Speechreading and Aging

The purpose of the present study was to examine the effects of age on the ability to benefit from combining auditory and visual speech information, relative to listening or speechreading alone. In addition, the study was designed to compare visual enhancement (VE) and auditory enhancement (AE) for consonants, words, and sentences in older and younger adults. Forty-four older adults and 38 younger adults with clinically normal thresholds for frequencies of 4 kHz and below were asked to identify vowel-consonant-vowels (VCVs), words in a carrier phrase, and semantically meaningful sentences in auditory-only (A), visual-only (V), and auditory-visual (AV) conditions. All stimuli were presented in a background of 20-talker babble, and signal-to-babble ratios were set individually for each participant and each stimulus type to produce approximately 50% correct in the A condition. For all three types of stimuli, older and younger adults obtained similar scores for the A condition, indicating that the procedure for individually adjusting signal-to-babble ratios was successful at equating A scores for the two age groups. Older adults, however, had significantly poorer performance than younger adults in the AV and V modalities. Analyses of both AE and VE indicated no age differences in the ability to benefit from combining auditory and visual speech signals after controlling for age differences in the V condition. Correlations between scores for the three types of stimuli (consonants, words, and sentences) indicated moderate correlations in the V condition but small correlations for AV, AE, and VE. Overall, the findings suggest that the poorer performance of older adults in the AV condition was a result of reduced speechreading abilities rather than a consequence of impaired integration capacities. The pattern of correlations across the three stimulus types indicates some overlap in the mechanisms mediating AV perception of words and sentences and that these mechanisms are largely independent from those used for AV perception of consonants.

This study examined age-related changes in the ability to integrate auditory and visual speech information. Visual enhancement, the advantage afforded by seeing as well as hearing a talker, compared with listening alone, was measured in younger (18–25) and older (over age 65) adults. In addition, dichotic identification of filtered speech (auditory–auditory speech integration) and binaural gap detection (auditory–auditory nonspeech integration) were tested to evaluate whether auditory-visual integration was related to a more global ability to integrate sensory signals, be they speech or nonspeech. Visual enhancement was significantly impaired in older, compared with younger adults. Importantly, visual-only (lipreading) performance of younger and older adults was nearly identical, suggesting that age-related declines in visual enhancement were not a result of reduced reception of visual information. Older adults also exhibited deficits in the ability to integrate two channels of auditory information and these deficits were similar for both speech (sentences) and nonspeech (gap detection) stimuli. Regression analyses indicated significant correlations between the three measures of sensory integration, visual enhancement, dichotic sentence identification, and binaural gap detection. Taken together, the findings suggest that age-related declines in visual enhancement are a result of a generalized decline in sensory integration abilities.

Speech understanding is improved when the observer can both see and hear the talker. This study compared the effects of reduced visual acuity on auditory-visual (AV) speech-recognition in noise among younger and older adults. Two groups of participants performed a closed-set sentence-recognition task in one auditory-alone (A-alone) condition and under three AV conditions: normal visual acuity (6/6), and with blurred vision to simulate a 6/30 and 6/60 visual impairment. The results showed that (1) the addition of visual speech cues improved speech-perception relative to the A-alone condition, (2) under the AV conditions, performance declined as the amount of blurring increased, (3) even under the AV condition that simulated a visual acuity of 6/60, the speech recognition scores were significantly higher than those obtained under the A-alone condition, and (4) generally, younger adults obtained higher scores than older adults under all conditions. Our results demonstrate the benefits of visual cues to enhance speech understanding even when visual acuity is not optimal.SumarioLa comprensión del lenguaje mejora cuando el observador puede tanto ver como oír a su interlocutor. Este estudio compara los efectos de una agudeza visual reducida, en el reconocimiento auditivo-visual (AV) del lenguaje con ruido, entre adultos jóvenes y mayores. Dos grupos de participantes realizaron una tarea de reconocimiento de oraciones en contexto cerrado en una condición solo auditiva (Solo-A) y en tres condiciones AV: con agudeza visual normal (6/6) y con visión borrosa simulando impedimentos visuales de 6/30 y 6/60. Los resultados mostraron: (1) la adición de claves visuales de lenguaje mejora la percepción del mismo en relación con la condición de Solo-A; (2) en las condiciones AV, el desempeño declinó conforme aumentó el grado de visión borrosa; (3) incluso en la condición AV que simulaba una agudeza visual de 6/60, las puntuaciones en el reconocimiento del lenguaje fueron significativamente superiores que las obtenidas en la condición de Solo-A y (4) generalmente, los adultos jóvenes obtuvieron puntuaciones más altas que los adultos mayores, en todas las condiciones. Nuestros resultados demuestran los beneficios de las claves visuales para aumentar la comprensión del lenguaje, incluso cuando la agudeza visual no es óptima.

This study was designed to examine how speaking rate affects auditory-only, visual-only, and auditory-visual speech perception across the adult lifespan. In addition, the study examined the extent to which unimodal (auditory-only and visual-only) performance predicts auditory-visual performance across a range of speaking rates. The authors hypothesized significant Age × Rate interactions in all three modalities and that unimodal performance would account for a majority of the variance in auditory-visual speech perception for speaking rates that are both slower and faster than normal. Participants (N = 145), ranging in age from 22 to 92, were tested in conditions with auditory-only, visual-only, and auditory-visual presentations using a closed-set speech perception test. Five different speaking rates were presented in each modality: an unmodified (normal rate), two rates that were slower than normal, and two rates that were faster than normal. Signal to noise ratios were set individually to produce approximately 30% correct identification in the auditory-only condition and this signal to noise ratio was used in the auditory-only and auditory-visual conditions. Age × Rate interactions were observed for the fastest speaking rates in both the visual-only and auditory-visual conditions. Unimodal performance accounted for at least 60% of the variance in auditory-visual performance for all five speaking rates. The findings demonstrate that the disproportionate difficulty that older adults have with rapid speech for auditory-only presentations can also be observed with visual-only and auditory-visual presentations. Taken together, the present analyses of age and individual differences indicate a generalized age-related decline in the ability to understand speech produced at fast speaking rates. The finding that auditory-visual speech performance was almost entirely predicted by unimodal performance across all five speaking rates has important clinical implications for auditory-visual speech perception and the ability of older adults to use visual speech information to compensate for age-related hearing loss.

Effective processing of multisensory stimuli relies on both the peripheral sensory organs and central processing in subcortical and cortical structures. As we age, there are significant changes in all sensory systems and a variety of cognitive functions. Visual acuity tends to decrease and hearing thresholds generally increase (Kalina 1997; Liu and Yan 2007), whereas performance levels on tasks of motor speed, executive function, and memory typically decline (Rapp and Heindel 1994; Birren and Fisher 1995; Rhodes 2004). There are also widespread changes in the aging brain, including reductions in gray and white matter volume (Good et al. 2001; Salat et al. 2009), alterations in neurotransmitter systems (Muir 1997; Backman et al. 2006), regional hypoperfusion (Martin et al. 1991; Bertsch et al. 2009), and altered patterns of functional activity during cognitive tasks (Cabeza et al. 2004; Grady 2008). Given the extent of age-related alterations in sensation, perception, and cognition, as well as in the anatomy and physiology of the brain, it is not surprising that multisensory integration also changes with age.Several early studies provided mixed results on the differences between multisensory processing in older and younger adults (Stine et al. 1990; Helfer 1998; Strupp et al. 1999; Cienkowski and Carney 2002; Sommers et al. 2005). For example, Stine and colleagues (1990) reported that although younger adults’ memory for news events was better after audiovisual presentation than after auditory information alone, older adults did not show improvement during the multisensory conditions. In contrast, Cienkowski and Carney (2002) demonstrated that audiovisual integration on the McGurk illusion was similar for older and younger adults, and that in some conditions, older adults were even more likely to report the fusion of visual and auditory information than their young counterparts. Similarly, in a study examining the contribution of somatosensory input to participants’ perception of visuospatial orientation, Strupp et al. (1999) reported an age-related increase in the integration of somatosensory information into the multisensory representation of body orientation.Despite providing a good indication that multisensory processing is somehow altered in aging, the results of these studies are somewhat difficult to interpret due to their use of complex cognitive tasks and illusions, and to the variability in analysis methods. Several newer studies that have attempted to address these factors more clearly demonstrate that multisensory integration is enhanced in older adults (Laurienti et al. 2006; Peiffer et al. 2007; Diederich et al. 2008).On a two-choice audiovisual discrimination task, Laurienti and colleagues (2006) showed that response time (RT) benefits for multisensory versus unisensory targets were larger for older adults than for younger adults (Figure 20.1). That is, older adults’ responses during audiovisual conditions were speeded more than younger adults’, when compared with their respective responses during unisensory conditions. Multisensory gains in older adults remained significantly larger than those observed in younger adults, even after controlling for the presence of two targets in the multisensory condition (redundant target effect; Miller 1982, 1986; Laurienti et al. 2006).Using similar analysis methods, Peiffer et al. (2007) also reported increased multisensory gains in older adults. On a simple RT task, where average unisensory RTs were equivalent in younger and older adults, older adults actually responded faster than younger adults on multisensory trials because of their enhanced multisensory integration (Peiffer et al. 2007). Diederich and colleagues (2008) have also shown that older adults exhibit greater speeding of responses to multisensory targets than younger adults on a saccadic RT task. The analysis methods used in this experiment indicate a slowing of peripheral sensory processing, as well as a wider time window over which integration of auditory and visual stimuli can occur (Diederich et al. 2008).These experiments highlight several possible explanations that could help answer a critical question about multisensory processing in aging: Why do older adults exhibit greater integration of multisensory stimuli than younger adults? Potential sources of enhanced integration in older adults include age-related cognitive slowing not specific to multisensory processing, inverse effectiveness associated with sensory deficits, alterations in the temporal parameters of integration, and inefficient top–down modulation of sensory processing. In the following sections we will investigate each of these possible explanations in greater detail and offer some alternative hypotheses for the basis of enhanced multisensory integration in older adults.

The purpose of the current study was to examine how age-related hearing impairment affects lipreading and auditory-visual integration. The working hypothesis for the investigation was that presbycusic hearing loss would increase reliance on visual speech information, resulting in better lipreading and auditory-visual integration in older persons who have hearing impairment, compared with older persons who have normal hearing. This study compared the performance of 53 adults with normal hearing (above age 65) and 24 adults with mild-to-moderate hearing impairment (above age 65) on auditory-only (A), visual-only (V), and auditory-visual (AV) speech perception, using consonants, words, and sentences as stimuli. All testing was conducted in the presence of multi-talker background babble, set individually for each participant and each type of stimulus, to obtain approximately equivalent A performance across the groups. In addition, we compared the two groups of participants on measures of auditory enhancement, visual enhancement, and auditory-visual integration that were derived from the A, V and AV performance scores. In general, the two groups of participants performed similarly on measures of V and AV speech perception. The one exception to this finding was that the participants with hearing impairment performed significantly better than the participants with normal hearing on V identification of words. Measures of visual enhancement, auditory enhancement, and auditory-visual integration did not differ as a function of hearing status. Overall, the results of the current study suggest that despite increased reliance on visual speech information, older adults who have hearing impairment do not exhibit better V speech perception or auditory-visual integration than age-matched individuals who have normal hearing. These findings indicate that inclusion of V and AV speech perception measures can provide important information for designing maximally effective audiological rehabilitation strategies.

ABSTRACTMeaningful intergenerational interactions between older and younger adults are rare outside of family relationships. Interventions to increase positive intergenerational interactions are growing, but finding appropriate measures of attitudes toward both younger and older age groups is difficult. Many measures assessing attitudes toward older adults can remind participants of negative stereotypes of aging and are rarely used to assess attitudes toward younger adults. We adapted Pittinsky, Rosenthal, and Montoya’s allophilia measure to assess attitudes toward younger (18–25 years old) and older (over age 65) adults. In the first study, 94 traditional college age and 52 older adults rated older and younger adults. The allophilia measure distinguished between younger and older adults’ attitudes toward each age group. In the second study, we compared the age-related allophilia measures with seven traditional measures of attitudes toward older adults. Forty-seven traditional college age students completed measures. As predicted, correlations between allophilia toward older adults and the traditional semantic differential measures were weak (i.e., r = |0.15|or less), whereas correlations with general attitudes toward older adults were more moderate (r = 0.59 or less). Correlations between allophilia toward younger adults and the traditional measures were primarily non-significant as predicted. The allophilia measure differentiated between the five domains of positive attitudes toward younger and older adults and was not highly correlated with measures of more negative attitudes toward older adults. Results suggest that the allophilia measure can fill a need for a measure of positive attitudes toward older and younger adults.

The interaction of the triceps surae muscles and the Achilles tendon is critical in producing the ankle plantarflexion torque required for human walking. Deficits in plantarflexor output are a hallmark of reduced mobility in older adults and are likely associated with changes in the triceps surae muscles that occur with age. Structural differences between young and older adults have been observed in the Achilles tendon and in the triceps surae muscles. However, less is known about how age-related differences in muscle and tendon morphology correspond with each other and, furthermore, how those morphology differences correlate with age-related deficits in function. The goal of this work was to investigate whether there is a correlation between age-related differences in triceps surae muscle size and Achilles tendon cross-sectional area (CSA) and whether either is predictive of ankle plantarflexion torque during walking. We used magnetic resonance imaging (MRI) to measure triceps surae muscle volumes and tendon CSAs in young (n = 14, age: 26 ± 4 years) and older (n = 7, age: 66 ± 5 years) adults, and we determined peak plantarflexion torques during treadmill walking. We found that individual muscle volumes as a percentage of the total triceps surae volume did not differ between young and older adults, though muscle volumes per body size (normalized by the product of height and mass) were smaller in older adults. Achilles tendon CSA was correlated with body size and muscle volumes in young adults but not in older adults. The ratio of tendon CSA to total triceps surae muscle volume was significantly greater in older adults. Peak ankle plantarflexion torque during walking correlated with body size and triceps surae volume in young and older adults but was correlated with tendon CSA only in the young adults. Structure–function relationships that seem to exist between the Achilles tendon and the triceps surae muscles in young adults are no longer evident in all older adults. Understanding mechanisms that determine altered Achilles tendon CSA in older adults may provide insight into age-related changes in function.

Functional Assessment in Younger and Older Adults with Sickle Cell Disease

High Diagnostic Uncertainty and Inaccuracy in Adult Emergency Department Patients With Dyspnea: A National Database Analysis.

Visual enhancement in speech perception refers to the benefit obtained from seeing and hearing a talker, compared with listening alone. Previous studies comparing visual enhancement in younger (under age 25) and older (over age 65) adults have been confounded by age-related hearing loss. Therefore, the present study was designed to compare visual enhancement for consonants, words, and sentences in normal-hearing older and younger adults. All participants had clinically normal audiograms for octave frequencies from 250 Hz to 4 kHz. Consonant identification was tested using the Iowa Consonant Confusion Test. Word identification was measured using the Children’s Auditory–Visual Enhancement Test and sentence identification was measured using the Iowa Sentence Test. All testing was conducted in the presence of a multitalker background babble and baseline differences in auditory-only performance were minimized by setting signal-to-babble ratios individually to produce approximately 50% correct identification inthe auditory-only conditions. Visual enhancement, computed as the relative benefit obtained from adding visual speech information to the auditory signal, was significantly higher for younger than for older adults for consonants and words, but not for sentences. The results are discussed as supporting an age-related decline in intermodal sensory integration.

The hyperemic response to passive leg movement (PLM) is largely (~80%) nitric oxide (NO) mediated in young adults, whereas both the overall response and NO contribution (~20%) are diminished in older adults. A transient hyperemic response remains in both groups after NO blockade, however, the mechanisms contributing to this remaining response are unknown. Vasodilatory substances including prostaglandins (PG) and endothelial derived hyperpolarizing factors (EDHF) are primary candidates contributing to PLM response. Moreover, these underlying mechanisms of the PLM response are likely influenced by exercise training in both young and older adults but this remains to be determined. Thus, we sought to determine if 1) PG and EDHF contribute to the hyperemic response in older adults, and 2) exercise training alters the mechanisms contributing to changes in PLM (i.e., NO, PG, or EDHF). The leg blood flow (LBF) response to PLM was measured by Doppler ultrasound in 9 young (25±4 yr) and 9 older (69±5 yr) adult males. PLM was performed with intra-arterial infusions of saline (control), NG-monomethyl-L-arginine (L-NMMA) to inhibit NOS and NO production, and a combination of L-NMMA, ketorolac tromethamine (KET) to inhibit cyclooxygenase and PG production, and fluconazole (FLUC) to inhibit cytochrome P-450 and EDHF (L-NMMA+KET+FLUC). This PLM and drug infusion protocol were repeated following 8 weeks of single leg knee-extension (KE) exercise training to determine if the vasodilatory mechanisms regulating PLM-induced hyperemia are altered by exercise training. The hyperemic response to PLM (total LBF area under the curve) was significantly attenuated from control with infusion of L-NMMA in young adults (-287±280 mL, p<0.05) but remained unchanged in the older (-55±86 mL, P=0.70). Combined infusion of L-NMMA+KET+FLUC yielded similar results such that PLM decreased to the same degree as L-NMMA in young (-276±108 mL, p<0.05) with no significant change in older adults (-116±81 mL, P=0.36). Following 8 weeks of single leg KE training, maximal power (KEmax) improved in both young (+33±13 W, p<0.05) and older adults (+16±8 W, p<0.05). Despite improvements in KEmax, the hyperemic response to PLM only increased in young adults by ~30% (454±194 v. 604±351 mL, p<0.05), while no improvement was observed in older adults (225±142 v. 236±89 mL, P=0.86). The contribution of NO to PLM did not change following exercise training in either young (-238±217 mL, P=0.14) or older (-62±82 mL, P=0.72) adults. Likewise, the contribution of PG and EDHF also did not change in both young (-306±222 mL, P=0.68) and older (-108±116 mL, P=0.77) adults. These findings indicate that PG and EDHF do not have an additive effect to NO on the hyperemic response to PLM in both young and older adults. Therefore, the remaining hyperemic response following combined NO, PG, and EDHF inhibition is likely driven by non-endothelial dependent mechanisms. Moreover, these data indicate that 8 weeks of KE specific exercise training significantly improves the hyperemic response to PLM in young but not older adults. Interestingly, the observed improvements to PLM were not directly mediated through the NO, PG, or EDHF pathways but by some other, currently unidentified, mechanism. National Institutes of Health R01HL142603 (to J.D. Trinity) This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

The purpose of this experiment was to quantify the contribution of visual text to auditory speech recognition in background noise. Specifically, the authors tested the hypothesis that partially accurate visual text from an automatic speech recognizer could be used successfully to supplement speech understanding in difficult listening conditions in older adults, with normal or impaired hearing. The working hypotheses were based on what is known regarding audiovisual speech perception in the elderly from speechreading literature. We hypothesized that (1) combining auditory and visual text information will result in improved recognition accuracy compared with auditory or visual text information alone, (2) benefit from supplementing speech with visual text (auditory and visual enhancement) in young adults will be greater than that in older adults, and (3) individual differences in performance on perceptual measures would be associated with cognitive abilities. Fifteen young adults with normal hearing, 15 older adults with normal hearing, and 15 older adults with hearing loss participated in this study. All participants completed sentence recognition tasks in auditory-only, text-only, and combined auditory-text conditions. The auditory sentence stimuli were spectrally shaped to restore audibility for the older participants with impaired hearing. All participants also completed various cognitive measures, including measures of working memory, processing speed, verbal comprehension, perceptual and cognitive speed, processing efficiency, inhibition, and the ability to form wholes from parts. Group effects were examined for each of the perceptual and cognitive measures. Audiovisual benefit was calculated relative to performance on auditory- and visual-text only conditions. Finally, the relationship between perceptual measures and other independent measures were examined using principal-component factor analyses, followed by regression analyses. Both young and older adults performed similarly on 9 out of 10 perceptual measures (auditory, visual, and combined measures). Combining degraded speech with partially correct text from an automatic speech recognizer improved the understanding of speech in both young and older adults, relative to both auditory- and text-only performance. In all subjects, cognition emerged as a key predictor for a general speech-text integration ability. These results suggest that neither age nor hearing loss affected the ability of subjects to benefit from text when used to support speech, after ensuring audibility through spectral shaping. These results also suggest that the benefit obtained by supplementing auditory input with partially accurate text is modulated by cognitive ability, specifically lexical and verbal skills.

BackgroundCardiovascular diseases (CVDs) are a major cause of morbidity and mortality worldwide, with data showing an increasing trend. Previously uncommon, CVDs of lifestyle are now increasing in many Sub-Sahara African (SSA) countries including Tanzania. The study aimed at determining the spectrum and distribution of CVDs among young (< 45 years) and older (≥ 45 years) adults referred for echocardiography at Jakaya Kikwete Cardiac Institute (JKCI).MethodsHospital-based cross sectional study was conducted among adult patients referred for echocardiography at JKCI between July and December 2021. Patient’s socio-demographic and clinical characteristics were recorded. CVD diagnoses were made using established diagnostic criterias. Comparisons were done using chi-square test and student’s t-test. Multivariable logistic regression analysis was used to determine factors associated with abnormal echocardiography. A significance level was set at p-value < 0.05.ResultsIn total 1,050 patients (750 old and 300 young adults) were enrolled. The mean ± SD age was 62.2 ± 10.4 years and 33.5 ± 7.4 years for older and young adults respectively. Hypertension was the commonest indication for echocardiography both in the young (31%) and older (80%) adults. Majority of older adults were found to have abnormal echocardiography (90.7%), while only 44.7% of the young adults had abnormal echocardiography (p < 0.001). For the older adults, the commonest diagnoses were HHD (70.3%), IHD (9.7%), and non-ischemic cardiomyopathy (6.1%) while for young adults, HHD (16.7%), non-ischemic cardiomyopathy (8%), RHD (8%) and MVP (4.3%) were the commonest. The differences in the echocardiographic diagnoses between young and older adults were statistically significant, p < 0.001. Being an older adult, hypertensive, overweight/obese were independently associated with abnormal echocardiography (p < 0.01).ConclusionHypertensive heart disease is the most common diagnosis among adult patients referred for echocardiography at JKCI, both in young and older adults. Primary prevention, early detection and treatment of systemic hypertension should be reinforced in order to delay or prevent its complications.

Objective:Epilepsy is the third most common neurological disorder among older adults, and as adults are living longer, the incidence of epilepsy is increasing (Kun Lee, 2019). The purpose of this study is to examine 1. differences in quality of life (QOL) between older and younger adults with medically intractable epilepsy and 2. the impact of seizure frequency, seizure duration, depression, sex, and marital status on QOL. Given differences in the prevalence rates of depression between men and women and importance of depression in QOL, we predicted that sex and marital status would moderate the effect of depression on total QOL (TQOL).Hypothesis I: Compared to younger adults, older adults with epilepsy will report lower TQOL scores and lower scores on subscales measuring energy/fatigue, cognition, and medication effects. Hypothesis II: Seizure variables and depression will significantly account for TQOL scores in both groups (younger and older) above demographic variables (sex, marital status, and education). Hypothesis III: Sex will moderate the effect of depression in both groups and marital status will moderate the effect of depression only in the older adults.Participants and Methods:Participants were 607 adults (&gt; 18 years old) who were prospective candidates for epilepsy surgery and underwent a comprehensive neuropsychological evaluation including QOL assessment using the Quality of Life in Epilepsy Scale-31 (QOLIE-31). Individuals were grouped by older (&gt; 50 years old; N = 122) and younger adults (&lt; 50 years old; N = 485). Hierarchical regression was used to examine the proposed associations.Results:Hypothesis I: In contrast to our hypothesis, a one-way ANOVA did not reveal significant differences between the older and younger groups on the QOL subscales, TQOL, or depression.Hypothesis II: For older adults, longer seizure duration was associated with better TQOL; bivariate correlations showed no evidence of statistical suppression. Higher depression scores were associated with worse TQOL. Overall, the model accounted for 39.6% of variance among older adults. For younger adults, only depression was a significant predictor of TQOL wherein higher depression scores were associated with worse TQOL. Overall, the model accounted for 36.1% of the variance among younger adults. Hypothesis III: There was no moderation between depression and marital status in older or younger adults (b = -.009, p &gt; .05). There was multicollinearity evidenced by VIF (variance inflation factor) greater than 10, so the associations between depression and sex could not be examined.Conclusions:Overall, there were no significant differences between QOL in younger versus older adults. Greater depression symptoms were associated with lower TQOL in both groups. Longer seizure duration was a significant predictor of better TQOL in older adults only, perhaps indicating better adjustment to having a seizure disorder with longer duration of epilepsy. Lastly, marital status did not moderate the effects of depression on TQOL and the moderating effects of sex on TQOL could not be assessed due to multicollinearity. Study limitations include dichotomizing the sample into these particular age groups and the heterogeneity of seizure types.