Footedness is a better predictor than is handedness of emotional lateralization.

A tremendous amount of experimental work has attempted to identify reliable behavioural predictors of cerebral lateralization. Preferred handedness has been the most popular predictor, but some recent reports suggest that preferred footedness may serve as a more accurate predictor of functional laterality, especially in the left-handed population. The present study sought to test this claim by selectively recruiting individuals with either 'crossed' lateral preferences (right-handed and left-footed or left-handed and right-footed) or 'uncrossed' lateral preferences (right-handed and right-footed or left-handed and left-footed). Lateralization of emotional perception was assessed with two blocks of the dichotic Emotional Words Test (EWT), and lateral preference for both handedness and footedness was assessed using self-report questionnaires. Ear advantage on the dichotic task varied significantly with preferred foot (P=0.003), but not with preferred hand. Cerebral lateralization may be more related to footedness than to other lateral preferences.

Visual temporal asymmetries are related to asymmetries in linguistic perception.

There are numerous recent reports of low-level temporal asymmetries favouring the left hemisphere, and increasing speculation that the left hemisphere's relative superiority at linguistic processing may be related to these asymmetries. The present study sought to test this claim by assessing linguistic lateralization with the Fused Dichotic Words Test and visual temporal asymmetries with a lateralized version of an inspection-time test in a sample of 40 participants balanced for sex and handedness. We found evidence for a significant right-visual-field (left-hemisphere) advantage for accuracy on the inspection-time task, F(1,36)=4.38, P = 0.043, and this asymmetry was significantly correlated with laterality scores on the linguistic dichotic-listening task, r = 0.306, P < 0.028 before disattenuation, and r = 0.486 after disattenuation. This result supports the position that low-level temporal asymmetries are related to asymmetries in linguistic processing.

Differing perspectives on outcome after subarachnoid hemorrhage: the patient, the relative, the neurosurgeon.

OBJECTIVE: To better understand patients' and relatives' views of outcome after surgery for subarachnoid hemorrhage (SAH), we evaluated neurobehavioral changes, psychological distress, and family burden of patients who had been considered by their neurosurgeon as having a "good recovery" or a "moderate disability," as rated on the Glasgow Outcome Scale. METHODS: A heterogeneous sample of 28 patients treated surgically for SAH from an aneurysm or an arteriovenous malformation and their relatives separately underwent a semistructured interview. They also completed a revised version of the Adjective Checklist to assess their perceptions of the patient's neurobehavioral changes and the Brief Symptom Inventory as a measure of their own psychological distress. Levels of family burden on the relatives were evaluated with a Likert strain scale and the Zarit Burden Interview. RESULTS: Approximately 19 months after surgery for SAH, the majority of the patients reported significant negative neurobehavioral changes and negative changes in employment, energy levels, tolerance to mild stressors, leisure activities, and social and sexual relationships. Patients and relatives both reported elevated levels of psychological distress, and the relatives reported elevated levels of family burden. Patients' and relatives' perceptions differed, with the relatives reporting more problems; both viewed the patient's outcome more negatively than did the operating neurosurgeon. CONCLUSION: Despite the neurosurgeon's classification of patients as having a "good recovery" or "moderate disability," the majority of patients surgically treated for SAH reported psychosocial and neurobehavioral changes that were disabling for them and burdensome to their family. Patients and relatives who are interviewed separately by an experienced clinician may provide differing perspectives on SAH outcome that are not necessarily good.

Personality & behaviour changes following spinal cord injury: self perceptions--partner's perceptions.

There has been little specific investigation of personality and behaviour changes following spinal cord injury (SCI) and only limited consideration of the possible impact of concurrent traumatic brain injury (TBI). By mail-out questionnaire, we evaluated personality and behaviour changes in a married group (n = 9) with traumatic SCI, who knew their partners prior to injury, and who had not been identified as having concurrent TBI on referral to the Canadian Paraplegic Association. Both the person with SCI (and the partner) completed the revised Adjective Checklist and by their combined report, there were significant personality and behaviour changes. Unexpectedly, five individuals described post-traumatic amnesia (PTA) > or = 3 days. Subsequently, participants' reports were further divided into two groups--"longer PTA" and "shorter PTA". The "longer PTA" group self-reported less change and more positive change than did their partners. The "longer PTA" partners described changes that are consistent with the profile of TBI. The "shorter PTA" group described themselves more negatively than did their partners. Given the size of the groups (n = 5, n = 4), these findings are presented to illustrate trends and to stimulate further research.

Psychological distress and family burden following spinal cord injury: concurrent traumatic brain injury cannot be overlooked.

Although concurrent spinal cord injury (SCI) and traumatic brain injury (TBI) are recognized, there is little acknowledgement of SCI/TBI as a contributor to psychological distress and family burden. By mail-out questionnaire, we evaluated psychological distress and family burden in a married group (n = 12) with traumatic SCI who had not been identified as having concurrent TBI on referral to the Canadian Paraplegic Association. Both the person with SCI and the partner completed the Brief Symptom Inventory (BSI), the Adjective Checklist, and a Likert strain scale to measure the perception of the partner's strain. The partner also completed the Zarit Burden Interview. Despite screening criteria designed to selectively recruit individuals without TBI, seven individuals described post-traumatic amnesia (PTA) > or = 3 days. Subsequently, participants' reports were divided into two groups--"longer PTA" and "shorter PTA". On the Brief Symptom Inventory, the two SCI groups did not differ, but the partners of individuals with "longer PTA" had significantly elevated Global Severity Index scores compared to the other partners. The "longer PTA" partner group demonstrated more strain and more burden (as measured by the Likert strain scale and the Zarit Burden Interview). Given the size of the groups (n = 7, n = 5), these findings are presented to illustrate trends and to stimulate further research.

Footedness is a better predictor of language lateralisation than handedness.

A tremendous amount of experimental work has attempted to identify a reliable behavioural predictor of language lateralisation. Preferred handedness has probably received the most attention, but there are some recent reports that preferred footedness may serve as a more reliable predictor. The present study sought to test this claim by selectively recruiting 32 participants such that the factors of handedness, footedness, and gender were completely crossed. Language lateralisation was assessed with the Fused Dichotic Words Test (FDWT), and lateral preference for both handedness and footedness was assessed using self-report questionnaires. Ear advantage on the dichotic task varied significantly with preferred foot ( P <.001) but not with preferred hand ( P = .196). This result is problematic for evolutionary theories of cerebral lateralisation that claim left-hemispheric language is related to fine manual motor skill and sequencing. Language lateralisation may be more closely related to asymmetrical control of whole-body finely sequenced movements.

Lateral and sex differences in manual gesture during conversation.

To examine whether sex differences in cerebral lateralisation for speech can be observed through lateral differences in manual gesturing during natural conversation, 100 individuals (50 male and 50 female) were observed following a procedure similar to that described by Kimura (1973a,b). For males, there was a significant increase in the number of gestures made with the right hand during speech. When males were listening, there was a significant increase in the number of gestures made with the left hand. This result was not observed in the females studied, who did not demonstrate significant manual asymmetries in gesturing during either speech or listening. This result is consistent with claims that there is a sex difference in hemispheric specialisation wherein males are more functionally lateralised than females.

Handedness and depression in university students: a sex by handedness interaction.

Previous research has indicated that there is an increased incidence of left-handedness in samples of depressed individuals. We administered the Beck Depression Inventory (BDI) to a sample of 541 undergraduate students. Left-handed males showed significant elevation of BDI scores. It is unlikely that this result is due to decreased right hemisphere activity or sex-role conflicts. However, one possibility is that known differences in male steroid hormones levels between right- and left-handers contributed to this effect. Press

Linguistic lateralization and asymmetries in interhemispheric transmission time.

The Interhemispheric Conduction Delay (ICD) theory of cerebral lateralization claims that longer interhemispheric transfer times (IHTT's) should result in greater functional lateralization for time-critical tasks. IHTT was estimated in 40 normal participants using both a visual and an auditory version of the Poffenberger (1912) paradigm. There was a significant response-hand by side-of-presentation interaction, and the length of IHTT for auditory information being transferred from the right to left hemisphere was significantly related to linguistic lateralization as assessed with a dichotic-listening task. These results support the ICD theory of cerebral lateralization.

Tactile gap detection and language lateralization.

Recent work suggests that hemispheric language lateralization might be related to the fine-grained temporal discriminations that are required for linguistic processing (Nicholls, 1996). Studies concerning tactile processing have also shown a significant left-hemisphere (L-H) advantage for tactile gap detection (Nicholls & Whelan, 1997). We hypothesized that language and tactile processing are both preferentially processed by the left hemisphere because it is specialized for tasks requiring fine-grained temporal resolution. Thirty-two participants (16 right and 16 left handers) were tested for both linguistic processing (using the Fused Dichotic Words Test (FDWT)) and tactile gap detection. Both right and left handers showed a significant L-H advantage for both language processing and tactile gap detection. The present study supports recent claims that language lateralization is attributable to the left hemisphere's better suitability to process tasks that require fine-grained temporal resolution.