythm of 13-note tonal sequences were either matched or mismatched. Metric rhythm (3/4 or 4/4 meter) was induced by dynamic accents. Harmonic rhythm was induced by implied chord progressions initiated on the first note and on either every third or every fourth note. Responses were not always faster for matched rhythms or for alterations occurring on the dynamic accent. Responses were consistently faster for sequences presented in 4/4 meter. Musically untrained Ss performed similarly to trained Ss, but were slower and more variable. Accuracy of recall on a music dictation task also favored 4/4 meter rather than matched rhythms. Coding of pitch content may have been facilitated by the structural framework of 4/4 meter rather than by expectancies arising from the match of temporal and pitch organization.

Octave discrimination: an experimental confirmation of the "stretched" subjective octave.

Discrimination of the musical octave was measured by the method of constant stimuli with roving standards and four response categories. For each of three musically trained listeners, and two of three untrained listeners, the estimated value of the subjective octave was "stretched" slightly sharper than the physical octave of 1200 cents. The magnitude of this stretch, about 20 cents on the average, replicated earlier findings obtained by the method of adjustment. A Thurstonian decision-theory model, providing iterative parametric solutions, generated an excellent fit to listeners' psychophysical functions. The present experimental task is best described by a noncategorical model of interval perception.

Perception of structure in short melodic sequences.

Three experiments studied the perception of tone sequences having various degrees of musical structure. Ratings of perceived structure and ease of recognition in transposition were both influenced by harmonic progression (as defined by music theory), the contour (directional changes in pitch), and the excursion or repetition pattern within the sequence. The relation between the original and transposed sequence also affected ease of recognition in accordance with the number of tones shared between the two sequences. The results are described in terms of the abstraction and analysis of levels of pitch relations, an analysis conducted even by musically untrained listeners. The conceptual framework emphasizes the application of musical rules as an illustration of rules governing auditory sequences in general.

Recognition memory for single tones with and without context.

Sequences of seven tones were presented, and recognition memory for individual tones of each sequence was tested under varying degrees of context. With no context, the test required recognition of a tone isolated from the sequence; with full context, the tone to be recognized was embedded in the original sequence. A series of three experiments demonstrated that recognition memory was far more accurate under full-context conditions than under no-context conditions and that the superiority was not wholly attributable to the serial position information or the order information provided by the full context. It is suggested that in addition to the processing of limited information for the pitch of isolated tones, pattern (or relational) information is abstracted from a tone sequence and is retrieved in the presence of full context.